1. Field of the Invention
The present invention relates to a medical capsule for conducting sampling of a humor or dosage of a medicine at a desired location inside a living body. The present invention also is concerned with an apparatus for activating such a medical capsule from the outside of the living body.
2. Description of the Prior Art
Hitherto, a medical capsule has been known as a device which conducts sampling of, for example, intestinal liquid, or dosage of a medicine at a predetermined location in a living body, for the purpose of diagnosis or medical treatment.
The medical capsule has a capsule-like hermetic casing having an openable portion. When such a medical capsule swallowed by a patient has reached a predetermined position inside the patient's body, the openable portion is opened so as to sample a humor such as a gastric juice or to dose a medicine charged in the capsule. Then, the capsule is discharged through anus of the patient and collected. Such a medical capsule is disclosed, for example, in Japanese Patent Publication Nos. 53-53182, 55-9033. 55-49853, 57-1255, 57-39776 and 61-11104.
This medical capsule is very small and can easily swallow without any pain and, hence, is attracting attention in the medical fields. In particular, the medical capsule, when used for the purpose of dosage, can directly dose the medicine to the affected part of the body, thus attaining a great medical treating effect. For instance, when this capsule is used against a cancer in an alimentary system, a remarkable carcinostatic effect without side-effect, thus offering a desired treating effect.
A known medical capsule for sampling will be described in more detail. As shown in FIG. 10, a medical capsule used for the sampling purpose has a hermetic casing 103 composed of a frame 101 and an outer cylinder 102. A piston 104 is movably received in the outer cylinder 102. As the piston 104 is moved, a vacuum region is produced in the outer cylinder 102 so that a gastric juice around the casing is sucked into the capsule through ports 105, 106, whereby the sampling of the gastric juice is conducted. This medical capsule for sampling is disclosed in Japanese Utility Model Publication No. 57-57684.
The piston 104 in this medical capsule operates by the springing force of a spring 107. Initially, the spring 107 is compressed and held in the compressed state by a fixing thread 108. After the capsule is swallowed by a patient, the position of the capsule is traced and monitored by an external monitoring device such as a roentgen apparatus. When the capsule has reached a predetermined position inside the body, a resonance of a resonance circuit is caused by an externally given radio wave so as to supply an electrical current to a filament 109. The fixing thread 108 is then molten by the heat generated by the filament 109 so that the piston 104 is projected by the resilient force of the spring 107, whereby the capsule sucks a gastric juice to complete the sampling.
FIG. 11 illustrates a known medical capsule used for the purpose of dosage. This capsule has a medicine chamber 110 in one end of which a piston 104 is received slidably, whereas a discharge port 112 formed in the other end of the medicine chamber 110 is normally closed by a plug 111. This medical capsule is disclosed, for example, in Japanese Patent Publication No. 55-49853. Other portions are materially the same as those of the medical capsule shown in FIG. 10. For information, the same reference numerals are used to denote the same parts as those appearing in FIG. 10 and the description of such parts is omitted herein.
In operation, the fixing thread 108 is cut by the same method as that described before, so that the piston 104 moves inside the outer cylinder 102 so that the medicine Y in the medicine chamber is pressurized to forcibly remove the plug 111 so as to be discharged from the capsule.
Various other methods have been proposed for externally activating medical capsules. For instance, the following four methods have been proposed.