A measuring system with a recombination chamber for neutron dosimetry around medical accelerators.
A measuring system for dosimetry of neutrons generated around medical electron accelerators is proposed. The system consists of an in-phantom tissue-equivalent recombination chamber and associated electronics for automated control and data acquisition. A second ionization chamber serves as a monitor of photon radiation. Two quantities are determined by the recombination chamber--the total absorbed dose and the recombination index of radiation quality. The ambient dose equivalent, H*(10), or neutron absorbed dose in an appropriate phantom, can be then derived from the measured values. Tests of the system showed that a 0.5% dose contribution of neutrons to the absorbed dose of photons could be detected and estimated under laboratory conditions. Preliminary tests at the 15 MV Varian Clinac 2300C/D medical accelerator confirmed that the measuring system could be used under clinical conditions. The H*(10) of the mixed radiation was determined with an accuracy of approximately 10%.
Golnik
N
N
Institute of Precision and Biomedical Engineering, Warsaw University of Technology, PL 02-525 Warsaw, Poland. golnik@mech.pw.edu.pl
Kamiński
P
P
Zielczyński
M
M
D001822:Body Burden; D004781:Environmental Exposure / Q000032:analysis; D004867:Equipment Design; D019544:Equipment Failure Analysis / Q000379:methods; D018499:Linear Energy Transfer; D009502:Neutrons; D009683:Nuclear Medicine / Q000379:methods; D016273:Occupational Exposure / Q000032:analysis*; D010315:Particle Accelerators; D011829:Radiation Dosage; D011835:Radiation Protection / Q000295:instrumentation* / Q000379:methods; D011868:Radioisotopes / Q000032:analysis*; D011874:Radiometry / Q000295:instrumentation* / Q000379:methods; D011878:Radiotherapy / Q000295:instrumentation*; D012062:Relative Biological Effectiveness; D015203:Reproducibility of Results; D012542:Scattering, Radiation; D012680:Sensitivity and Specificity; D014159:Transducers
D011868:Radioisotopes