The use of thermoluminescent dosimeters for In-vivo dosimetry in a fast neutron therapy beam
Master Thesis
2000
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University of Cape Town
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Abstract
Thermoluminescent detectors (TLD-700) have been investigated for absorbed dose measurements in a p(66)/Be neutron therapy beam at the National Accelerator Centre. Chips were selected based on their reproducibility and chip individual neutron calibration factors were derived. The dose non-linearity was determined in peak 5 and peak 6 and dose non-linearity corrections were performed. The sensitivity of TLD-700 chips with depth and off-axis distance was determined. In-vivo dose measurements were performed on seven patients (9 fields). In the entrance in-vivo dose measurements, a maximal deviation of 3.2 % was detected and a systematic difference of 1.7 % was observed. On the exit side, a maximal deviation of -7.3 % was detected and a systematic difference of -5.1 % was observed. The glow curve peak 6/5 ratio was investigated and found to correlate with the qualitative variations of the average LET in the neutron beam.
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Bibliography: leaves 72-77.
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Reference:
Bhengu, K. 2000. The use of thermoluminescent dosimeters for In-vivo dosimetry in a fast neutron therapy beam. University of Cape Town.