Dosimetric Verifications of the Output Factors in the Small Field Less Than 3 cm2 Using the Gafchromic EBT2 Films and the Various Detectors

서지정보

· 발행기관 : 한국의학물리학회
· 수록지 정보 : 의학물리 / 25권 / 4호 / 218 ~ 224페이지
· 저자명 : 오세안, 예지원, 이레나, 박헌보, 김성규

초록

The small field dosimetry is very important in modern radiotherapy because it has been frequently usedto treat the tumor with high dose hypo-fractionated radiotherapy or high dose single fraction stereotacticradiosurgery (SRS) with small size target. But, the dosimetry of a small field (＜3×3 cm2) has been greatchallenges in radiotherapy. Small field dosimetry is difficult because of (a) a lack of lateral electronicequilibrium, (b) steep dose gradients, and (c) partial blocking of the source. The objectives of this studywere to measure and verify with the various detectors the output factors in a small field (＜3 cm) forthe 6 MV photon beams. Output factors were measured using the CC13, CC01, EDGE detector,thermoluminescence dosimeters (TLDs), and Gafchromic EBT2 films at the sizes of field such as0.5×0.5, 1×1, 2×2, 3×3, 5×5, and 10×10 cm2. The differences in the output factors with the variousdetectors increased with decreasing field size. Our study demonstrates that the dosimetry for a smallphoton beam (＜3×3 cm2) should use CC01 or EDGE detectors with a small active volume. And also,Output factors with the EDGE detectors in a small field (＜3×3 cm2) coincided well with the GafchromicEBT2 films.

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