Electron energy constancy verification using a double-wedge phantom.
Routine constancy checks of electron energy are often time consuming because of the necessity to measure a dose at two depths. A technique is described that uses a double-wedge shaped phantom positioned on a Profiler diode array for measuring an electron energy constancy metric similar to R(50). The double-wedge electron profiles are invariant to phantom alignment in the wedge direction, unlike single wedge techniques, and the sensitivity of the technique is similar to water-based depth-dose measurements over an energy range of 6 to 20 MeV. Reproducibility results ranging from 0.01 to 0.03 cm were achieved for measurements taken over the course of 1.5 yrs. The technique is efficient in that only one phantom setup is required for all electron energies.
Wells
Derek M
DM
Department of Medical Physics, British Columbia Cancer Agency-Vancouver Island Centre, 2410 Lee Avenue, Victoria, British Columbia, Canada V8R 6V5. dwells@bccancer.bc.ca
Picco
Philip J
PJ
Ansbacher
Will
W
D002138:Calibration; D004583:Electrons; D019047:Phantoms, Imaging; D011786:Quality Control; D011834:Radiation Monitoring; D011879:Radiotherapy Dosage / Q000592:standards; D011880:Radiotherapy Planning, Computer-Assisted / Q000295:instrumentation* / Q000379:methods*; D011882:Radiotherapy, High-Energy / Q000592:standards*