Ядерна фізика та енергетика Nuclear Physics and Atomic Energy   ISSN: 1818-331X (Print), 2074-0565 (Online)   Publisher: Institute for Nuclear Research of the National Academy of Sciences of Ukraine   Languages: Ukrainian, English   Periodicity: 4 times per year   Open access peer reviewed journal

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K. Vilchynska^1,2, O. Bezshyyko¹, L. Golinka-Bezshyyko^1,*, R. Zelinskyi<sup>3

1</sup> Taras Shevchenko National University of Kyiv, Kyiv, Ukraine
² Radiotherapy Department, Universal Clinic "Oberig", Kyiv, Ukraine
³ Radiotherapy Department, Medical Center of Yuriy Spizhenko LLC, Kyiv, Ukraine

^*Corresponding author. E-mail address: lyalkagb@gmail.com

Abstract: The study investigates the dose distributions in large (10 cm × 10 cm) and small (1 cm × 1 cm) radiation fields, comparing calculated and measured data using two detectors. Special attention is given to the impact of source occlusion in small fields and the phenomenon of penumbra overlap, as predicted by theoretical models. Small radiation fields, crucial in clinical radiation therapy, present unique challenges in dosimetry due to these effects. The results highlight the discrepancies between large and small fields, emphasizing the importance of precise measurement and the limitations of current dosimetric equipment in small-field applications.

Keywords: radiation therapy, quality assurance, detectors, radiochromic film, linear accelerator, treatment planning system, dose distribution.

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