Open AccessRadiotherapy dose calculation on KV cone‐beam CT image for lung tumor using the CIRS calibration
Author(s) -
Ma Changsheng,
Cao Jianping,
Yin Yong,
Zhu Jian
Publication year - 2014
Publication title -
thoracic cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.823
H-Index - 28
eISSN - 1759-7714
pISSN - 1759-7706
DOI - 10.1111/1759-7714.12055
Subject(s) - hounsfield scale , medicine , cone beam computed tomography , imaging phantom , nuclear medicine , cone beam ct , calibration , image guided radiation therapy , radiation therapy , computed tomography , radiology , physics , quantum mechanics
On‐board kilovoltage ( KV ) cone‐beam computed tomography ( CBCT ) images are used predominantly for the setup of patients' positioning. The image data can also potentially be used for dose calculation with the precise calibration of H ounsfield units ( HU ) to electron density ( HU ‐density). CBCT calibration was analyzed in this study. A clinical treatment planning system was employed for CT and KV CBCT image to dose calculations and subsequent comparisons. Two HU ‐density tables were generated using the C omputerized I maging R eference S ystems ( CIRS ) phantom. The results showed that a maximum ∼4% dose discrepancy was observed for inserts. The single field isodose curves were very close. The lung clinical patient study indicated that the volume of lung tumor that achieved the prescribed dose in CBCT was lower than in the CT plan. Our study showed that the dosimetric accuracy of CBCT ‐based dose calculation for lung tumor is acceptable only for the purpose of dosimetric checks with calibration applied. KV CBCT images cannot replace traditional CT images for dose calculation accuracy.