RECOMMENDATION FOR DEPTH MEASUREMENT OF WEDGE TRANSMISSION FACTORS FOR HIGH ENERGY PHOTON BEAMS

Authors

  • C. KAKANAPORN Department of Radiology, Faculty of Medicine, Siriraj Hospital, Mahidol University
  • N. MANATRAKUL Division of Radiation Oncology, National Cancer Institute
  • P. SOPHONPIS Department of Radiological Technology, Faculty of Medical Technology, Mahidol University
  • P. PROMYART Department of Radiological Technology, Faculty of Medical Technology, Mahidol University

Abstract

In clinical practice, it is often assumed that wedge transmission factor (WTF) is independent of depth. Measurements have been experimented which demonstrated a clinically significant variation in WTF, as much as 6.8% for A 60° wedge between 5 and 15 cm. depth. The measurements were performed for various field sizes at depth of maximum dose (dmax), 5, 10 and 15 cm. depths. It made with ionization chamber in solid phantom with 80 cm. SSD for Co-60, and 100 cm. SSD for three linear accelera- tor x-ray beams with energies of 6, 10 and 15 MV. From our experiments, these system- atic measurements on WTF show that in general there is a definite dependence at vari- ous depths varies with beam energy and wedge angle. And the recommended depth of measurement should be 5 cm depth for Co-60 gamma ray, 6 and 10 MV x-rays, and 5 cm or 10 cm depth for 15 MV x-rays.

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References

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Published

2023-04-08

How to Cite

1.
KAKANAPORN C, MANATRAKUL N, SOPHONPIS P, PROMYART P. RECOMMENDATION FOR DEPTH MEASUREMENT OF WEDGE TRANSMISSION FACTORS FOR HIGH ENERGY PHOTON BEAMS. ASEAN J Radiol [Internet]. 2023 Apr. 8 [cited 2024 Jul. 4];4(2):201-5. Available from: https://asean-journal-radiology.org/index.php/ajr/article/view/443

Issue

Vol. 4 No. 2 (1998): May - August

Section

Original Article

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