A Study on Rebuildup of 6MV X-ray by the Cavity.
- Author:
Moon June CHO
1
;
Eun Kyung CHOI
;
Woong Ki CHUNG
;
Wee Saing KANG
;
Charn Il PARK
Author Information
1. Department of Therapeutic Radiology, College off Medicine, Seoul National University, Seoul, Korea.
- Publication Type:Original Article
- Keywords:
Rebuildup;
Air cavity;
5 MV X-ray
- MeSH:
Skin
- From:Journal of the Korean Society for Therapeutic Radiology
1989;7(1):113-122
- CountryRepublic of Korea
- Language:Korean
-
Abstract:
The inclusion of air filled cavities in treatment fields creates a potential dosimetric problem due to the rebuildup phenomenon near the air-tissue interface using a simulated phantom, such as air gap, air cylinder, and air cavity, the amount of rebuldup along the various field sizes and air cavity dimensions was measured. The results are as follows. 1. As the field size becomes larger in comparison with the cavity size, or as the cavity size gets bigger when the field size is equal to the cavity size, rebuildup decreases. 2. When the distance between the phantom surface and the air cavity is less than 1.5 cm, there is prominent rebuildup. And when the distance is more than 1.5 cm, rebuildup is relatively constant. 3. The change according to the depth of the cavity is affected by the field size and the cavity size, rebuildup usually increases when the depth of the cavity increases. 4. It is suggested that tissue equivalent material should be applied on the skin to make tissue thickness over the air cavity more than 1.5 cm and that the field size should include the air cavity with at least 1 cm margin.
