Anastasiia Mishchenko MSc, Presenter: Institutional research collaboration, Analogic Corporation

Olivier Tousignant PhD, Abstract Co-Author: Employee, Analogic Corporation

Aram Teymurazyan PhD, Abstract Co-Author: Research collaboration, Analogic Corporation

Ananth Ravi PhD, Abstract Co-Author: Nothing to Disclose

Alla Reznik PhD, Abstract Co-Author: Research partner, Analogic Canada Corporation Research partner, Koninklijke Philips NV

Implementation of our gamma-camera for PBSI has the potential to significantly improve the accuracy of radioactive seeds implantation, which may increase the adoption of the procedure thereby potentially improving breast cancer patients quality of life.

Permanent Breast Seed Implantation (PBSI) is an innovative method of accelerated partial breast irradiation for post-operative treatment of early breast cancer. It has the potential to improve the quality of life of breast cancer patients as it avoids protracted radiation treatments and acute skin reaction. The technique involves permanent implantation of 80-90 small 103-Palladium radioactive seeds into the breast (PBSI) at the lumpectomy cavity to deliver precisely calculated radiation doses to the target volume with a safety margin. To date more than 150 patients were accrued into clinical trials with favorable outcomes. However, the implementation of PBSI into widespread routine practice would greatly benefit from a development of a dedicated device that guides seed implantation and evaluates the dose distribution during and at the end of the implantation. Here we evaluate the ability to localize radioactive seeds with a novel dedicated gamma-camera prototype vs. clinical requirements.  

Imaging performance has been evaluated with realistic breast phantoms mimicking dense breast tissue and fatty breast tissue, and simulated PBSI procedure. The breast phantom thickness was varied from 1 to 6 cm and from 1 to 5 brachytherapy sources wereseparated by 0.5, 1, 2 cm. In order to quantify the camera response, the breast phantom with implanted seeds was placed in front of collimator face. All seeds at all separations and depths are clearly distinguishable visually.  The profiles of the seeds in the images were fit with a Gaussian distrbution in both phantoms, from which the positions of the sources were derived.

The requirements of the prototype system is that it will be able to distinguish seeds placed 5mm and greater from each other within an imaging time window of 2 min. Our studies show that the evaluated gamma-camera has adequate spatial resolution and sensitivity, which fulfills these clinical requirements.

Mishchenko, A, Tousignant, O, Teymurazyan, A, Ravi, A, Reznik, A, Gamma-Camera for Image-guided Low-energy Breast Brachytherapy .  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14018523.html