SU-E-T-320: A New Verification Phantom for GYN Brachytherapy Applicators Using GafChromic - Films

Area of Science:

• Medical Physics
• Radiation Oncology
• Brachytherapy

Background:

• Brachytherapy is crucial for treating gynecological cancers like vaginal, cervical, and endometrial.
• Accurate dosimetry is essential for effective radiation therapy and minimizing side effects.

Purpose of the Study:

• To design, fabricate, and verify a novel phantom for precise dosimetric verification.
• To assess dose accuracy at small distances from gynecological (GYN) applicators using a Cobalt-60 High Dose Rate (HDR) system (GZP6).

Main Methods:

• A phantom was constructed from 90 Perspex slabs to house GYN applicators.
• GafChromic films were placed between slabs for dosimetry measurements with the GZP6 system.
• Film dosimetry results were compared against treatment planning software calculations.

Main Results:

• The study identified dose discrepancies of up to ±23% between planned and measured dosimetry.
• The developed phantom successfully confirmed the accuracy of radiation delivery for GYN patients.

Conclusions:

• The new phantom is suitable for Quality Assurance (QA) of Cobalt-60 HDR and Iridium-192 HDR systems.
• It enhances the confirmation of accurate dose distribution in GYN implants, including non-traditional ones.