의료용 선형가속기의 소조사면에 대한 검출기 종류에 따른 평
Evaluation of the Small Field of for the Detector Type Medical Linear Accelerator
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초록
최근 선형가속기를 이용한 방사선치료는 세기조절방사선치료, 정위적방사선치료 등이 널리 사용되고 있다. 이러 한 방사선 치료기법은 일반적으로 역방향치료계획을 사용함으로써 소조사면을 제외하기 어렵다. 그러므로 소조사 면의 선량특성에 관한 정확한 측정이 필요하다. 따라서 유효체적이 서로 다른 검출기를 이용하여 소조사면에 대한 깊이선량백분율, 빔측면도, 그리고 선량출력계수를 측정하여 각 검출기의 선량특성 평가하고자 하였다. 실험 결과 X-선 6 MV에너지에 대한 빔선질(PDD20/PDD10)은 10 × 10 cm2에서 Diode 검출기는 Pinpoint 검출 기에 비해 2.4%로 높았다. 모든 조사면에서 유효체적이 작은 Diode 검출기가 다른 검출기들과 50%이상 작은 반 음영을 보여 공간분해능이 우수한 것으로 평가되었다. 출력선량계수는 조사면 2 × 2 cm2에서 Semiflex 검출기 다 른 검출기에 비해 2%정도 적게 측정되기 시작해서 조사면 1 × 1 cm2에서는 20%정도 차이를 이며 유효성이 없는 것으로 판단된다. 조사면 1 × 1 cm2에서 Diode 검출기와 Pinpoint 검출기의 측정값은 13%정도 차이를 보였다. 조 사면 3 × 3 cm2이하에서는 검출기의 유효체적에 따른 출력선량계수의 차이가 크므로 가능한 유효체적이 작은 검 출기를 사용해야 될 것으로 사료된다.
Abstract
Recently linear accelerator of radiation therapy intensity modulated radiation therapy, stereotactic radiation therapy are widely used. Such radiation treatment techniques are generally difficult to exclude the small field by using the inverse treatment plan. It is necessary to dose an accurate measurement of characteristics of the small field. Thus, using different detectors to measure the volume of the effective percentage depth dose, beam profile, and the output factor of the small field was to evaluate the dose characteristics of each detector. Experimental results for the X-ray beam 6 MV energy beam quality(PDD20/PDD10) is 10 × 10 cm2 Diode detector is as high as 2.4% compared to Pinpoint detector. All field size to lesser effective volume of Diode detector shows that it is far better than other detectors by more than 50% of small penumbra, therefore spatial resolution far excellent. In field size 2 × 2 cm2 Semiflex detector was measured about 2% less than the other detector. Field size 1 × 1 cm2 is that there is no judgment about the validity show the difference between 20%. Field size 1 × 1 cm2 from the measured values of the Diode detector and Pinpoint detector showed a 13% difference. Less than field size 3 × 3 cm2 the feed to the difference between the output factor of the effective volume of the detector to be used for the effective volume available to the detector.
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