Publications by authors named "S M Vatnitsky"
. To review the currently available data on beam quality correction factors,kQ,for ionization chambers in clinical proton beams and derive their current best estimates for the updated recommendations of the IAEA TRS-398 Code of Practice..
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- An independent dosimetry audit for proton therapy delivery is recommended to ensure consistent treatments across different centers; this study outlines a methodology developed through collaboration between MedAustron and the National Physical Laboratory.
- The auditing process involved using phantoms—one homogeneous and one anthropomorphic—dosed with ionization chambers, alanine pellets, and radiochromic films to evaluate treatment accuracy under different scenarios.
- Results showed that measurements using alanine pellets and ionization chambers were consistent, with minimal deviations from predicted doses; the successful application of this audit method at five proton centers suggests it could be valuable for future clinical trial credentialing in proton beam therapy.
Purpose: The local depth dose gradient and the displacement correction factor for Farmer-type ionization chambers are quantified for reference dosimetry at shallow depth in single-layer scanned proton fields.
Method: Integrated radial profiles as a function of depth (IRPDs) measured at three proton therapy centers were smoothed by polynomial fits. The local relative depth dose gradient at measurement depths from 1 to 5 cm were derived from the derivatives of those fits.
Purpose: This paper presents the implementation and comparison of two independent methods of beam monitor calibration in terms of number of particles for scanned proton and carbon ion beams.
Methods: In the first method, called the single-layer method, dose-area-product to water (DAP) is derived from the absorbed dose to water determined using a Roos-type plane-parallel ionization chamber in single-energy scanned beams. This is considered the reference method for the beam monitor calibration in the clinically relevant proton and carbon energy ranges.
The IAEA is currently coordinating a multi-year project to update the TRS-398 Code of Practice for the dosimetry of external beam radiotherapy based on standards of absorbed dose to water. One major aspect of the project is the determination of new beam quality correction factors, k , for megavoltage photon beams consistent with developments in radiotherapy dosimetry and technology since the publication of TRS-398 in 2000. Specifically, all values must be based on, or consistent with, the key data of ICRU Report 90.
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