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Energy constancy checking for electron beams using a wedge‐shaped solid phantom combined with a beam profile scanner
Author(s) -
Rosenow Ulf F.,
Islam Mohammad K.,
Gaballa Hani,
Rashid Harunor
Publication year - 1991
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.596719
Subject(s) - imaging phantom , scanner , flatness (cosmology) , optics , ionization chamber , wedge (geometry) , reproducibility , beam (structure) , photon , cathode ray , physics , electron , ionization , materials science , mathematics , nuclear physics , ion , statistics , cosmology , quantum mechanics
An energy constancy checking method is presented which involves a specially designed wedge‐shaped solid phantom in combination with a multiple channel ionization chamber array known as the Thebes device. Once the phantom/beam scanner combination is set up, measurements for all electron energies can be made and evaluated without re‐entering the treatment room. This is also valid for the readjustment of beam energies which are found to deviate from required settings. The immediate presentation of the measurements is in the form of crossplots which resemble depth dose profiles. The evaluation of the measured data can be performed using a hand‐held calculator, but processing of the measured signals through a PC‐type computer is advisable. The method is insensitive to usual fluctuations in beam flatness. The sensitivity and reproducibility of the method are more than adequate. The method may also be used in modified form for photon beams.