Reliability of clinical port films for measuring dose inhomogeneities in radiotherapy for head and neck tumours.
Reproducibility and reliability of film dosimetry are evaluated in clinical circumstances. Optical densities were read on 82 routinely taken verification films of Ear-Nose-Throat (ENT) treatment fields and corrected with the sensitometric curve to obtain relative dose values. Off-axis ratios measured on 10 successive films of one specific field were compared with each other and show a good reproducibility (s = 1.7%). Reliability was assessed by comparing 82 off-axis ratios obtained on the films with off-axis ratios obtained by simultaneously performed diode measurements. Only small relative differences were detected (mean = 1.1%, s = 3.0).
Weltens
C
C
Department of Radiotherapy, University Hospital Sint Rafael, University of Leuven, Belgium.
van Dam
J
J
Leunens
G
G
Dutreix
A
A
van der Schueren
E
E
D005373:Film Dosimetry / Q000592:standards*; D006258:Head and Neck Neoplasms / Q000532:radiotherapy*; D006801:Humans; D011882:Radiotherapy, High-Energy; D015203:Reproducibility of Results