Radiation protection considerations for endocavitary X ray units

Area of Science:

• Medical Physics
• Oncology
• Radiotherapy

Background:

• Endocavitary irradiation using contact X-ray therapy units is an emerging treatment for selected rectal carcinomas.
• This technique involves precise application of X-rays directly within the rectal cavity.

Purpose of the Study:

• To evaluate the dosimetry and radiation safety aspects of endocavitary X-ray therapy for rectal cancer.
• To assess radiation exposure levels for healthcare professionals during the procedure.

Main Methods:

• Utilized a contact X-ray therapy unit with a 50 kVp X-ray source filtered by 1.0 mm aluminum.
• Measured the half-value layer (HVL) and dose rate at a 4.0 cm source-skin-distance (SSD).
• Conducted radiation surveys at various positions around the patient during simulated treatment geometries.

Main Results:

• The measured HVL was 0.65 mm of aluminum.
• The dose rate at the SSD cone reached approximately 1000 rad/minute.
• Radiation exposure levels for personnel ranged from 0.001 to 1.0 roentgen per hour, varying with X-ray tube depth and angle.

Conclusions:

• Contact X-ray therapy provides high localized doses for rectal cancer treatment.
• Significant radiation exposure potential exists for staff, necessitating careful radiation protection measures.
• Further optimization of treatment protocols and shielding may be required to minimize occupational exposure.