title: Template-guided interstitial implants: Cs-137 reusable sources as a substitute for Ir-192.
abstract: Template-guided implantation of rigid steel or plastic guide needles for afterloading of radioactive sources is widely used in the treatment of gynecologic, rectal, and urologic malignant neoplasms. Iridium-192 is used almost universally, despite the high cost per implant, due to its short half-life and limited need for a flexible, trimmable source. A reusable afterloading system containing cesium-137 was developed. Each source has an effective active length of 6.8 cm and is encapsulated at the distal end of a 21-cm-long stainless steel tube. The sources can be afterloaded into the same plastic guide needles normally used for Ir-192 ribbons. Physical and dosimetric aspects of these sources are compared with those of Ir-192, and radiation protection and cost effectiveness are also discussed.
mesh_terms: D001918:Brachytherapy / Q000191:economics / Q000295:instrumentation*; D002588:Cesium Radioisotopes / Q000627:therapeutic use*; D003362:Cost-Benefit Analysis; D004867:Equipment Design; D006801:Humans; D007495:Iridium / Q000627:therapeutic use*; D009010:Monte Carlo Method; D009339:Needles; D010969:Plastics; D011835:Radiation Protection / Q000295:instrumentation; D011868:Radioisotopes / Q000627:therapeutic use*; D011874:Radiometry; D011879:Radiotherapy Dosage; D013232:Steel
chemical_list: D002588:Cesium Radioisotopes; D010969:Plastics; D011868:Radioisotopes; D013232:Steel; D007495:Iridium