The influence of the bolus-surface distance on the dose distribution in the build-up region
| Autor: | Jakub Reguła, Martyna Sroka, Włodzimierz Łobodziec |
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| Rok vydání: | 2010 |
| Předmět: |
Cancer Research
Materials science PDD Quantitative Biology::Tissues and Organs Physics::Medical Physics Dose distribution Depth of the dose maximum Computational physics Bolus Surface distance Oncology Radiology Nuclear Medicine and imaging Build-up region Radiology Nuclear Medicine and imaging Original Article Bolus (radiation therapy) Biomedical engineering |
| Zdroj: | Reports of practical oncology and radiotherapy : journal of Greatpoland Cancer Center in Poznan and Polish Society of Radiation Oncology. 15(6) |
| ISSN: | 1507-1367 |
| Popis: | AimThe aim of the paper is to examine the relation between the increase of the photon dose in water in the region of electronic disequilibrium – so-called build-up region – and the distance of the bolus from the water surface for the applied parameters of X-ray beams.Materials and methodsPDD measurements were carried out using the plane-parallel ionization chamber Markus in the automatic water phantom IBA BluePhantom with OmniPro-Accept V7 (IBA Dosimetry GmbH, Schwarzenbruck, Germany). All measurements were performed for different field sizes and for 6MV and 15MV X-ray beams, respectively. A water-equivalent RW3 slab (Goettingen White Water) produced by PTW was used as a bolus.ResultsPlacing a bolus in an irradiated field changes the shape of the PDD curve in the build-up region in comparison with the one obtained for an open field. All results has been inserted in tables and figures.ConclusionThe closer the bolus is to the water surface, the smaller the depth of the maximum dose in the phantom for all investigated fields and energies. The changes in the build-up region are important, even if the bolus does not touch the surface of the water phantom. The influence of the bolus can be ignored when the bolus-surface distance equals 25cm for 6MV X-ray beams and 39cm for 15MV X-ray beams. |
| Databáze: | OpenAIRE |
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