Dependence of tissue inhomogeneity correction factors on photon-beam energy

• Autorzy: Akhtaruzzaman M. , Kukolowicz P.

Identyfikatory

DOI

10.1515/nuka-2018-0001

• Języki publikacji: EN

Abstrakty

EN

Introduction: Commissioning of the treatment-planning system includes the accuracy of dose calculations in the inhomogeneous absorber. Several results of measurements with regard to inhomogeneity correction factors (CFs) have been published. However, the dependence of CFs on photon-beam energy may preclude such results from being applied to the photon beams of general users. Purpose: The aim of this study was to assess the dependence of CFs on the photon-beam energy. Materials and methods: CFs were calculated by the Batho method for several slab geometries comprised of concentrations of lung tissue and water of 0.25 and 1.00 g/cm3, respectively. The CFs were calculated at 6 MV (TPR10 = 0.67 ± k * 0.01) and 15 MV (TPR10 = 0.76 ± k * 0.01) where k = –3, –2, –1, 0, 1, 2, 3. All calculations were performed in the region where a charged-particle equilibrium exists. Results: Changes in CFs of less than 2% were observed across the considered energy ranges. With a change in TPR20,10 of 0.01, both at 6 and 15 MV at a depth of 5 cm below the lung; and lung thicknesses of 3, 5 and 8 cm over a fi eld surface area of 10 × 10 cm2, the change in CF never exceeded 2.4%. The dependences of changes in CFs in terms of TPR20,10 were 1.74% and 1.20% for fi eld surface areas of 5 × 5 cm2 and 20 × 20 cm2, respectively. A comparison of 42 linear accelerators (LINACs) exhibiting 6 MV and 15 MV of energy installed in Poland showed that the maximum differences in terms of TPR20,10 at 6 MV and 15 MV were 4.2% and 2.2%, respectively. Conclusion: A linear dependence of CFs on energy was observed. According to observations, the smaller the surface area of the fi eld and deeper the point of interest below the lung, the more dependent CFs are on energy.

Słowa kluczowe

EN

Batho method; dose calculation; inhomogeneity correction factors; photon-beam energy

• Wydawca: Institute of Nuclear Chemistry and Technology
• Czasopismo: Nukleonika
• Rocznik: 2018
• Tom: Vol. 63, No. 1
• Strony: 3--7
• Opis fizyczny: Bibliogr. 33 poz., rys.

Twórcy

autor

Akhtaruzzaman M.

• Faculty of Physics University of Warsaw Ludwika Pasteura 5, 02-093 Warsaw, Poland
• Department of Medical Physics Maria Skłodowska-Curie Memorial Cancer Centre and Institute of Oncology Roentgena 5, 02-781 Warsaw, Poland

autor

Kukolowicz P.

• Department of Medical Physics Maria Skłodowska-Curie Memorial Cancer Centre and Institute of Oncology Roentgena 5, 02-781 Warsaw, Poland

Bibliografia

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Uwagi

PL

Opracowanie w ramach umowy 509/P-DUN/2018 ze środków MNiSW przeznaczonych na działalność upowszechniającą naukę (2018).