TY - JOUR
T1 - Response corrections for solid-state detectors in megavoltage photon dosimetry
AU - Yin, Zaizhe
AU - Hugtenburg, Richard
AU - Beddoe, Alun
PY - 2004/8/21
Y1 - 2004/8/21
N2 - Solid-state detectors offer high sensitivity, stability and resolution and are frequently the dosimeter of choice for on-line dosimetry and small field therapies such as stereotactic radiosurgery. The departure from tissue equivalence of many solid-state devices, including diodes and MOSFETs, has to be carefully considered at lower energies and for Compton scattered radiation where the strongly Z-dependent photoelectric effect is significant. A modification of Burlin cavity theory is proposed that treats primary and scatter photon spectra separately and this has been applied to determine the correction factors for diode detector measurements of 6 and 15 MV linear accelerator beams. Uncorrected, an unshielded diode overestimates the dose at depth by as much as 15% for the 6 MV beam. The model predicts the effect to within 1% for both energies offering a basis for the correction of diodes for use in routine dosimetry.
AB - Solid-state detectors offer high sensitivity, stability and resolution and are frequently the dosimeter of choice for on-line dosimetry and small field therapies such as stereotactic radiosurgery. The departure from tissue equivalence of many solid-state devices, including diodes and MOSFETs, has to be carefully considered at lower energies and for Compton scattered radiation where the strongly Z-dependent photoelectric effect is significant. A modification of Burlin cavity theory is proposed that treats primary and scatter photon spectra separately and this has been applied to determine the correction factors for diode detector measurements of 6 and 15 MV linear accelerator beams. Uncorrected, an unshielded diode overestimates the dose at depth by as much as 15% for the 6 MV beam. The model predicts the effect to within 1% for both energies offering a basis for the correction of diodes for use in routine dosimetry.
UR - http://www.scopus.com/inward/record.url?scp=4444263965&partnerID=8YFLogxK
U2 - 10.1088/0031-9155/49/16/015
DO - 10.1088/0031-9155/49/16/015
M3 - Article
C2 - 15446798
VL - 49
SP - 3691
EP - 3702
JO - Physics in Medicine and Biology
JF - Physics in Medicine and Biology
ER -