Dosimetric Characteristics on Penumbra Regions of the multileaf Collimator as Compared with the Lead Alloy Block.
- Author:
Sang Wook LEE
1
;
Young Tack OH
;
Woo Cheol KIM
;
Ki Chang KEUM
;
Seong Ick YOON
;
Hyun Soo KIM
;
Won PARK
;
Seong Sil CHU
;
Gwi Eon KIM
Author Information
1. Department of Radiation Oncology, Yonsei University College of Medicine, Seoul, Korea.
- Publication Type:Original Article
- Keywords:
Multileaf collimator;
Effective penumbra;
Film dosimetry
- MeSH:
Alloys*;
Film Dosimetry;
Pectinidae;
Radiotherapy, Conformal
- From:Journal of the Korean Society for Therapeutic Radiology
1995;13(4):391-396
- CountryRepublic of Korea
- Language:Korean
-
Abstract:
PURPOSE: The Conformal Radiation Therapy has been widely used under favour of development of computer technologies. The delivery of a large number of static radiation fields are being necessary for the conformal irradiation. In this paper, we investigate dosimetric characteristics on penumbra regions of a multileaf collimator(MLC), and compare to those of lead alloy block for he optimal use of the system in 3-D conformal radiotherapy. MATERIALS AND METHODS: The measurement of penumbra by MLC or lead alloy block was performed with 6 or 10 MV X-rays. The film was positioned at a dmax depth and 10 cm depth, and its optical density was determined using a scanning videodensitometer. The effective penumbra, the distance from 80% to 20% isodose lines and 90 to 10 were analyzed as a function of the angle between the direction of leaf motion and the edge defined by leaves. RESULTS: Increasing MLC angle (0-75degree) was observed with increasing the penumbra widths and the scalloping effect. There was no definite differences of penumbra width from 80% to 20% isodose lines, while being the small increase of penumbra width of lead alloy block are agree reasonably with those of MLC within 4.8mm. CONCLUSION: The comparative qualitative study of the penumbra between MLC and lead alloy block demonstrate the clinical acceptability and suitability of the multileaf collimator for 3-D conformal radiotherapy.
