How is infrared light used in therapy?
Infrared sauna
"Infrared therapy" uses infrared heaters to emit infrared light experienced as radiant heat which is absorbed by the surface of the skin. Saunas heat the body primarily by conduction and convection from the heated air and by radiation of the heated surfaces in the sauna room. Because of this, infrared therapy is not considered a sauna by Finnish sauna societies. Nevertheless, "Infrared Sauna" and "Infrared Therapy" are respectively a methodology and a terminology in the application of the infrared electromagnetic field spectrum to the human body. There are claims of detoxification which lack scientific evidence. There are at least 48 scientific or medical articles on "Infrared Sauna", 327 on "Far Infrared Therapy" and over twenty one thousand on "Infrared Therapy" some of which investigate health benefits, such as prophylactic physiotherapeutic treatment schemes, appetite loss and depression, cardio vascular system improvements, and Photothermal Therapy.
Radio frequency
RF diathermy is a medical treatment that uses RF induced heat as a form of physical therapy and in surgical procedures. It is commonly used for muscle relaxation. It is also a method of heating tissue electromagnetically for therapeutic purposes in medicine. Diathermy is used in physical therapy to deliver moderate heat directly to pathologic lesions in the deeper tissues of the body. Surgically, the extreme heat that can be produced by diathermy may be used to destroy neoplasms, warts, and infected tissues, and to cauterize blood vessels to prevent excessive bleeding. The technique is particularly valuable in neurosurgery and surgery of the eye. Diathermy equipment typically operates in the short-wave radio frequency (range 1–100 MHz) or microwave energy (range 434–915 MHz).
Blacklight
Bili light. A type of phototheraphy that uses blue light with a range of 420–470 nm, used to treat neonatal jaundice.
Fluorescent lamp
Deep blue light generated from a europium-activated phosphor is used in the light therapy treatment of jaundice; light of this color penetrates skin and helps in the breakup of excess bilirubin.
Infrared photography
Many conventional cameras can be used for infrared photography, where infrared is taken to mean light of a wavelength only slightly longer than that of visible light. Photography of rather longer wavelengths is normally termed thermography and requires special equipment.
External beam radiotherapy
Intensity modulated radiation therapy (IMRT) is an advanced radiotherapy technique used to minimize the amount of normal tissue being irradiated in the treatment field. In some systems this intensity modulation is achieved by moving the leaves in the MLC during the course of treatment, thereby delivering a radiation field with a non-uniform (i.e. modulated) intensity. With IMRT, radiation oncologists are able to break up the radiation beam into many "beamlets". This allows radiation oncologists to vary the intensity of each beamlet. With IMRT, doctors are often able to further limit the amount of radiation received by healthy tissue near the tumor. Doctors have found this sometimes allowed them to safely give a higher dose of radiation to the tumor, potentially increasing the chance of a cure.
Bili light
A bili light is a light therapy tool to treat newborn jaundice (hyperbilirubinemia). High levels of bilirubin can cause brain damage (kernicterus), leading to cerebral palsy, auditory neuropathy, gaze abnormalities and dental enamel hypoplasia. The therapy uses a blue light (420–470 nm) that converts bilirubin into a form that can be excreted in the urine and feces. Soft eye shields are placed on the babies to protect their eyes from damage that may lead to retinopathy due to the bili lights.
Infrared
Infrared light is also useful for observing the cores of active galaxies, which are often cloaked in gas and dust. Distant galaxies with a high redshift will have the peak portion of their spectrum shifted toward longer wavelengths, so they are more readily observed in the infrared.
Infrared lamp
Infrared lamps are electrical devices which emit infrared radiation. Infrared lamps are commonly used in radiant heating for industrial processes and building heating. Infrared LEDs are used for communication over optical fibers and in remote control devices. Infrared lamps are also used for some night vision devices where visible light would be objectionable. Infrared lamp sources are used in certain scientific and industrial instrument for chemical analysis of liquids and gases; for example, the pollutant sulfur dioxide in air can be measured using its infrared absorption characteristics.
Ultraviolet light therapy
Phototherapy is used for many dermatologic conditions. However, the time and expense can be a burden and obstacle for many patients. For patients with psoriasis, the use of tanning beds can be beneficial. (Psoriasis is a skin condition with symptoms of red flaky skin). Commercial tanning facilities offer an alternative means of phototherapy outside of a doctor's office. Tanning beds at commercial facilities are already being used by people with psoriasis; a survey showed that 36% of patients have tried commercial tanning beds to treat their psoriasis. Tanning beds are, in fact, the most common form of phototherapy.
Telecommand
Infrared light makes up the invisible section of the electromagnetic spectrum. This light, also classified as heat, transmits signals between the transmitter and receiver of the remote system. Telecommand systems usually include a physical remote, which contains four key parts: buttons, integrated circuit, button contacts, and a light-emitting diode. When the buttons on a remote are pressed they touch and close their corresponding contacts below them within the remote. This completes the necessary circuit on the circuit board along with a change in electrical resistance, which is detected by the integrated circuit. Based on the change in electrical resistance, the integrated circuit distinguishes which button was pushed and sends a corresponding binary code to the light-emitting diode (LED) usually located at the front of the remote. To transfer the information from the remote to the receiver, the LED turns the electrical signals into an invisible beam of infrared light that corresponds with the binary code and sends this light to the receiver. The receiver then detects the light signal via a photodiode and it is transformed into an electrical signal for the command and is sent to the receiver’s integrated circuit/microprocessor to process and complete the command. The strength of the transmitting LED can vary and determines the required positioning accuracy of the remote in relevance to the receiver. Infrared remotes have a maximum range of approximately 30 feet and require the remote control or transmitter and receiver to be within a line of sight.
Breathalyzer
Infrared-based breath analyzers project an infrared beam of radiation through the captured breath in the sample chamber and detect the absorbance of the compound as a function of the wavelength of the beam, producing an absorbance spectrum that can be used to identify the compound, as the absorbance is due to the harmonic vibration and stretching of specific bonds in the molecule at specific wavelengths (see infrared spectroscopy). The characteristic bond of alcohols in infrared is the O-H bond, which gives a strong absorbance at a short wavelength. The more light is absorbed by compounds containing the alcohol group, the less reaches the detector on the other side—and the higher the reading. Other groups, most notably aromatic rings and carboxylic acids can give similar absorbance readings.
Heat therapy
Infrared (IR for short) is the part of the electromagnetic radiation spectrum comprised between 0.78 μm and 1 mm wavelength. It is usually divided into three segments:
Vitiligo
Phototherapy is considered a second-line treatment for vitiligo. Exposing the skin to light from UVB lamps is the most common treatment for vitiligo. The treatments can be done at home with an UVB lamp or in a clinic. The exposure time is managed so that the skin does not suffer overexposure. Treatment can take a few weeks if the spots are on the neck and face and if they existed not more than 3 years. If the spots are on the hands and legs and have been there more than 3 years, it can take a few months. Phototherapy sessions are done 2–3 times a week. Spots on a large area of the body may require full body treatment in a clinic or hospital. UVB broadband and narrowband lamps can be used, but narrowband ultraviolet picked around 311 nm is the choice. It has been constitutively reported that a combination of UVB phototherapy with other topical treatments improves re-pigmentation. However, some vitiligo patients may not see any changes to skin or re-pigmentation occurring. A serious potential side effect involves the risk of developing skin cancer, the same risk as an over-exposure to natural sunlight.
Infrared
Infrared radiation (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with longer wavelengths than those of visible light, and is therefore generally invisible to the human eye, although IR at wavelengths up to 1050 nanometers (nm)s from specially pulsed lasers can be seen by humans under certain conditions. IR wavelengths extend from the nominal red edge of the visible spectrum at 700 nanometers (frequency 430 THz), to 1 millimeter (300 GHz). Most of the thermal radiation emitted by objects near room temperature is infrared. As with all EMR, IR carries radiant energy and behaves both like a wave and like its quantum particle, the photon.
Infrared cut-off filter
Infrared cut-off filters, sometimes called IR filters or heat-absorbing filters, are designed to reflect or block mid-infrared wavelengths while passing visible light. They are often used in devices with bright incandescent light bulbs (such as slide and overhead projectors) to prevent unwanted heating. There are also filters which are used in solid state (CCD or CMOS) video cameras to block IR due to the high sensitivity of many camera sensors to near-infrared light. These filters typically have a blue hue to them as they also sometimes block some of the light from the longer red wavelengths.
Remote control
The main technology used in home remote controls is infrared (IR) light. The signal between a remote control handset and the device it controls consists of pulses of infrared light, which is invisible to the human eye but can be seen through a digital camera, video camera or a phone camera. The transmitter in the remote control handset sends out a stream of pulses of infrared light when the user presses a button on the handset. A transmitter is often a light emitting diode (LED) which is built into the pointing end of the remote control handset. The infrared light pulses form a pattern unique to that button. The receiver in the device recognizes the pattern and causes the device to respond accordingly.
Image-guided radiation therapy
Image-guided radiation therapy (IGRT) is the process of frequent two and three-dimensional imaging, during a course of radiation treatment, used to direct radiation therapy utilizing the imaging coordinates of the actual radiation treatment plan. The patient is localized in the treatment room in the same position as planned from the reference imaging dataset. An example of IGRT would include localization of a cone beam computed tomography (CBCT) dataset with the planning computed tomography (CT) dataset from planning. IGRT would also include matching planar kilovoltage (kV) radiographs or megavoltage (MV) images with digital reconstructed radiographs (DRRs) from the planning CT. These two methods comprise the bulk of IGRT strategies currently employed circa 2013.
Infrared
The infrared portion of the spectrum has several useful benefits for astronomers. Cold, dark molecular clouds of gas and dust in our galaxy will glow with radiated heat as they are irradiated by imbedded stars. Infrared can also be used to detect protostars before they begin to emit visible light. Stars emit a smaller portion of their energy in the infrared spectrum, so nearby cool objects such as planets can be more readily detected. (In the visible light spectrum, the glare from the star will drown out the reflected light from a planet.)
Intense pulsed light
The technology uses a high-powered, hand-held, computer-controlled flashgun to deliver an intense, visible, broad-spectrum pulse of light, generally in the visible spectral range of 400 to 1200 nm. Various cutoff filters are commonly used to selectively filter out shorter wavelengths, especially potentially damaging ultra violet light. The resulting light has a spectral range that targets specific structures and chromophores (e.g. melanin in hair, or oxyhemoglobin in blood vessels) that are heated to destruction and reabsorbed by the body. IPL shares some similarities with laser treatments, in that they both use light to heat and destroy their targets. But unlike lasers that use a single wavelength (color) of light which typically matches only one chromophore and hence only treats one condition, IPL uses a broad spectrum that when used with interchangeable filters, allows it to be used against several conditions. This can be achieved when the IPL technician selects the appropriate filter that matches a specific chromophore.
Forward-looking infrared
They can be used to help pilots and drivers steer their vehicles at night and in fog, or to detect warm objects against a cooler background. The wavelength of infrared that thermal imaging cameras detect is 3 to 12 μm and differs significantly from that of night vision, which operates in the visible light and near-infrared ranges (0.4 to 1.0  μm).
Infrared photography
Color infrared transparency films have three sensitized layers that, because of the way the dyes are coupled to these layers, reproduce infrared as red, red as green, and green as blue. All three layers are sensitive to blue so the film must be used with a yellow filter, since this will block blue light but allow the remaining colors to reach the film. The health of foliage can be determined from the relative strengths of green and infrared light reflected; this shows in color infrared as a shift from red (healthy) towards magenta (unhealthy). Early color infrared films were developed in the older E-4 process, but Kodak later manufactured a color transparency film that could be developed in standard E-6 chemistry, although more accurate results were obtained by developing using the AR-5 process. In general, color infrared does not need to be refocused to the infrared index mark on the lens.
Thermal infrared spectroscopy
Thermal infrared spectroscopy (TIR spectroscopy) is the subset of infrared spectroscopy that deals with radiation emitted in the infrared part of the electromagnetic spectrum. The emitted infrared radiation, though similar to blackbody radiation, is different in that the radiation is banded at characteristic vibrations in the material. The method measures the thermal infrared radiation emitted (as opposed to being transmitted or reflected) from a volume or surface. This method is commonly used to identify the composition of surface by analyzing its spectrum and comparing it to previously measured materials. It is particularly suited to airborne and spaceborne applications.
Infrared heater
Much of the infrared and visible energy released is caused by the direct heating of the quartz material, 97% of the near infrared is absorbed by the silica quartz glass tube causing the temperature of the tube wall to increase, this causes the silicon-oxygen bond to radiate far infrared rays. Quartz glass heating elements were originally designed for lighting applications, but when a lamp is at full power less than 5% of the emitted energy is in the visible spectrum.
Infrared photography
In infrared photography, the film or image sensor used is sensitive to infrared light. The part of the spectrum used is referred to as near-infrared to distinguish it from far-infrared, which is the domain of thermal imaging. Wavelengths used for photography range from about 700 nm to about 900 nm. Film is usually sensitive to visible light too, so an infrared-passing filter is used; this lets infrared (IR) light pass through to the camera, but blocks all or most of the visible light spectrum (the filter thus looks black or deep red). ("Infrared filter" may refer either to this type of filter or to one that blocks infrared but passes other wavelengths.)
Intraoperative radiation therapy
Intraoperative radiation therapy, or IORT, is the application of therapeutic levels of radiation to the tumor bed while the area is exposed during surgery. IORT is typically a component in the multidisciplinary treatment of locally advanced and recurrent cancer, in combination with external beam radiation, surgery and chemotherapy. As a growing trend in recent years, IORT can also be used in earlier stage cancers such as prostate and breast cancer.
Laser
Lasers are used to treat cancer by shrinking or destroying tumors or precancerous growths. They are most commonly used to treat superficial cancers that are on the surface of the body or the lining of internal organs. They are used to treat basal cell skin cancer and the very early stages of others like cervical, penile, vaginal, vulvar, and non-small cell lung cancer. Laser therapy is often combined with other treatments, such as surgery, chemotherapy, or radiation therapy. Laser-induced interstitial thermotherapy (LITT), or interstitial laser photocoagulation, uses lasers to treat some cancers using hyperthermia, which uses heat to shrink tumors by damaging or killing cancer cells. Lasers are more precise than traditional surgery methods and cause less damage, pain, bleeding, swelling, and scarring. A disadvantage is that surgeons must have specialized training. It may be more expensive than other treatments.
Near-infrared window in biological tissue
The near-infrared (NIR) window (also known as optical window or therapeutic window) defines the range of wavelengths from 650 to 1350 nanometre (nm) where light has its maximum depth of penetration in tissue. Within the NIR window, scattering is the most dominant light-tissue interaction, and therefore the propagating light becomes diffused rapidly. Since scattering increases the distance travelled by photons within tissue, the probability of photon absorption also increases. Because scattering has weak dependence on wavelength, the NIR window is primarily limited by the light absorption of blood at short wavelengths and water at long wavelengths. The technique using this window is called NIRS. Medical imaging techniques such as fluorescence image-guided surgery often make use of the NIR window to detect deep structures.
Infrared astronomy
Infrared and optical astronomy are often practiced using the same telescopes, as the same mirrors or lenses are usually effective over a wavelength range that includes both visible and infrared light. Both fields also use solid state detectors, though the specific type of solid state detectors used are different. Infrared light is absorbed at many wavelengths by water vapor in the Earth's atmosphere, so most infrared telescopes are at high elevations in dry places, above as much of the atmosphere as possible. There are also infrared observatories in space, including the Spitzer Space Telescope and the Herschel Space Observatory.
Blood irradiation therapy
Transcutaneous therapy applies laser light on unbroken skin in areas with large numbers of blood vessels (such as the forearm). Because of the skin acting as a barrier to the blood, absorbing low level laser energy, the power of the laser is often boosted to compensate.
The problem can be solved by using pulsed matrix laser light sources.
Infrared lamp
IR data transmission is also employed in short-range communication among computer peripherals and personal digital assistants. These devices usually conform to standards published by IrDA, the Infrared Data Association. Remote controls and IrDA devices use infrared light-emitting diodes (LEDs) to emit infrared radiation which is focused by a plastic lens into a narrow beam. The beam is modulated, i.e. switched on and off, to encode the data. The receiver uses a silicon photodiode to convert the infrared radiation to an electric current. It responds only to the rapidly pulsing signal created by the transmitter, and filters out slowly changing infrared radiation from ambient light. Infrared communications are useful for indoor use in areas of high population density. IR does not penetrate walls and so does not interfere with other devices in adjoining rooms. Infrared is the most common way for remote controls to command appliances.
Blood irradiation therapy
Blood irradiation therapy can be administered in three ways. Extracorporeally, drawing blood out and irradiating it in a special cuvette. This method is used for the ultraviolet (UV) blood irradiation (UVBI) by UV lamps. The laser light is monochromatic, i.e. it has such a wavelength that allows you to bring light into the optical fiber and carry out irradiation intravenously through a catheter in a vein. This method is more simple and effective. Blood irradiation therapy is also administered externally through the skin on the projection of large blood vessels.
Infrared lamp
Infrared heating uses infrared lamps, commonly called heat lamps to transmit infrared radiation to the body that is being heated. When bodies with a large surface area need to be heated, infrared lamps are often used in banks. Infrared heat lamps are commonly incandescent bulbs which are able to produce infrared radiation. Infrared lamps have many industrial applications including curing coatings and preparing plastic for forming, commercial applications such as cooking and browning food, and personal applications such as providing heat (especially in bathrooms and for pets).
Infrared spectroscopy
Infrared spectroscopy (IR spectroscopy or vibrational spectroscopy) involves the interaction of infrared radiation with matter. It covers a range of techniques, mostly based on absorption spectroscopy. As with all spectroscopic techniques, it can be used to identify and study chemicals. Samples may be solid, liquid, or gas. The method or technique of infrared spectroscopy is conducted with an instrument called an infrared spectrometer (or spectrophotometer) to produce an infrared spectrum. An IR spectrum can be visualized in a graph of infrared light absorbance (or transmittance) on the vertical axis vs. frequency or wavelength on the horizontal axis. Typical units of frequency used in IR spectra are reciprocal centimeters (sometimes called wave numbers), with the symbol cm. Units of IR wavelength are commonly given in micrometers (formerly called "microns"), symbol μm, which are related to wave numbers in a reciprocal way. A common laboratory instrument that uses this technique is a Fourier transform infrared (FTIR) spectrometer. Two-dimensional IR is also possible as discussed below.
Infrared spectroscopy
Fourier transform infrared (FTIR) spectroscopy is a measurement technique that allows one to record infrared spectra. Infrared light is guided through an interferometer and then through the sample (or vice versa). A moving mirror inside the apparatus alters the distribution of infrared light that passes through the interferometer. The signal directly recorded, called an "interferogram", represents light output as a function of mirror position. A data-processing technique called Fourier transform turns this raw data into the desired result (the sample's spectrum): Light output as a function of infrared wavelength (or equivalently, wavenumber). As described above, the sample's spectrum is always compared to a reference.
Ultraviolet light therapy
Side-effects may include itching and redness of the skin due to UVB exposure, and possibly sunburn, if patients do not minimize exposure to natural UV rays during treatment days. Cataracts can frequently develop if the eyes are not protected from UVB light exposure. To date, there is no link between an increase in a patient's risk of skin cancer and the proper use of narrow-band UVB phototherapy. "Proper use" is generally defined as reaching the "Sub-Erythemic Dose" (S.E.D.), the maximum amount of UVB your skin can receive "without" burning.
Certain fungal growths under the toenail can be treated using a specific wavelength of UV delivered from a high-power LED (light-emitting diode) and can be safer than traditional systemic drugs.
Infrared heater
Quartz heat lamps are used in food processing, chemical processing, paint drying, and thawing of frozen materials. They can also be used for comfort heating in cold areas, in incubators, and in other applications for heating, drying, and baking. During development of space re-entry vehicles, banks of quartz infrared lamps were used to test heat shield materials at power densities as high as 28 kilowatts/square foot (300 kW/m).
Infrared
Near-infrared light, or photobiomodulation, is used for treatment of chemotherapy-induced oral ulceration as well as wound healing. There is some work relating to anti-herpes virus treatment. Research projects include work on central nervous system healing effects via cytochrome c oxidase upregulation and other possible mechanisms.
Ultraviolet light therapy
Phototherapy for neonatal jaundice in infants uses blue light, not UV.
Radiation therapy
The precise treatment intent (curative, adjuvant, neoadjuvant therapeutic, or palliative) will depend on the tumor type, location, and stage, as well as the general health of the patient. Total body irradiation (TBI) is a radiation therapy technique used to prepare the body to receive a bone marrow transplant. Brachytherapy, in which a radioactive source is placed inside or next to the area requiring treatment, is another form of radiation therapy that minimizes exposure to healthy tissue during procedures to treat cancers of the breast, prostate and other organs. Radiation therapy has several applications in non-malignant conditions, such as the treatment of trigeminal neuralgia, acoustic neuromas, severe thyroid eye disease, pterygium, pigmented villonodular synovitis, and prevention of keloid scar growth, vascular restenosis, and heterotopic ossification. The use of radiation therapy in non-malignant conditions is limited partly by worries about the risk of radiation-induced cancers.
Laser safety
The eye focuses visible and near-infrared light onto the retina. A laser beam can be focused to an intensity on the retina which may be up to 200,000 times higher than at the point where the laser beam enters the eye. Most of the light is absorbed by melanin pigments in the pigment epithelium just behind the photoreceptors, and causes burns in the retina. Ultraviolet light with wavelengths shorter than 400 nm tends to be absorbed by lens and 300 nm in the cornea, where it can produce injuries at relatively low powers due to photochemical damage. Infrared light mainly causes thermal damage to the retina at near-infrared wavelengths and to more frontal parts of the eye at longer wavelengths. The table below summarizes the various medical conditions caused by lasers at different wavelengths, not including injuries due to pulsed lasers.
Infrared
Infrared radiation is popularly known as "heat radiation", but light and electromagnetic waves of any frequency will heat surfaces that absorb them. Infrared light from the Sun accounts for 49% of the heating of Earth, with the rest being caused by visible light that is absorbed then re-radiated at longer wavelengths. Visible light or ultraviolet-emitting lasers can char paper and incandescently hot objects emit visible radiation. Objects at room temperature will emit radiation concentrated mostly in the 8 to 25 µm band, but this is not distinct from the emission of visible light by incandescent objects and ultraviolet by even hotter objects (see black body and Wien's displacement law).
Infrared
A variety of technologies or proposed technologies take advantage of infrared emissions to cool buildings or other systems. The LWIR (8–15 µm) region is especially useful since some radiation at these wavelengths can escape into space through the atmosphere.
Light therapy
Light therapy uses either a light box which emits up to 10,000 lux of light at a specified distance, much brighter than a customary lamp, or a lower intensity of specific wavelengths of light from the blue (460 nm) to the green (525 nm) areas of the visible spectrum. A 1995 study showed that green light therapy at doses of 350 lux produces melatonin suppression and phase shifts equivalent to 10,000 lux white light therapy, but another study published in May 2010 suggests that the blue light often used for SAD treatment should perhaps be replaced by green or white illumination, because of a possible involvement of the cones in melatonin suppression.
High-energy visible light
Blue light within the range 400-450 nm has been reported in a number of studies to be effective as local treatment of eczema and psoriasis, as it purportedly helps dampen the immune response. Recent studies have also shown improvement of facial acne upon exposure to a LED emitting at 414 nm. A combination of exposure to red and blue lights is used more and more in clinical dermatologic therapies. Constructors such as Philips currently develop devices and techniques emitting in the blue visible spectrum to be used in dermatologic therapy.
Disinfectant
Ultraviolet germicidal irradiation is the use of high-intensity shortwave ultraviolet light for disinfecting smooth surfaces such as dental tools, but not porous materials that are opaque to the light such as wood or foam. Ultraviolet light is also used for municipal water treatment. Ultraviolet light fixtures are often present in microbiology labs, and are activated only when there are no occupants in a room (e.g., at night).
Lasers in cancer treatment
Laser-induced interstitial thermotherapy (LITT), or interstitial laser photocoagulation, also uses lasers to treat some cancers. LITT is similar to a cancer treatment called hyperthermia, which uses heat to shrink tumors by damaging or killing cancer cells. During LITT, an optical fiber is inserted into a tumor. Laser light at the tip of the fiber raises the temperature of the tumor cells and damages or destroys them. LITT is sometimes used to shrink tumors in the liver.
Multispectral image
In 2003, researchers at the United States Army Research Laboratory and the Federal Laboratory Collaborative Technology Alliance reported a dual band multispectral imaging focal plane array (FPA) was reported. This FPA allows researchers to look at two infrared (IR) planes at the same time. Multispectral imaging measures light emission and is often used in detecting or tracking military targets. Because mid wave infrared (MWIR) and long wave infrared (LWIR) technologies measure radiation inherent to the object and require no external light source, they also are referred to as thermal imaging methods.
Infrared heater
A heat lamp is an incandescent light bulb that is used for the principal purpose of creating heat. The spectrum of black body radiation emitted by the lamp is shifted to produce more infrared light. Many heat lamps include a red filter to minimize the amount of visible light emitted. Heat lamps often include an internal reflector.
Photoimmunotherapy
In Vitro studies showed that mAb-IR700 killed tumor cells seconds after the near-infrared light irradiation. There was also a positive correlation between the intensity of excitation light and percentage of cell death. Infrared light alone or mAb-IR700 conjugate alone did not cause any damage to normal cells. When tumor-xenografted mice were treated with mAb-IR700 and near-infrared light, significant tumor shrinkage was observed. With fractionated administration of mAB–IR700 conjugate followed by systematic repeated NIR light irradiation to the tumor, 80 percent of tumor cells were eradicated and the mice’s survival were significantly prolonged. Based on the current hypothesis, cell death induced by PIT was caused by rapid expansion of local water upon the formation of holes in the membrane.
Photothermal therapy
Unlike photodynamic therapy, photothermal therapy does not require oxygen to interact with the target cells or tissues. Current studies also show that photothermal therapy is able to use longer wavelength light, which is less energetic and therefore less harmful to other cells and tissues.
Blood irradiation therapy
It is used only for ultraviolet blood irradiation, that involves drawing blood out through a vein and irradiating it outside of the body. Though promoted as a treatment for cancer, a 1952 review in the "Journal of the American Medical Association" and another review by the American Cancer Society in 1970 concluded the treatment was ineffective. Stephen Barrett, writing for Quackwatch, lists ultraviolet blood irradiation therapy as a questionable treatment.
Acute lymphoblastic leukemia
Radiation therapy (or radiotherapy) is used on painful bony areas, in high disease burdens, or as part of the preparations for a bone marrow transplant (total body irradiation). In the past, physicians commonly utilized radiation in the form of whole-brain radiation for central nervous system prophylaxis, to prevent occurrence and/or recurrence of leukemia in the brain. Recent studies showed that CNS chemotherapy provided results as favorable but with less developmental side-effects. As a result, the use of whole-brain radiation has been more limited. Most specialists in adult leukemia have abandoned the use of radiation therapy for CNS prophylaxis, instead using intrathecal chemotherapy.
Image-guided radiation therapy
Radiation therapy is a local treatment that is designed to treat the defined tumour and spare the surrounding normal tissue from receiving doses above specified dose tolerances. There are many factors that may contribute to differences between the planned dose distribution and the delivered dose distribution. One such factor is uncertainty in patient position on the treatment unit. IGRT is a component of the radiation therapy process that incorporates imaging coordinates from the treatment plan to be delivered in order to ensure the patient is properly aligned in the treatment room.
Infrared heater
An infrared heater or heat lamp is a body with a higher temperature which transfers energy to a body with a lower temperature through electromagnetic radiation. Depending on the temperature of the emitting body, the wavelength of the peak of the infrared radiation ranges from to 1 mm. No contact or medium between the two bodies is needed for the energy transfer. Infrared heaters can be operated in vacuum or atmosphere.
Intense pulsed light
Intense pulsed light (IPL) is a technology used by cosmetic and medical practitioners to perform various skin treatments for aesthetic and therapeutic purposes, including hair removal, photorejuvenation (e.g. the treatment of skin pigmentation, sun damage, and thread veins) as well as to alleviate dermatologic diseases such as acne. IPL is increasingly used in optometry and ophthalmology as well, to treat evaporative dry eye disease due to meibomian gland dysfunction.
Auger therapy
Monochromatic X-rays may be channeled from synchrotron radiation, obtained from filtered Coolidge X-ray tubes or from the preferred transmission X-ray tubes. To induce inner-shell ionization with resonant scattering from a moderately-heavy atom with dozens of electrons, the X-ray photon energy must be 30 keV or higher to penetrate tissue in therapeutic applications. Although synchrotron radiation is extremely bright and monochromatic without thermal scattering, its brightness falls off at the fourth power of photon energy. At 15-20 kV or higher an X-ray tube with a molybdenum target, for example, could deliver as much X-ray fluence as a typical synchrotron. A Coolidge X-ray tube brightens by 1.7 kVp and synchrotron brightness decreases by 4 kV, implying that it is not useful for Auger therapy.
National Ignition Facility
One of the last steps in the process before reaching the target chamber is to convert the infrared (IR) light at 1053 nm into the ultraviolet (UV) at 351 nm in a device known as a frequency converter. These are made of thin sheets (about 1 cm thick) cut from a single crystal of potassium dihydrogen phosphate. When the 1053 nm (IR) light passes through the first of two of these sheets, frequency addition converts a large fraction of the light into 527 nm light (green). On passing through the second sheet, frequency combination converts much of the 527 nm light and the remaining 1053 nm light into 351 nm (UV) light. Infrared (IR) light is much less effective than UV at heating the targets, because IR couples more strongly with hot electrons which will absorb a considerable amount of energy and interfere with compression. The conversion process can reach peak efficiencies of about 80 percent for a laser pulse that has a flat temporal shape, but the temporal shape needed for ignition varies significantly over the duration of the pulse. The actual conversion process is about 50 percent efficient, reducing delivered energy to a nominal 1.8 MJ.
Fourier-transform infrared spectroscopy
FTIR is a method of measuring infrared absorption and emission spectra. For a discussion of "why" people measure infrared absorption and emission spectra, i.e. why and how substances absorb and emit infrared light, see the article: Infrared spectroscopy.
Cherenkov radiation
More recently, Cherenkov light has been used to image substances in the body. These discoveries have led to intense interest around the idea of using this light signal to quantify and/or detect radiation in the body, either from internal sources such as injected radiopharmaceuticals or from external beam radiotherapy in oncology. Radioisotopes such as the positron emitters F and N or beta emitters P or Y have measurable Cherenkov emission and isotopes F and I have been imaged in humans for diagnostic value demonstration. External beam radiation therapy has been shown to induce a substantial amount of Cherenkov light in the tissue being treated, due to the photon beam energy levels used in the 6 MeV to 18 MeV ranges. The secondary electrons induced by these high energy x-rays result in the Cherenkov light emission, where the detected signal can be imaged at the entry and exit surfaces of the tissue.
Indoor tanning
Certain skin conditions, including keratosis, psoriasis, eczema and acne, may be treated with UVB light therapy, including by using tanning beds in commercial salons. Using tanning beds allows patients to access UV exposure when dermatologist-provided phototherapy is not available. A systematic review of studies, published in "Dermatology and Therapy" in 2015, noted that moderate sunlight is a treatment recommended by the American National Psoriasis Foundation, and suggested that clinicians consider UV phototherapy and tanning beds as a source of that therapy.
Functional near-infrared spectroscopy
fNIRS is a non-invasive imaging method involving the quantification of chromophore concentration resolved from the measurement of near infrared (NIR) light attenuation or temporal or phasic changes. NIR spectrum light takes advantage of the optical window in which skin, tissue, and bone are mostly transparent to NIR light in the spectrum of 700–900 nm, while hemoglobin (Hb) and deoxygenated-hemoglobin (deoxy-Hb) are stronger absorbers of light. Differences in the absorption spectra of deoxy-Hb and oxy-Hb allow the measurement of relative changes in hemoglobin concentration through the use of light attenuation at multiple wavelengths. Two or more wavelengths are selected, with one wavelength above and one below the isosbestic point of 810 nm at which deoxy-Hb and oxy-Hb have identical absorption coefficients. Using the modified Beer-Lambert law (mBLL), relative concentration can be calculated as a function of total photon path length. Typically the light emitter and detector are placed ipsilaterally (each emitter/detector pair on the same side) on the subject's skull so recorded measurements are due to back-scattered (reflected) light following elliptical pathways.
Heat therapy
Infrared radiation is a convenient system to heat parts of our body. It has the advantage over direct contact in that radiation can heat directly the area where the blood capillaries and neuron terminals are. When heat comes from a direct contact source it has to heat the external layer of the skin, and heat is transferred to the deeper layer by conduction. Since heat conduction needs a temperature gradient to proceed, and there is a maximum temperature that can be safely used (around 42 °C), this means lower temperature where warming is needed.
Blood irradiation therapy
Historically, German doctors were the first to irradiate blood by UV lamps in the 1920s, and UVBI is widely spread in Germany so far. In the USA, this technique was best known during the Second World War.
Intravenous laser blood irradiation (a more effective and modern variant) was developed experimentally by the Russian researchers, Meshalkin and Sergievskiy, and introduced into clinical practice in 1981. Originally the method was applied in the treatment of cardiovascular abnormalities. but it is now used in the treatment of a wide range of diseases in select countries.
Infrared
Infrared radiation is emitted or absorbed by molecules when they change their rotational-vibrational movements. It excites vibrational modes in a molecule through a change in the dipole moment, making it a useful frequency range for study of these energy states for molecules of the proper symmetry. Infrared spectroscopy examines absorption and transmission of photons in the infrared range.
Photodisruption
Because the infrared laser is invisible to the surgeon's eye, typically a companion HeNe laser is used in conjunction. However, the eye lens acts as a prism, so the infrared light bends at a shallower angle than the red light, causing chromatic aberration. This means the area highlighted by the HeNe laser is not precisely the area being affected Nd:YAG laser, and therefore some surgical lasers have an added adjustment to compensate.
Commonly used gamma-emitting isotopes
In addition to their uses in radiography, both cobalt-60 (Co-60) and iridium-192 (Ir-192) are used in the radiotherapy of cancer. Cobalt-60 tends to be used in teletherapy units as a higher photon energy alternative to Cs-137, while iridium-192 tends to be used in a different mode of therapy, internal radiotherapy or brachytherapy. The iridium wires for brachytherapy are a palladium-coated iridium/palladium alloy wire made radioactive by neutron activation. This wire is then inserted into a tumor such as a breast tumor, and the tumor is irradiated by gamma ray photons from the wire. At the end of the treatment the wire is removed.
Gold nanoparticles in chemotherapy
A direct method of accessing and destroying tumour cells can be accomplished by photothermal cancer therapy or photodynamic therapy (PDT). This procedure is known to treat small tumours that are difficult to access and avoids the drawbacks (adverse effects) of conventional methods, including the unnecessary destruction of healthy tissues. The cells are destroyed by exposure to light, rupturing membranes causing the release of digestive enzymes. AuNPs have high absorption cross sections requiring only minimal input of irradiation energy. Human breast carcinoma cells infused with metal nanoparticles in vitro have been shown to have an "increase" in morbidity with exposure to near infrared (NIR). Short term exposure in vivo (4–6 minutes) to NIR had undergone the same effect. "Hirsch et al" observed that extreme heating in tumours would cause irreversible tissue damage including coagulation, cell shrinkage and loss of nuclear straining. Results of their in vivo nanoshell therapy of mice revealed penetration of the tumor ~5mm.The metal particles were tuned to high absorption and scattering, resulting in effective conversion of light into heat covering a large surface area.
The "El-Sayed group" studied AuNP effects in vitro and in vivo. They determined that the NIR wavelengths were converted into heat on the picosecond timescale, allowing for short exposure of CW to minimize possible exposure to healthy cells. In vitro, photothermal therapy was used in oral epithelial cell lines, (HSC 313 and HOC 3 Clone 8) and one benign epithelial cell line (HaCaT). El-Sayed "et al" found that the malignant cells that had undergone incubation in AuNPs conjugated with anti-epithelial growth factor receptor (EGFR) required half the energy to destroy a cell than a benign cell. Their material included gold coated silica nanoshells that could selectively absorb NIR waves. The particles were tuned by varying the thickness of the Au shell and changing the size of the silica core. In exposing these particles to NIR, the efficacy of Au was measured through the decrease of EFGR in oral squamous carcinoma cells.
Brachytherapy
Intraoperative radiation therapy (IORT) delivers radiation at the same time as the surgery to remove the tumour (lumpectomy). An applicator is placed in the cavity left after tumour removal and a mobile electronic device generates radiation (either x-rays or electrons) and delivers it via the applicator. Radiation is delivered all at once and the applicator removed before closing the incision.
Light therapy
Modern phototherapy lamps used in the treatment of seasonal affective disorder and sleep disorders either filter out or do not emit ultraviolet light and are considered safe and effective for the intended purpose, as long as photosensitizing drugs are not being taken at the same time and in the absence of any existing eye conditions. Light therapy is a mood altering treatment, and just as with drug treatments, there is a possibility of triggering a manic state from a depressive state, causing anxiety and other side effects. While these side effects are usually controllable, it is recommended that patients undertake light therapy under the supervision of an experienced clinician, rather than attempting to self-medicate.
Infrared astronomy
Like all other forms of electromagnetic radiation, infrared is utilized by astronomers to study the universe. Indeed, infrared measurements taken by the 2MASS and WISE astronomical surveys have been particularly effective at unveiling previously undiscovered star clusters. Examples of such embedded star clusters are FSR 1424, FSR 1432, Camargo 394, Camargo 399, Majaess 30, and Majaess 99. Infrared telescopes, which includes most major optical telescopes as well as a few dedicated infrared telescopes, need to be chilled with liquid nitrogen and shielded from warm objects. The reason for this is that objects with temperatures of a few hundred kelvins emit most of their thermal energy at infrared wavelengths. If infrared detectors were not kept cooled, the radiation from the detector itself would contribute noise that would dwarf the radiation from any celestial source. This is particularly important in the mid-infrared and far-infrared regions of the spectrum.
Chromotherapy
Color therapy is distinct from other types of light therapy, such as neonatal jaundice treatment and blood irradiation therapy which is a scientifically accepted medical treatment for a number of conditions, and from photobiology, the scientific study of the effects of light on living organisms. The potential risk of retinal damage linked to chromotherapy has been discussed by French skeptic and lighting physicist Sébastien Point. Although Point considers that LED lamps at domestic radiance are safe in normal use for the general population, 
he also pointed out the risk of overexposure to light from LEDs for practices like chromotherapy, when duration and time exposure are not under control.
Light therapy
Phototherapy can be effective in the treatment of eczema, atopic dermatitis, polymorphous light eruption, cutaneous T-cell lymphoma and lichen planus.
Narrowband UVB lamps, 311–313 nanometer is the most common treatment.
Light therapy
The Faroese physician Niels Finsen is believed to be the father of modern phototherapy. He developed the first artificial light source for this purpose. Finsen used short wavelength light to treat lupus vulgaris, a skin infection caused by "Mycobacterium tuberculosis". He thought that the beneficial effect was due to ultraviolet light killing the bacteria, but recent studies showed that his lens and filter system did not allow such short wavelengths to pass through, leading instead to the conclusion that light of approximately 400 nanometers generated reactive oxygen that would kill the bacteria. Finsen also used red light to treat smallpox lesions. He received the Nobel Prize in Physiology or Medicine in 1903. Scientific evidence for some of his treatments is lacking, and later eradication of smallpox and development of antibiotics for tuberculosis rendered light therapy obsolete for these diseases.
Forward-looking infrared
Infrared light falls into two basic ranges: "long-wave" and "medium-wave". Long-wave infrared (LWIR) cameras, sometimes called "far-infrared", operate at 8 to 12 μm and can see heat sources, such as hot engine parts or human body heat, several kilometers away. Longer-distance viewing is made more difficult with LWIR because the infrared light is absorbed, scattered, and refracted by air and by water vapor.
Infrared astronomy
The discovery of infrared radiation is attributed to William Herschel, who performed an experiment in 1800 where he placed a thermometer in sunlight of different colors after it passed through a prism. He noticed that the temperature increase induced by sunlight was highest "outside" the visible spectrum, just beyond the red color. That the temperature increase was highest at infrared wavelengths was due to the spectral response of the prism rather than properties of the Sun, but the fact that there was any temperature increase at all prompted Herschel to deduce that there was invisible radiation from the Sun. He dubbed this radiation "calorific rays", and went on to show that it could be reflected, transmitted, and absorbed just like visible light.
Infrared vision
The entire electromagnetic spectrum highlighting the infrared part located between the visible and the radio waves, is depicted in the figure. The IR spectrum can be subdivided into 5 regions, although this definition is somehow arbitrary and it differs from one author to another. The subdivision presented here is based on a combination of the atmospheric transmittance windows, i.e. the wavelengths regions in which infrared radiation is better transmitted through the atmosphere, the detector materials used to build the infrared sensors and the main applications. In this way, the Near Infrared (NIR) band is mostly used in fiber optic telecommunication systems since silica (SiO) provides a low attenuation losses medium for the infrared, whilst the Short Wave Infrared (SWIR) band allows to work on long-distance telecommunications (remote sensing) using a combinations of detector materials. The Medium Wavelength Infrared (MWIR) and the Long Wavelength Infrared (LWIR) bands find applications in Infrared Thermography for military or civil applications, e.g. target signature identification, surveillance, NonDestructive Evaluation, etc. The Very Long Wavelength Infrared (VLWIR) band is used in spectroscopy and astronomy.
Indium
Indium(III) oxide and indium tin oxide (ITO) are used as a transparent conductive coating on glass substrates in electroluminescent panels. Indium tin oxide is used as a light filter in low-pressure sodium-vapor lamps. The infrared radiation is reflected back into the lamp, which increases the temperature within the tube and improves the performance of the lamp.
Infrared heater
This heating technology is used in some expensive infrared saunas. It is also found in space heaters. These heaters use low watt density ceramic emitters (usually fairly big panels) which emit long wave infrared radiation. Because the heating elements are at a relatively low temperature, far-infrared heaters do not give emissions and smell from dust, dirt, formaldehyde, toxic fumes from paint-coating, etc. This has made this type of space heating very popular among people with severe allergies and multiple chemical sensitivity in Europe. Because far infrared technology does not heat the air of the room directly, it is important to maximize the exposure of available surfaces which then re-emit the warmth to provide an even all round ambient warmth.
Infrared
Infrared tracking, also known as infrared homing, refers to a passive missile guidance system, which uses the emission from a target of electromagnetic radiation in the infrared part of the spectrum to track it. Missiles that use infrared seeking are often referred to as "heat-seekers" since infrared (IR) is just below the visible spectrum of light in frequency and is radiated strongly by hot bodies. Many objects such as people, vehicle engines, and aircraft generate and retain heat, and as such, are especially visible in the infrared wavelengths of light compared to objects in the background.
Diabetic neuropathy
Monochromatic infrared photo energy treatment (MIRE) has been shown to be an effective therapy in reducing and often eliminating pain associated with diabetic neuropathy. The studied wavelength of 890 nm is able to penetrate into the subcutaneous tissue where it acts upon a specialized part of the cell called the cytochrome C. The infrared light energy prompts the cytochrome C to release nitric oxide into the cells. The nitric oxide in turn promotes vasodilation which results in increased blood flow that helps nourish damaged nerve cells. Once the nutrient rich blood is able to reach the affected areas (typically the feet, lower legs and hands) it promotes the regeneration of nerve tissues and helps reduce inflammation thereby reducing and/or eliminating pain in the area.
Cancer
Radiation therapy is used in about half of cases. The radiation can be either from internal sources (brachytherapy) or external sources. The radiation is most commonly low energy x-rays for treating skin cancers, while higher energy x-rays are used for cancers within the body. Radiation is typically used in addition to surgery and or chemotherapy. For certain types of cancer, such as early head and neck cancer, it may be used alone. For painful bone metastasis, it has been found to be effective in about 70% of patients.
Intraoperative radiation therapy
Early practitioners of IORT treated primarily abdominal malignancies using superficial x-rays (75-125 kV) and later orthovoltage x-rays (up to 300 kV in energy) prior to the advent of technology that enabled high energy electrons. For the first 75 years, X-Ray IORT was used mostly for palliation, but there were a few anecdotal reports of long-term survivors. In the early 1980s, when the use of electron IORT was increasing and showed promising results for certain indications, a handful of hospitals installed othovoltage units in lightly shielded ORs to see if this lower cost approach could achieve comparable results to that of electron IORT. This approach was less costly than building a shielded OR for an electron IORT unit and eliminated the logistics involved with patient transportation. However, it had a number of problems that limited its appeal. X-Ray IORT has a poor uniformity of dose as a function of depth of penetration, the radiation does not stop at a pre-defined depth but continues to deposit radiation to underlying structures, and can do damage to boney structures if too high a dose is delivered. Despite its long use (since the 1930s), less than 1000 patients have been treated with this approach, and it is no longer offered at most centers.
Infrared vision
Infrared vision is used extensively by the military for night vision, navigation, surveillance and targeting. For years, it developed slowly due to the high cost of the equipment and the low quality of available images. Since the development of the first commercial infrared cameras in the second half of the 1960s, however, the availability of new generations of infrared cameras coupled with growing computer power is providing exciting new civilian (and military) applications, to name only a few: buildings and infrastructure, works of art, aerospace components and processes, maintenance, defect detection and characterization, law enforcement, surveillance and public services, medical and veterinary thermal imaging. The electronic technique that uses infrared vision to "see" thermal energy, to monitor temperatures and thermal patterns is called infrared thermography.
Indocyanine green
ICG absorbs near infra-red, especially light with a wavelength of about 805 nanometers. A laser of that wavelength can penetrate tissue. That means, dying tissue with injected ICG allows an 800 nm-810 nm laser to heat or overheat the dyed tissue without harming the surrounding tissue. Although overheating is the main mechanism for it to kill cells, a small amount of the laser energy absorbed by the ICG releases free radicals such as singlet oxygen that also damage target cells.
Infrared
In the semiconductor industry, infrared light can be used to characterize materials such as thin films and periodic trench structures. By measuring the reflectance of light from the surface of a semiconductor wafer, the index of refraction (n) and the extinction Coefficient (k) can be determined via the Forouhi-Bloomer dispersion equations. The reflectance from the infrared light can also be used to determine the critical dimension, depth, and sidewall angle of high aspect ratio trench structures.
Thermographic camera
Infrared energy is just one part of the electromagnetic spectrum, which encompasses radiation from gamma rays, x-rays, ultra violet, a thin region of visible light, infrared, terahertz waves, microwaves, and radio waves. These are all related and differentiated in the length of their wave (wavelength). All objects emit a certain amount of black body radiation as a function of their temperature.
Generally speaking, the higher an object's temperature, the more infrared radiation is emitted as black-body radiation. A special camera can detect this radiation in a way similar to the way an ordinary camera detects visible light. It works even in total darkness because ambient light level does not matter. This makes it useful for rescue operations in smoke-filled buildings and underground.
D-Rev
Brilliance
Brilliance is a phototherapy device that treats neonatal Jaundice, or hyperbilirubinemia, a medical condition that affects 60% of newborns worldwide, 16.5% of whom suffer from severe that can lead to brain damage, nervous system damage (kernicterus), and death. Jaundice can be treated through phototherapy, which breaks down the excess bilirubin in a jaundiced newborn’s blood.
Brilliance uses high-intensity blue light-emitting diode () lights rather than the fluorescent tube lights used in traditional phototherapy devices. Brilliance LEDs last for ten years without needing replacement, while compact fluorescent light bulbs need to be replaced every four to six months. Brilliance is designed to help hospitals by eliminating the need for bulb replacements – saving hospitals money on compact fluorescent tube lights, and eliminating gaps in effective treatment caused by bulb supply. Tests at Stanford School of Medicine show that Brilliance performs on par or better than traditional Western phototherapy devices. Brilliance is priced to sell for $400 (22,000 INR).
Free-electron laser
Rox Anderson proposed the medical application of the free-electron laser in melting fats without harming the overlying skin. At infrared wavelengths, water in tissue was heated by the laser, but at wavelengths corresponding to 915, 1210 and 1720 nm, subsurface lipids were differentially heated more strongly than water. The possible applications of this selective photothermolysis (heating tissues using light) include the selective destruction of sebum lipids to treat acne, as well as targeting other lipids associated with cellulite and body fat as well as fatty plaques that form in arteries which can help treat atherosclerosis and heart disease.
Targeted intra-operative radiotherapy
The machine used for TARGIT is Intrabeam (Carl Zeiss, Germany). It is a miniature and mobile X-ray source which emits low energy X-ray radiation (max. 50 kV) in isotropic distribution. Due to the higher ionization density caused by soft X-ray radiation in the tissue, the relative biological effectiveness (RBE) of low-energy X-rays on tumour cells is higher when compared to high-energy X-rays or gamma rays which are delivered by linear accelerators. The radiation which is produced by mobile radiation systems has a limited range. For this reason, conventional walls are regarded sufficient to stop the radiation scatter produced in the operating room and no extra measures for radiation protection are necessary. This makes IORT for breast cancer by the TARGIT technique available in most operating rooms. The surgical technique is relatively simple but needs to be meticulously followed.
External beam radiotherapy
Image-guided radiation therapy (IGRT) augments radiotherapy with imaging to increase the accuracy and precision of target localization, thereby reducing the amount of healthy tissue in the treatment field. The more advanced the treatment techniques become in terms of dose deposition accuracy, the higher become the requirements for IGRT. In order to allow patients to benefit from sophisticated treatment techniques as IMRT or hadron therapy, patient alignment accuracies of 0.5 mm and less become desirable. Therefore, new methods like stereoscopic digital kilovoltage imaging based patient position verification (PPVS) to alignment estimation based on in-situ cone-beam computed tomography (CT) enrich the range of modern IGRT approaches.
Treatment of cancer
Radiation therapy (also called radiotherapy, X-ray therapy, or irradiation) is the use of ionizing radiation to kill cancer cells and shrink tumors. Radiation therapy can be administered externally via external beam radiotherapy (EBRT) or internally via brachytherapy. The effects of radiation therapy are localised and confined to the region being treated. Radiation therapy injures or destroys cells in the area being treated (the "target tissue") by damaging their genetic material, making it impossible for these cells to continue to grow and divide. Although radiation damages both cancer cells and normal cells, most normal cells can recover from the effects of radiation and function properly. The goal of radiation therapy is to damage as many cancer cells as possible, while limiting harm to nearby healthy tissue. Hence, it is given in many fractions, allowing healthy tissue to recover between fractions.
Irradiation
Irradiation is used in diagnostic imaging, cancer therapy and blood transfusion.
Ypsilanti State Hospital
Physiotherapy is a treatment that exposes the patient to ultra-violet and infrared lights. Some of these treatments included ultra-violet light, infrared light, electric bake, and diathermy. In 1937 the Ypsilanti State Hospital was introduced to several different shock therapies, including electric shock.
Light therapy
According to the American Cancer Society, there is some evidence that ultraviolet light therapy may be effective in helping treat certain kinds of skin cancer, and ultraviolet blood irradiation therapy is established for this application. However, alternative uses of light for cancer treatment – light box therapy and colored light therapy – are not supported by evidence. Photodynamic therapy (often with red light) is used to treat certain superficial non-melanoma skin cancers.
Indoor tanning
In 1890 the Danish physician Niels Ryberg Finsen developed a carbon arc lamp ("Finsen's light" or a "Finsen lamp") that produced ultraviolet radiation for use in skin therapy, including to treat lupus vulgaris. He won the 1903 Nobel Prize in Physiology or Medicine for his work.
Lasers in cancer treatment
Photodynamic therapy (PDT) is another type of cancer treatment that uses lasers. In PDT, a certain drug, called a photosensitizer or photosensitizing agent, is injected into a patient and absorbed by cells all over the patient’s body. After a couple of days, this agent is found mostly in cancer cells. Laser light is then used to activate the agent and destroy cancer cells. Because the photosensitizer makes the skin and eyes sensitive to light afterwards, patients are advised to avoid direct sunlight and bright indoor light during that time.
Infrared lamp
Incandescent light bulbs use a tungsten filament heated to high temperature to produce visible light and, necessarily, even more infrared radiation. Round bulbs, often tinted red to reduce visible light, provide infrared radiant heat suitable for warming of people or animals, but the power density available is low. The development of quartz halogen linear lamps allowed much higher power density up to 200 watts/inch of lamp (8 w/mm), useful for industrial heating, drying and processing applications.
By adjusting the voltage applied to incandescent lamps, the spectrum of the radiated energy can be made to reduce visible light and emphasize infrared energy production. Different wavelengths of infrared radiation are differently absorbed by different materials.
Capnography
Capnographs usually work on the principle that absorbs infrared radiation. A beam of infrared light is passed across the gas sample to fall on a sensor. The presence of in the gas leads to a reduction in the amount of light falling on the sensor, which changes the voltage in a circuit. The analysis is rapid and accurate, but the presence of nitrous oxide in the gas mix changes the infrared absorption via the phenomenon of collision broadening. This must be corrected for measuring the in human breath by measuring its infrared absorptive power. This was established as a reliable technique by John Tyndall in 1864, though 19th and early 20th century devices were too cumbersome for everyday clinical use.
Infrared sauna
Some infrared therapy proponents claim that the IR is an effective method for considerably raising the rate of energy expenditure in the body. Proponents typically quote the "Journal of the American Medical Association" stating: "A moderately conditioned person can easily sweat off 500 grams in an infrared room, consuming nearly 300 kcal, which is equivalent to running 2–3 miles. A heat-conditioned person can easily sweat off 600–800 kcal with no adverse effects. While the weight of the water loss can be regained by drinking water, the calories consumed will not be." However, this conclusion drew significant criticism, at least because it implies that individuals living in warm climates, where liters of sweat are generated per day, would require hundreds or thousands of additional kilocalories to survive, which is known not be the case.
Inpainting
In photography and cinema, it is used for film restoration, to reverse the deterioration (e.g., cracks in photographs or scratches and dust spots in film; see infrared cleaning). It is also used for removing red-eye, the stamped date from photographs and removing objects to creative effect.