J Korean Soc Ther Radiol.
1983 Mar;1(1):25-28.
A Study on the Use of 10 MV X-ay with Lead Absorber for Treatment of Hean and Neck Tumors
- Affiliations
-
- 1Department of Radiology, College of Medicine, Seoul National University, Korea.
Abstract
-
Anterior and posterior parallel opposed field technique covering entire neck is desirable for elimination of junctional problems in treating upper neck with bilateral parallel opposed fields and lower neck with anterior one field. For good dose distribution in neck, dose in build-p region should be high for anterior field and should be low for posterior field. And so, with 10 MV X-ay, lead absorber was used for anterior field only. The adequate thickness of lead absorber, absorber-kin separation, width of central cord block for posterior field and anterior & posterior field weight were studied using film dosimery. The results are as follows. 1. As the thickness of the lead absorber increased the dose in build-p region increased. 2. As the absorber-kin separation decreased the dose in build-p region increased. 3. The adequate thickness of lead absorber was around 5.6mm. 4. The adequate absorber-kin separation was around 5cm. 5. The adequate posterior cord block width was 3cm. 6. 4:1 weighting for anterior and posterior field was adequate. And so with this technique, adequate dose distribution could be made as well as elimination junction problems.