Photon dose rate distribution inside and outside a brachytherapy room.

Area of Science:

• Medical Physics
• Radiation Oncology
• Nuclear Engineering

Background:

• Brachytherapy utilizes sealed radioactive sources for cancer treatment.
• Accurate assessment of radiation dose distribution is crucial for patient safety and staff protection.
• Shielding design for brachytherapy rooms requires precise dose rate measurements and simulations.

Purpose of the Study:

• To measure and calculate spatial photon dose rates inside and outside an Iridium-192 brachytherapy room.
• To validate simulation methods for brachytherapy room radiation shielding.
• To propose recommendations for optimizing radiation protection measures.

Main Methods:

• Photon dose rates were measured using thermoluminescent dosimeters (LiF-100) on room surfaces.
• Calculations were performed using the Particle and Heavy Ion Transport Code System (PHITS).
• A detailed model of the brachytherapy room and the 192Ir source was employed for simulations.

Main Results:

• Measured and calculated dose distributions showed similar patterns both inside and outside the room.
• A good agreement was observed between experimental measurements and PHITS simulations.
• A 3-mm lead layer on the entrance door's concrete wall is recommended to mitigate edge effects.

Conclusions:

• The PHITS code accurately simulates photon dose rates in brachytherapy environments.
• Shielding modifications, such as adding lead layers, can effectively reduce radiation exposure.
• Further studies are needed to evaluate shielding effectiveness for different isotopes like Cobalt-60.