Dosimetric Study to Estimate Deviations in Delivered Radiation Dose due to Occluded Air Spaces in Vaginal Vault Brachytherapy Applications

Challapalli Srinivas, Sourjya Banerjee, Dilson Lobo, M. S. Athiyamaan, Ravichandran Ramamoorthy, Sunny Johan, Krishna Abhishek, Silpa Ajaykumar, Arun Kumar E S

Research output: Contribution to journalArticlepeer-review


BACKGROUND: To develop a dosimetric tool to estimate the dose delivered in the presence of air pockets with EBT3 film while simulating the conditions of vaginal vault brachytherapy (VVBT) with 3.0 diameter cylindrical applicator at a prescription dose distance of 5mm from the surface of it. MATERIALS AND METHOD: Six acrylic plates (10 cm x 10 cm, 0.5 cm thick) with four different types of slots were designed and produced locally. They can hold a cylindrical vaginal brachytherapy applicator in the centre, air equivalent material from the applicator's surface [(sizes 4.5 mm (A), 3.0 mm (B), and 2.0 mm (C)], EBT3 film at the prescribed dose distance, and holder rods. Plates were layered together with acrylic rods and assembled in a holding box in a water phantom. Three treatment plans done in TPS with prescription doses of 2 Gy, 3 Gy, and 4 Gy at 5.0 mm with a treatment length of 6 cm, and were executed in Co-60-based HDR brachytherapy unit (M/s SagiNova, Germany) with & without the placement of air equivalent material, and the dose received at slot locations A, B, & C were noted. RESULTS: The mean percentage deviation of measured dose without and with presence of air pocket at A, B and C was 13.9%, 11.0% and 6.4% respectively for all dose prescriptions. As the air pocket size expanded radially from 2.0 mm to 4.5 mm, the increase in dosage ranged from 6.4% to 13.9% which was due to the fact that the film was held at dosage prescription distance and the lack of attenuation of photons radially through air pocket. CONCLUSIONS: The present study can be carried out with a 3D printed phantom that simulates VVBT application having air pockets of different dimensions at different locations and also can be analyzed with Monte Carlo simulations.

Original languageEnglish
Pages (from-to)1659-1666
Number of pages8
JournalAsian Pacific journal of cancer prevention : APJCP
Issue number5
Publication statusPublished - 01-05-2023

All Science Journal Classification (ASJC) codes

  • Epidemiology
  • Oncology
  • Public Health, Environmental and Occupational Health
  • Cancer Research


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