Application of IAEA TRS-398 Protocol to Gamma Knife Model C.
- Author:
Hyun Tai CHUNG
1
Author Information
1. Department of Neurosurgery, Seoul National University Hospital, Seoul, Korea. htchung@korea.com
- Publication Type:Original Article
- Keywords:
Gamma knife;
Absorbed dose to water;
IAEA TRS-398;
Water phantom
- MeSH:
Nuclear Energy;
Plastics;
Radiotherapy;
Water
- From:Korean Journal of Medical Physics
2007;18(4):194-201
- CountryRepublic of Korea
- Language:Korean
-
Abstract:
Although Gamma Knife irradiates much more radiation in a single session than conventional radiotherapy, there were only a few studies to measure absolute dose of a Gamma Knife. Especially, there is no report of application of International Atomic Energy Agency (IAEA) TRS-398 which requires to use a water phantom in radiation measurement to Gamma Knife. In this article, the authors reported results of the experiments to measure the absorbed dose to water of a Gamma Knife Model C using the IAEA TRS-398 protocol. The absorbed dose to water of a Gamma Knife model C was measured using a water phantom under conditions as close as possible to the IAEA TRS-398 protocol. The obtained results were compared with values measured using the plastic phantom provided by the Gamma Knife manufacturer. Two Capintec PR-05P mini-chambers and a PTW UNIDOS electrometer were used in measurements. The absorbed dose to water of a Gamma Knife model C inside the water phantom was 1.38% larger than that of the plastic phantom. The current protocol provided by the manufacturer has an intrinsic error stems from the fact that a plastic phantom is used instead of a water phantom. In conclusion, it is not possible to fully apply IAEA TRS-398 to measurement of absorbed dose of a Gamma Knife. Instead, it can be a practical choice to build a new protocol for Gamma Knife or to provide a conversion factor from a water phantom to the plastic phantom. The conversion factor can be obtained in one or two standard laboratories.
