Bioevaluation of (125) I Ocu-Prosta seeds for application in prostate cancer brachytherapy

In recent years, brachytherapy involving permanent radioactive seed implantation has emerged as an effective modality for the management of cancer of prostate. 125 I-Ocu-Prosta seeds were indigenously developed and studies were carried out to assess the safety of the indigenously developed 125 I-Ocu-Prosta seeds for treatment of prostate cancer.

Animal experiments were performed to assess the likelihood of in vivo release of 125 I from radioactive seeds and migration of seeds implanted in the prostate gland of the rabbit. In vivo release of 125 I activity was monitored by serial blood sampling from the auricular vein and subsequent measurement of 125 I activity. Serial computed tomography (CT) scans were done at regular intervals till 6 months post implant to assess the physical migration of the seeds.

The laser welded seeds maintained their hermeticity and prevented the in vivo release of 125 I activity into the blood as no radioactivity was detected during follow up blood measurements. Our study showed that the miniature 125 I seeds were clearly resolved in CT images. Seeds remained within the prostate gland during the entire study period. Moreover, the seed displacement was minimal even within the prostate gland.

Our findings have demonstrated that indigenously developed 125 I-Ocu-Prosta seeds may be suitable for application in treatment of prostate cancer.