Inhalation of beta radioactive isotopes may cause beta burns of lungs and nasopharyngeal region, ingestion may lead to burns of gastrointestinal tract; the latter being a risk especially for grazing animals. In first degree beta burns the damage is largely limited to epidermis. Dry or wet desquamation occurs; dry scabs are formed, then heal rapidly, leaving a depigmented area surrounded with irregular area of increased pigmentation. The skin pigmentation returns to normal within several weeks. Second degree beta burns lead to formation of blisters. Third and fourth degree beta burns result in deeper, wet ulcerated lesions, which heal with routine medical care after covering themselves with dry scab. In case of heavy tissue damage, ulcerated necrotic dermatitis may occur. Pigmentation may return to normal within several months after wound healing.Lost hair begins regrowing in nine weeks and is completely restored in about half a year.The acute dose-dependent effects of beta radiation on skin are as follows:
According to other source:
As shown, the dose thresholds for symptoms vary by source and even individually. In practice, determining the exact dose tends to be difficult. Similar effects apply to animals, with fur acting as additional factor for both increased particle retention and partial skin shielding. Unshorn thickly wooled sheep are well protected; while the epilation threshold for sheared sheep is between 23 and 47 Gy (2500–5000 rep) and the threshold for normally wooled face is 47–93 Gy (5000–10000 rep), for thickly wooled (33 mm hair length) sheep it is 93–140 Gy (10000–15000 rep).
The energy-depth-dose profile is a curve starting with a surface dose, ascending to the maximum dose in a certain depth dm (usually normalized as 100% dose), then descends slowly through depths of 90% dose (d90) and 80% dose (d80), then falls off linearly and relatively sharply though depth of 50% dose (d50). The extrapolation of this linear part of the curve to zero defines the maximum electron range, Rp. In practice, there is a long tail of weaker but deep dose, called "bremsstrahlung tail", attributable to bremsstrahlung. The penetration depth depends also on beam shape, narrower beam tend to have less penetration. In water, broad electron beams, as is the case in homogeneous surface contamination of skin, have d80 about E/3 cm and Rp about E/2 cm, where E is the beta particle energy in MeV.The penetration depth of lower-energy beta in water (and soft tissues) is about 2 mm/MeV. For a 2.3 MeV beta the maximum depth in water is 11 mm, for 1.1 MeV it is 4.6 mm. The depth where maximum of the energy is deposited is significantly lower.The energy and penetration depth of several isotopes is as follows:
For a wide beam, the depth-energy relation for dose ranges is as follows, for energies in megaelectronvolts and depths in millimeters. The dependence of surface dose and penetration depth on beam energy is clearly visible. Causes
Radiation burns are caused by exposure to high levels of radiation.