Embedded radiation emitter for the localization and dosimetry of brachytherapy seed implants

A device for delivering ionizing radiation to mammalian tissue, comprising:

• (a) a therapeutic isotope that emits ionizing radiation suitable for treating neoplastic tissues;
• and
• (b) a marker isotope capable of emitting identifiable radiation to allow detection of the location or dosimetry or both of said device;
• wherein:
• (c) the size and shape of said device are adapted for insertion into mammalian tissue;
• (d) the quantity, kind, and distribution of said therapeutic isotope in said device are adapted to deliver therapeutic amounts of ionizing radiation to tissue locally, in the vicinity of said device, but not to deliver substantial amounts of ionizing radiation to other parts of the body;
• (e) the quantity, kind, and distribution of said marker isotope in said device are adapted not to deliver substantial amounts of radiation beyond the region in which said therapeutic isotope delivers substantial amounts of ionizing radiation;
• (f) the quantity, kind, and distribution of said marker isotope in said device are adapted to emit a sufficient quantity and energy of radiation at a sufficient distance from said device that one or more radiation detectors external to the body can determine the location of said device, or can infer the dosimetry resulting from the therapeutic isotope as a function of the radiation detected from the marker isotope or both;
• and
• (g) said therapeutic isotope and said marker isotope are different.