Method and Materials: An Ir‐192 line source was simulated using Plato treatment planning software to administer 6 Gy at the surface of a vaginal applicator. A series of reference points were generated to identify the dose drop‐off axially, as well as in the anisotropy region. The treatment plan was then used to irradiate the PRESAGE™ polymer dosimeter. The dosimeter was subsequently evaluated using the Vista Optical CT Scanner (Modus Medical Devices Inc.) in conjunction with VistaRecon™ software (Bosi et al 2007). Comparisons were made between the three‐dimensional optical measurements, the treatment plan and Monte Carlo simulations using the PENELOPE. Results: Good comparative agreement was found. The dose agreement in the axial direction from the PRESAGE and TPS was within 4% up to 2cm from the surface of the applicator. Conclusion: The PRESAGE™ dosimeter was shown to have potential as a three‐dimensional dosimeter for use with IMRT, conformal and brachytherapy radiotherapy treatment verification. Reference: Bosi SG, Naseri P, Puran A, Davies J, Baldock C, 2007. Initial investigation of a novel light‐scattering gel phantom for evaluation of optical CT scanners for radiotherapy gel dosimetry. Phys. Med. Biol. 52 2893–2903. © 2008, American Association of Physicists in Medicine. All rights reserved.