Photon Contamination Analysis (Bremsstrahlung tail) of Electron Beams in Small Fields

Authors

  • Sadip Barua Department of Physics, University of Chittagong, Chattogram, Bangladesh.
  • M A Hasnat Institute of Nuclear Medical Physics (INMP), AERE, Savar.
  • Samiul Alim Institute of Nuclear Medical Physics (INMP), AERE, Savar.
  • Fatema Tuz Zohra Institute of Nuclear Medical Physics (INMP), AERE, Savar.
  • Priyanka Poddar Institute of Nuclear Medical Physics (INMP), AERE, Savar.
  • M Rafiqul Islam Institute of Nuclear Medical Physics (INMP), AERE, Savar.
  • S C B Sarma National Institute of Nuclear Medicine and Allied Sciences.
  • Santunu Purohit Department of Physics, University of Chittagong, Chattogram, Bangladesh.
  • Mohammad Nasirul Hoque Department of Physics, University of Chittagong, Chattogram, Bangladesh.
  • M M Ahasan Institute of Nuclear Medical Physics (INMP), AERE, Savar.

DOI:

https://doi.org/10.3329/bjnm.v28i1.79545

Keywords:

Radiotherapy, Bremsstrahlung tail, Percentage of depth dosage, Electron Beam

Abstract

Intensity-modulated radiotherapy, volumetric arc radiotherapy, and stereotactic radiosurgery are three modern radiotherapy applications that commonly use dosimetry of small fields. Field sizes ranging from 1 × 1 cm² to 5 × 5 cm² are taken for analysis. Varian Clinac IX SN6298 was utilized for both 6 and 12 MeV electron beams, using the TRS-398 and IAEA Technical Reports Series No. 483 procedure as the standard. The beam profile and the percentage of depth dosage (PDD) were finally ascertained in a water phantom. Various percent dosages and Bremsstrahlung tail regions were experimentally measured from the PDD curves. With an increase in field size (s), R100, R90, R80, R50, and Rp all rose for the medical linear accelerators. In the CC13 chamber, this held true for both 6 MeV and 12 MeV electron beams. The area of the bremsstrahlung tail grows as energy increases. This may result in modifications to the penumbra region's dosage distribution. Beam profiles revealed that dose was scattered more in small fields than in intermediate sizes. The interactions between the radiation beam, detector, and surrounding materials make small-field dosimetry difficult. Additionally, none of the beam symmetries exceed 2%.

Bangladesh J. Nuclear Med. 28(1): 135-141, 2025

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Published

2025-04-13

How to Cite

Barua, S., Hasnat, M. A., Alim, S., Zohra, F. T., Poddar, P., Islam, M. R., … Ahasan, M. M. (2025). Photon Contamination Analysis (Bremsstrahlung tail) of Electron Beams in Small Fields. Bangladesh Journal of Nuclear Medicine, 28(1), 135–141. https://doi.org/10.3329/bjnm.v28i1.79545

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Original Articles