Comparison and Evaluation of Different Radiotherapy Techniques Using Biodosimetry Based on Cytogenetics

Area of Science:

• Radiation oncology
• Medical physics
• Cytogenetics

Background:

• Technological advancements in radiotherapy aim for precise radiation delivery and reduced side effects.
• Evaluating the biological dose and radiobiological impact of prolonged radiotherapy is crucial.
• Comparing advanced techniques (VMAT, IMRT) with conventional 3D-CRT using biological dosimetry is needed.

Purpose of the Study:

• To compare the biological dose delivered by volumetric modulated arc therapy (VMAT) and intensity-modulated radiation therapy (IMRT) against conventional 3D-CRT.
• To investigate the radiobiological impact of protracted radiotherapy treatment duration.
• To assess radiotherapy efficacy using cytogenetic biodosimetry.

Main Methods:

• Utilized a dicentric biodosimetry assay on peripheral blood lymphocytes from prostate cancer patients and the PC3 cell line.
• Irradiated samples using 3D-CRT, IMRT, and VMAT techniques.
• Estimated absorbed dose by scoring dicentric chromosome frequencies.

Main Results:

• IMRT and VMAT showed a statistically significant ~6% underestimation of the biological absorbed dose compared to 3D-CRT in lymphocytes.
• VMAT and IMRT results were comparable, with VMAT showing slightly lower values.
• Similar underestimation trends were observed using the PC3 cell line.

Conclusions:

• Modulated radiotherapy techniques (IMRT, VMAT) may deliver a lower biological dose than 3D-CRT.
• The observed underestimation might be linked to the lower dose rate and longer irradiation times in VMAT and IMRT.
• Biodosimetry is a valuable tool for evaluating the radiobiological effectiveness of different radiotherapy techniques.