Details

Autor(en) / Beteiligte

• Austerlitz, C.
• Mota, H.
• Almeida, C. E.
• Allison, R.
• Sibata, C.
• Universidade Estadual do Rio de Janeiro, Rua Sao Franciso Xavier, 524-Maracana, Rio de Janeiro, RJ
• Brody School of Medicine, East Carolina University, Department of Radiation Oncology, 600 Moye Boulevard, Greenville, North Carolina 27858

Titel

Quality assurance of HDR {sup 192}Ir sources using a Fricke dosimeter

Ist Teil von

• Medical physics (Lancaster), 2007-04, Vol.34 (4)

Ort / Verlag

United States

Erscheinungsjahr

2007

Quelle

Wiley Online Library

Beschreibungen/Notizen

• A prototype of a Fricke dosimetry system consisting of a 15x15x15 cm{sup 3} water phantom made of Plexiglas registered and a 11.3-ml Pyrex balloon fitted with a 0.2 cm thick Pyrex sleeve in its center was created to assess source strength and treatment planning algorithms for use in high dose rate (HDR) {sup 192}Ir afterloading units. In routine operation, the radioactive source is positioned at the end of a sleeve, which coincides with the center of the spherical balloon that is filled with Fricke solution, so that the solution is nearly isotropically irradiated. The Fricke system was calibrated in terms of source strength against a reference well-type ionization chamber, and in terms of radial dose by means of an existing algorithm from the HDR's treatment planning system. Because the system is based on the Fricke dosimeter itself, for a given type and model of {sup 192}Ir source, the system needs initial calibration but no recalibration. The results from measurements made over a 10 month period, including source decay and source substitutions, have shown the feasibility of using such a system for quality control (QC) of HDR afterloading equipment, including both the source activity and treatment planning parameters. The benefit of a large scale production and the use of this device for clinical HDR QC audits via mail are also discussed.