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A quality assurance method for analyzing and verifying intensity modulated fields
Author(s) -
Ma Lijun,
Phaisangittisakul N.,
Yu C. X.,
Sarfaraz M.
Publication year - 2003
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 - 10.1118/1.1592896
Subject(s) - quality assurance , dosimetry , intensity modulation , beam (structure) , intensity (physics) , confidence interval , nuclear medicine , kernel (algebra) , optics , medicine , mathematics , physics , statistics , external quality assessment , pathology , combinatorics , phase modulation , phase noise
A quality assurance method is developed for measuring, verifying and analyzing intensity modulated radiation fields. It is applicable for rotational and fixed‐beam intensity modulated radiation therapy (IMRT) treatments. A gantry‐mount device was constructed to measure the transmission dose of an IMRT field using radiographic films. A double‐exposure technique with optimal kernel estimate method was developed to minimize the errors from measurements. A χ 2confidence level test method was developed to detect the discrepancies between measured and prescribed IMRT fluence distributions. Our method was tested for rotational and fixed‐beam IMRT treatment verifications. The method was found insensitive to the hardware‐related parameters for rotational and fixed‐beam IMRT deliveries. The χ 2confidence level test was found to be more sensitive than linear correlation method in detecting relative small errors for cases with a few segments or narrow regions of interest. In conclusion, we demonstrated a quantitative method for verifying and analyzing IMRT treatment deliveries.