Use of a Radiotherapy Treatment-Planning Computer for Dosimetry of the AFRRI (Armed Forces Radiobiology Research Institute) Cobalt-60 Facility.
ARMED FORCES RADIOBIOLOGY RESEARCH INST BETHESDA MD
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This study examined the feasibility of using radiation therapy treatment-planning computer TPC designed for clinical radiotherapy, to calculate patterns of depth dose and tissue-to-air ratios TARs for objects irradiated in the Cobalt-60 Facility at the Armed Forces Radiobiology Research Institute AFRRI. The TPC was used to calculate patterns of depth dose for four cylindrical phantoms of different sizes. Patterns of whole-body depth dose and TARs were calculated for cylindrical phantoms using a computer for treatment planning, and then compared to those measured in the Cobalt-60 Facility. The measured TARs agreed well with the computer-calculated TARs for one computational mode but not for another. The calculated and experimental depth-dose patterns agreed well at the central cross sections of the phantoms, but differed significantly at the cross sections near the end of the phantoms. These data demonstrate the degree of nonuniformity of dose in cylindrical phantoms irradiated in the Cobalt-60 Facility. They also point out the usefulness of a treatment-planning computer in characterizing distributions of depth dose.
- Medicine and Medical Research