Shielding design for a Cs-137 rod-type standard point source for well chamber constancy checks.
Well type chambers are used for radioactive source calibrations in brachytherapy, but do not provide radiation shielding. Routine constancy checks on a well chamber are required between periodic secondary standard laboratory calibrations to ensure consistent device performance, and ultimately to ensure accurate patient dose delivery. In this work, a method is described to provide suitable shielding for a Cs-137 rod-type point source to enable use for constancy checks. A novel plunger-type shielded housing was designed and constructed for the Cs-137 source that when combined with a suitably shielded well-chamber container minimised user exposure during constancy checks. The designed shielding proved effective, and a constancy test routine was established and used for the past 16 months. The well chamber showed consistent performance (0.12 ± 0.18 % from the baseline) and no increased exposure was reported on users' radiation badges.
Department of Radiation Oncology, Sir Charles Gairdner Hospital, Nedlands, WA, 6009, Australia. Mahsheed.Sabet@health.wa.gov.au.
Mahsheed
M
Sabet
Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Nedlands, WA, 6009, Australia.
David
D
Cryer
Department of Radiation Oncology, Sir Charles Gairdner Hospital, Nedlands, WA, 6009, Australia.
David
D
Waterhouse
D001918:Brachytherapy / Q000379:methods*; D002588:Cesium Radioisotopes / Q000737:chemistry*; D004867:Equipment Design; D011835:Radiation Protection / Q000295:instrumentation*; D012015:Reference Standards
D002588:Cesium Radioisotopes
Constancy test; Cs-137 standard source; Shielding; Well chamber