J Korean Soc Ther Radiol.
1995 Dec;13(4):397-402.
The Study of Tissue Dose Perturbation by Air Cavity with 6MV Photon Beam
- Affiliations
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- 1Department of Therapeutic Radiology, Medical College, Kosin University, Pusan, Korea.
Abstract
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PURPOSE: To determine the perturbation effect in the tissue downstream from surface layers of lesions located in the air/tumor-tissue interface of larynx using 6MV photon beam.
MATERIALS AND METHODS
Thermoluminescent dosimeters(TLDs). Were embedded at 3 measurement locations in slab no.7 of a humanoid phantom and exposed to forward and backward direction using various field sizes(4X4cm2 - 15X15 cm2).
RESULTS
At the air/tissue interface, forward dose perturbation factor(FDPF) is about 1.085 with 4X4 cm2, 1.05 with 7X7 cm2, 1.048 with 10X10cm2, and 1.041 with 15X15cm2. Backscatter dose perturbation factor(BDPF) is about 0.99 with 4X4cm2, 0.981 with 7X7cm2, 0.956 with 10X10cm2 and 0.97 with 15X15cm2 .
CONCLUSION
FDPF is greater as field size is smaller. And FDPF is smaller as the distance is further from the air/tissue interface.