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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-22 1:57 |
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Conference: Bucharest University Faculty of Physics 2024 Meeting
Section: Biophysics; Medical Physics
Title:
Photon Beam Attenuation in Radiotherapy: The Influence of Treatment Couches
Authors:
Marius-Valentin COSTACHE, Madalina CROITORIU
Affiliation:
MNT HealthCare Europe SRL, Neolife Baneasa, Bulveradul Ficusului 40, Bucuresti, Romania
E-mail
cm.valentin299@gmail.com
Keywords:
Beam Attenuation, Dose Calculation, Ionization Chamber, SRS MapCheck Detector, Point Dose Evaluation, Gamma Analysis
Abstract:
This study investigates the impact of treatment couches on the attenuation of a clinical photon beam in radiotherapy, specifically utilizing the TrueBeam STX linear accelerator with HD120 multi-leaf collimator. Accurate dose delivery is crucial in radiotherapy, and any attenuation caused by objects in the beam path, such as the treatment couch, can alter the treatment efficacy. Point dose evaluation was conducted by performing multiple plans with and without the couch using multiple dose calculation algorithms (e.g. Analytical Anisotropic Algorithm and Acuros AXB), utilizing the Exradin MicroPoint Ionization Chamber placed inside water equivalent blocks fitted inside a StereoPhan holder of a SRS MapCheck detector from Sun Nuclear Corporation. Clinical SBRT cases (high dose treatments inside a small volume), are also investigated using Gamma Analysis with criteria as low as 2% dose difference and 1% distance to agreement. Results show a difference of up to 3% absorbed dose for an overall treatment fractionation, which highlights the necessity of accounting for couch-induced attenuation by inserting the couch model inside the dose calculation. This practice enhances the dose accuracy and overall therapeutic effectiveness of a treatment plan for patients undergoing radiotherapy.
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