Dynamic range and optimization strategies for radiochromic film calibration using gradient radiation fields.

Autor: Pecic S; Faculty of Physics, University of Belgrade, Belgrade, Serbia., Belca I; Faculty of Physics, University of Belgrade, Belgrade, Serbia., Stojadinovic S; Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas, USA., Nidzovic B; Institute of Oncology and Radiology of Serbia, Belgrade, Serbia., Vicic M; Faculty of Physics, University of Belgrade, Belgrade, Serbia., Devic S; Medical Physics Unit, McGill University, Montreal, Canada.; Department of Radiation Oncology, SMBD Jewish General Hospital, Montreal, Canada.
Jazyk: angličtina
Zdroj: Journal of applied clinical medical physics [J Appl Clin Med Phys] 2024 Oct; Vol. 25 (10), pp. e14481. Date of Electronic Publication: 2024 Aug 12.
DOI: 10.1002/acm2.14481
Abstrakt: This investigation aimed to optimize gradient positioning for radiochromic film calibration to facilitate a uniform distribution of calibration points. The study investigated the influence of various parameters on gradient dose profiles generated by a physical wedge, assessing their impact on the field's dose dynamic range, a scalar quantity representing the span of absorbed doses. Numerical parameterization of the physical wedge profile was used to visualize and quantify the impact of field size, depth, and energy on the dynamic range of dose gradients. This concept enabled the optimization of the gradient positioning and estimation of the necessary number of exposures for the desired calibration dose range. An optimization algorithm based on histogram bin height minimization was developed and presented. The maximum dynamic range was achieved with a 20 × $\times$ 20 cm 2 $\textrm {cm}^{2}$ field size at 5 cm depth. Optimization of wedge gradient positioning yielded the most uniform dose distribution with 7 exposures for the [1,10] Gy range and 8 exposures for the [1,20] Gy range. Film calibration using gradients centered at 1.6, 3, 3.5, and 7 Gy central axis (CAX), obtained through optimized gradient positioning, was showcased. The presented work demonstrates the potential for an improved film calibration process, with efficient material utilization and enhanced dosimetric accuracy for clinical applications. While the method was described for the use of a physical wedge, the methodology can be easily extended to the use of a more convenient dynamic wedge.
(© 2024 The Author(s). Journal of Applied Clinical Medical Physics published by Wiley Periodicals LLC on behalf of American Association of Physicists in Medicine.)
Databáze: MEDLINE
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