{"title":"Film measurements of kilovoltage x-ray percentage depth doses for different energies and field sizes.","authors":"Tze Yee Lim, Dershan Luo, Jamshid Moradi Kurdestany, Xin Wang, Ramesh Tailor","doi":"10.1093/bjr/tqaf107","DOIUrl":null,"url":null,"abstract":"<p><strong>Objectives: </strong>Kilovoltage x-ray therapy, which includes superficial x-rays and orthovoltage x-rays, is particularly suited for treatments near the skin surface. Radiation dose deposition at depth is typically characterized by percentage depth dose (PDD) curves. However, PDD data are difficult to obtain in kilovoltage x-ray therapy, hence clinics often rely on British Journal of Radiology Supplement 25 (BJR-25) archival data. This study measured PDD for different energies and field sizes on the Xstrahl 300 kilovoltage x-ray therapy unit for comparison with BJR-25 data.</p><p><strong>Methods: </strong>We irradiated EBT3 film in water using different energy and field size combinations, then compared the acquired PDD curves with BJR-25 data. We used 75 kVp, 125 kVp, and 250 kVp beams, for 10 × 10 cm2 open field, 4 × 4 cm2 closed-ended square applicator, and open-ended circular applicators of 1.5 cm, 2.0 cm, 2.8 cm, and 4.7 cm diameter.</p><p><strong>Results: </strong>PDD for different energies and field sizes on the Xstrahl 300 kilovoltage x-ray therapy unit agreed well with BJR-25 data. The average difference between measured and BJR-25 data was -0.3 ± 1.8%; 85.9% of the individual local differences were within ±3%, 94.8% within ±4%, and 99.5% within ±5%.</p><p><strong>Conclusions: </strong>The PDD curves presented here, together with BJR-25 data, can serve as useful comparison datasets for the commissioning of kilovoltage x-ray machines.</p><p><strong>Advances in knowledge: </strong>Our film-based measurement technique provides high spatial resolution PDD datapoints for a modern kilovoltage x-ray unit, adding to the limited published data in the kilovoltage energy range.</p>","PeriodicalId":9306,"journal":{"name":"British Journal of Radiology","volume":" ","pages":""},"PeriodicalIF":1.8000,"publicationDate":"2025-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"British Journal of Radiology","FirstCategoryId":"3","ListUrlMain":"https://doi.org/10.1093/bjr/tqaf107","RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"RADIOLOGY, NUCLEAR MEDICINE & MEDICAL IMAGING","Score":null,"Total":0}
引用次数: 0
Abstract
Objectives: Kilovoltage x-ray therapy, which includes superficial x-rays and orthovoltage x-rays, is particularly suited for treatments near the skin surface. Radiation dose deposition at depth is typically characterized by percentage depth dose (PDD) curves. However, PDD data are difficult to obtain in kilovoltage x-ray therapy, hence clinics often rely on British Journal of Radiology Supplement 25 (BJR-25) archival data. This study measured PDD for different energies and field sizes on the Xstrahl 300 kilovoltage x-ray therapy unit for comparison with BJR-25 data.
Methods: We irradiated EBT3 film in water using different energy and field size combinations, then compared the acquired PDD curves with BJR-25 data. We used 75 kVp, 125 kVp, and 250 kVp beams, for 10 × 10 cm2 open field, 4 × 4 cm2 closed-ended square applicator, and open-ended circular applicators of 1.5 cm, 2.0 cm, 2.8 cm, and 4.7 cm diameter.
Results: PDD for different energies and field sizes on the Xstrahl 300 kilovoltage x-ray therapy unit agreed well with BJR-25 data. The average difference between measured and BJR-25 data was -0.3 ± 1.8%; 85.9% of the individual local differences were within ±3%, 94.8% within ±4%, and 99.5% within ±5%.
Conclusions: The PDD curves presented here, together with BJR-25 data, can serve as useful comparison datasets for the commissioning of kilovoltage x-ray machines.
Advances in knowledge: Our film-based measurement technique provides high spatial resolution PDD datapoints for a modern kilovoltage x-ray unit, adding to the limited published data in the kilovoltage energy range.
期刊介绍:
BJR is the international research journal of the British Institute of Radiology and is the oldest scientific journal in the field of radiology and related sciences.
Dating back to 1896, BJR’s history is radiology’s history, and the journal has featured some landmark papers such as the first description of Computed Tomography "Computerized transverse axial tomography" by Godfrey Hounsfield in 1973. A valuable historical resource, the complete BJR archive has been digitized from 1896.
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