Patent ID: 8827884

Claim:
A radioactive seed for use in oncology therapy, the radioactive seed comprising: a radioactive material including at least one radioisotope; and a biodegradable host in which the radioactive material is disposed, the biodegradable host configured to biodegrade over a therapy time period when implanted in an oncology subject; wherein the radioactive material defines a radioactive core and the biodegradable host defines a biodegradable encapsulant surrounding the radioactive core; wherein the biodegradable encapsulant is absorbing for at least one type of radiation emitted by the radioactive material to control the radiation versus time delivered to the oncology subject by radiation absorption that varies with time as the biodegradable encapsulant degrades over the therapy time period when implanted in the oncology subject; wherein the at least one radioisotope has a half life that is shorter than a time period for the biodegradable host to biodegrade when implanted in the oncology subject, the half life of the at least one radioisotope respective to the time period for the biodegradable host to biodegrade being effective for the biodegradable host to hold the radioactive material in place at a target location in the oncology subject for the therapy time period, after which biodegradation of the biodegradable host releases the radioactive material; and wherein the radioactive seed is configured by the biodegradable encapsulant to have radiation output at a time of implantation that is lower than a peak radiation output that occurs at a time after the time of implantation.