Study of the penumbra for high-energy photon beams with Gafchromic (TM) EBT2 films

Title
Study of the penumbra for high-energy photon beams with Gafchromic (TM) EBT2 films
Author(s)
김성규오세안[오세안]강민규예지원오영기[오영기]
Keywords
RADIOCHROMIC FILM; DOSIMETRY
Issue Date
201206
Publisher
KOREAN PHYSICAL SOC
Citation
JOURNAL OF THE KOREAN PHYSICAL SOCIETY, v.60, no.11, pp.1973 - 1976
Abstract
The penumbra has a major impact on obtaining uniformity of isodose distributions in radiation therapy. The penumbra phenomena of intensity-modulated radiation therapy (IMRT) techniques using multi-leaf collimators (MLCs) has an impact on the dose distributions in the border of the target volumes and the MLC. The aim of this study was to determine the impact of high photon energy (6 MV, 10 MV) on the penumbra for various depths and field sizes by using the Pencil Beam Convolution algorithms (eclipse 8.6) and self-developing Gafchromic (TM) EBT2 film. For dose calculations and EBT2 measurements, we used an acryl phantom with dimensions 20 x 20 x 20 cm(3). The 200 cGy dose was delivered to the central depth (10 cm) of the acryl phantom. The result of this study was that increased energy, field size and depth are rise to an increased penumbra (20% similar to 80%) width. For a 6 MV photon energy, the penumbra widths (20%-80%) at 1.5 cm, 5 cm, and 10 cm depths were 4.2 mm, 4.4 mm, and 5.7 mm for the eclipse calculations and 2.9 mm, 4.1 mm, and 4.2 mm for the EBT2 film measurements for 10 x 10 cm(2) field sizes, respectively. For a 10 MV photon energy, the penumbra widths were 4.5 mm, 4.7 mm, and 6.2 mm for eclipse calculations and 4.1 mm, 4.6 mm, and 4.9 mm for EBT2 film measurements, respectively. As the field size was changed to 3 cm, 5 cm, 7 cm, 10 cm, and 15 cm, the penumbra widths changed to 5.1 mm, 5.3 mm, 5.6 mm, 5.9 mm, and 6.1 mm for eclipse calculations and 2.9 mm, 3.3 mm, 3.6 mm, 4.2 mm, and 5.1 mm for EBT2 measurements, respectively, for 10 cm depths for 6 MV photon energies. In this study, compared to the 10 MV photon energy, the 6 MV photon energy was preferred in treatments such as the 3D conformal radiation therapy and the IMRT for critical organs near the target volume.
URI
http://hdl.handle.net/YU.REPOSITORY/28134http://dx.doi.org/10.3938/jkps.60.1973
ISSN
0374-4884
Appears in Collections:
의과대학 > 방사선종양학교실 > Articles
Files in This Item:
There are no files associated with this item.
Export
RIS (EndNote)
XLS (Excel)
XML


qrcode

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.

BROWSE