Midplane dose determination and verification of calculated doses in total body irradiation

OBJECTIVES To compare calculated and measured doses for different regions of anthropomorphic phantom and patients using ion chamber and thermoluminescence dosimetry (TLD) for total body irradiation. METHODS Measurements were done for lateral fields with 6 MV, gantry 82 degrees, 40x40 cm(2) field and 400 cm source-axis distance (SAD). Entrance-exit and midline doses were measured on anthropomorphic phantom by TLD and entrance-exit doses were measured by TLD and ion chamber on patients. RESULTS For anthropomorphic phantom measurements differences between calculated and measured entrance-exit doses of head, neck, shoulder, lung and thick pelvis were 0.8%, 2.7%, 26.4%, 4.4% and 4.9% and for midline doses were 1.6%, 1.6%, 6.3%, -1.4% and 7.4% respectively. For patients; TLD differences were within -4.13% ile 6.7%, -3.3% ile 3.9%, 5.1% ile 16.6%, -7.8% ile 2.4%, and 3.6% ile 7.1% respectively. For thick pelvis measurements with ion chamber differences were within %00.1-1.9. CONCLUSION Total body irradiation is being applied in limit values in our clinic.