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토모다이렉트를 이용한 유방 방사선 조사에서의 Flash 효과 평가

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Alternative Title
Evaluation of the Flash effect in breast irradiation using TomoDirect
Abstract
The breast cancer is cancer that forms in the cells of the breasts, and the
most common cancer in women. The breast cancer treatment options based
on type of breast cancer, its stage and grade, size, and whether the cancer
cells are sensitive to hormones.
Modern radiation therapy has been developed with improvements in the
treatment equipment. TomoTherapy is a recent equipment innovation, and it
can be used to treat multiple targets over the entire body. However, this
approach could be difficult for certain therapy sites, such as lung or breast.
Imaginary contours have been used in such cases in the past, but the
treatment problems for these sites have now been solved with the recent
development of TomoDirect delivery mode. Due to the use of a fixed angle,
TomoDirect can cause a concentrated dose in sites other than the target.
The present study investigated the effect of the PTV contour and the use of
Flash on the dose distribution for breast radiation treatment planning
through the use of a cylindrical phantom.
First, the effect of peripheral delineation in the skin direction of the PTV
was defined by the body contour. The PTV-4 contour, which has a
constant dose distribution below PTV-4, is currently used in the evaluation
of the Flash effect in the tangential region and is associated with breast irradiation using TomoDirect.
Second, the effect of Flash on increasing and decreasing depths inside the
phantom, was investigated. Plans for expanded rectangular PTVs including
the entire Flash area were also designed to compare the Flash effects. The
radiation dose decreased in areas where the depth increased, and the
radiation dose increased when the depth decreased. Constant dose
distribution was observed when the area encompassing Flash was included
in the PTV in the form of an expanded PTV.
Third, the effect of Flash in air, the absolute dose was measured and
compared in plans with PTV contouring. The approach compared several
plans with either the Flash 3 plan or the non-Flash plan. When Flash was
not used, a dose decrease of 12.12% was observed, even with 5 mm of
set-up error. In contrast, when Flash 3 with an air margin of 1.875 cm was
used, accurate dose distribution (with changes within 1% for 15 mm of setup
error) was observed.
According to the investigational study of breast irradiation using
TomoDirect, Flash, which can be applied to obtain the PTV with a relevant
air margin, can reduce the effect of set-up errors in patient positioning.
Author(s)
강대규
Issued Date
2015
Awarded Date
2016. 2
Type
Dissertation
URI
http://dcoll.jejunu.ac.kr/jsp/common/DcLoOrgPer.jsp?sItemId=000000007521
Alternative Author(s)
Kang, Dae-gyu
Department
대학원 의공학협동과정
Advisor
이광만
Table Of Contents
Ⅰ. 서 론 1
1.1 배경 1
1.2 연구 동기 . 1
1.3 연구 목적 . 2
Ⅱ. 유방암의 방사선 치료 3
2.1 유방암 3
2.2 유방암의 치료 방법 3
2.3 유방암의 방사선 치료 . 4
2.3.1 방사선 치료 5
2.3.2 방사선 치료의 종류 5
2.3.3 유방암의 방사선 치료 . 8
Ⅲ. 토모테라피(TomoTherapy) 방사선 치료 장비 10
3.1 헬리컬 시스템(Helical system) 10
3.1.1 기계적 특성 . 11
3.1.2 치료부위 19
3.2 토모다이렉트 시스템(TomoDirect system) 19
3.2.1 기계적 특성 . 20
3.2.2 토모다이렉트를 이용한 유방암 치료. 21
Ⅳ. 토모다이렉트 치료계획 검증 25
4.1 PTV 컨투어에 따른 선량 분포 25
4.2 Flash leaves 개수에 따른 선량분포 28
4.3 Medium 내부에서의 Flash 효과 30
4.4 Flash 에 의한 setup error 의 보정 30
Ⅴ. 결과 및 분석 32
5.1 팬톰 표면과 PTV 컨투어에 따른 치료 계획 결과 변화 . 32
5.2 팬톰과 공기 사이의 영역에서 Flash leaf 의 개수가 선량 분포에 미치는 영향. 36
5.3 팬톰 내부에서의 Flash 효과 38
5.4 Setup error 발생에 대한 Flash 효과 41
Ⅵ. 결론 43
6.1 토의 . 43
6.2 추후연구 45
6.3 결어 . 45
참 고 문 헌 47
Degree
Doctor
Publisher
제주대학교 대학원
Citation
강대규. (2015). 토모다이렉트를 이용한 유방 방사선 조사에서의 Flash 효과 평가
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Interdisciplinary Programs > Interdisciplinary Postgraduate Program in Biomedical Engineering
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