DOSIMETRIC ANALYSIS OF PHOTON BEAMS IN MEDICAL IMAGING AND RADIOTHERAPY

Abstract

Dosimetric analysis of photon beams is a critical component in both medical imaging and radiotherapy, as it ensures accurate dose delivery while minimizing unnecessary radiation exposure to patients. Photon beams interact with biological tissues through complex physical mechanisms, resulting in energy deposition that directly influences image quality and therapeutic effectiveness. Precise dosimetric evaluation is therefore essential for optimizing diagnostic procedures, improving treatment outcomes, and enhancing patient safety.

In medical imaging, particularly in X-ray radiography and computed tomography, dosimetry plays a vital role in balancing image quality against radiation dose. Excessive exposure may increase the risk of stochastic effects, whereas insufficient dose can degrade diagnostic accuracy. In radiotherapy, high-energy photon beams are employed to deliver lethal doses to malignant tissues while sparing surrounding healthy organs. This requires accurate dose calculation, beam modeling, and verification techniques to account for photon attenuation, scattering, and secondary particle production.

This article presents a comprehensive analysis of photon beam dosimetry in medical imaging and radiotherapy. Key dosimetric quantities, including absorbed dose, air kerma, dose equivalent, and energy fluence, are discussed in relation to photon–matter interaction processes. Modern dosimetric methods, such as ionization chambers, thermoluminescent dosimeters, and Monte Carlo-based computational models, are reviewed and compared. The study emphasizes the importance of accurate dosimetric assessment for quality assurance, treatment planning, and radiation protection, highlighting current challenges and future directions in clinical photon beam dosimetry.