Assessment of dose error due to nylon mesh of treatment couch
| Autor: | Aneela Kanwal, Attia Gul, Mehnaz Liaquat, Nadeem Zia Abbasi, Muhammad Basim Kakakhel, Akbar Ali |
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| Rok vydání: | 2015 |
| Předmět: |
Dose error
business.industry Attenuation Biophysics Radioisotope Teletherapy General Physics and Astronomy Nylon mesh Radiotherapy Dosage General Medicine Radiotherapy Setup Errors Radiation Dosage Imaging phantom Nylons Beam (nautical) Medicine Radiology Nuclear Medicine and imaging Radiation treatment planning Nuclear medicine business Biomedical engineering Skin |
| Zdroj: | Physica medica : PM : an international journal devoted to the applications of physics to medicine and biology : official journal of the Italian Association of Biomedical Physics (AIFB). 31(8) |
| ISSN: | 1724-191X |
| Popis: | Purpose This study aims at the assessment of dose error in patients undergoing radiotherapy due to treatment couch of Co-60 teletherapy unit. Materials and methods In this study beam attenuation due to treatment couch of Co-60 unit was measured in air for different gantry angles and field sizes. Polymethylmethacrylate (PMMA) phantom was used to estimate the effect of depth on attenuation. Impact of couch on surface dose was also evaluated. Results Beam attenuation due to couch was in the range of 0.5–28% for different gantry angles with standard field size of 10 × 10 cm2 with optimum position of metallic cranks. Maximum attenuation (29%) was observed with smallest field size i.e. 5 × 5 cm2. Beam attenuation has been found higher in phantom as compared to that in air However, no particular trend of attenuation has been noted with varying depth of phantom. A 6% increase in surface dose has also been observed due to couch insertion for normal beam incidence. Maximum error of 80% is also note-worthy for most unfavorable situation of irradiation at 180 degree through the metallic cranks. Conclusion It has been determined that ignoring the treatment couch and its accessories can result in dose error of 0.5–80%, depending on gantry angle, field size and position of couch accessories. Therefore, consideration of dose error due to couch during treatment planning is recommended. |
| Databáze: | OpenAIRE |
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