referring to the drawings in detail wherein like numerals indicate like elements , reference numeral 1 refers to a generally rectangular patch constructed in accordance with the present invention . radioactive seeds 10 are threaded according to a predetermined pattern into a plastic mesh 20 such as &# 34 ; marlex &# 34 ;® which is a polypropylene mesh . the mesh 20 containing the seeds 10 is then embedded in a nonabsorbable silicone 30 , such as &# 34 ; silastic &# 34 ;®. the &# 34 ; silastic &# 34 ;® 30 fixes the seeds 10 within the mesh 20 and permanently prevents their displacement even when the mesh 20 is flexed over curved surfaces . another type of plastic which could be used in place of the &# 34 ; marlex &# 34 ;®, is &# 34 ; goretex &# 34 ;®. the seeds 10 could be threaded into a &# 34 ; goretex &# 34 ;® mesh 20 just as well and the entirety enclosed in &# 34 ; silastic &# 34 ;® 30 . the choice of the &# 34 ; marlex &# 34 ;® was due to it being more of a mesh and more easily threadable . it is also far cheaper and more generally available . all three materials , i . e ., &# 34 ; silastic &# 34 ;®, &# 34 ; marlex &# 34 ;®, and &# 34 ; goretex &# 34 ;®, are nonabsorbable and have been approved by the fda for biological use . they are used widely . for example , a standard repair for hernias , the most common surgical operation , involves the use of &# 34 ; marlex &# 34 ;® or &# 34 ; goretex &# 34 ;® as a reinforcing layer and thousands of these patches have been used throughout the world . the &# 34 ; silastic &# 34 ;® 30 embedding guarantees that the seeds 10 will not move . this is the criticism of the horowitz patch which is made up of an absorbable compound . the horowitz material is resorbed at various rates within the body , usually a matter of months . yet the seeds remain active and radiation continues for a year or more . it is possible that with absorption of the material or even partial absorption of the material some of the seeds would be free to move around and create a concentration of radiation in one spot and a lack of radiation in another thus causing both dangers or local overdosage and areas of inadequate treatment . the seeds 10 used in this invention are iodine - 125 seeds and range from 4 . 2 to 4 . 9 mm in length and from 0 . 77 to 0 . 96 mm in diameter . the shell material 11 is titanium tubing having a wall thickness of 0 . 05 mm with welds at both ends 12 . the seed 10 used in the preferred embodiment contains within it a silver rod 13 serving both as an x - ray marker and a carrier for iodine - 125 . iodine - 125 has a half - life of 59 . 6 days . the energy of the iodine - 125 is 27 - 35 kev and has a half value in a tissue layer of 2 cm . the method which would be followed for use of the invention is as follows . the exact location and extent of the tumor is determined . the tumor is surgically removed . following removal of the tumor , a sterile , nonabsorbable radioactive seed patch 1 is tailored , positioned and sutured over the region where there may be remaining cancer cells . the patch 1 will be permanent and would not be removed unless necessary . a postmortem performed on the first patient who received the radioactive seed patch implant indicated that there were no adverse effects from the implant . the patient had a tumor removed in the head of the pancreas and the patch implanted over the resected area . the patient died from liver complications related to pancreatic carcinoma . fig1 is a face view of the radioactive seed patch 1 in a shielded container 2 prior to its use in surgery . as may be seen from this figure , the side edges 21 of the mesh 20 have not been embedded in silicone 30 . the silicone embedding procedure is accomplished directly in the shielded container 2 itself prior to shipment . the portion of the mesh 20 not embedded in silicone is cut off before implanting . fig4 is an x - ray of a patient with a radioactive seed patch 1 implanted . because of the silver rod 13 within each seed 10 , the seeds 10 are readily visible on the x - ray . fig5 is a cross section cat scan of the same patient . visible for orientation purposes is the patient &# 39 ; s liver 4 , spleen 5 , spine 6 , and the pancreas 7 . it may be noted that the right lobe 8 of the pancreas 7 has been removed . a radioactive seed patch 1 was implanted over the surgical removed area . the radioactive seeds 10 may be seen . other embodiments may be readily devised by those skilled in the art which will embody the principles of the invention and fall within the spirit and scope thereof . in one variation the seeds may be replaced with radioactive threads 15 threaded through the mesh 20 .