Endoscopic Guided Brachytherapy in Gastric Cancer

The purpose of this study is to examine the feasibility of treating patients with unresectable advanced gastric cancer using high dose rate (HDR) brachytherapy method and via an endoscope. The procedure was done by an ordinary gastroscope. Adding some tubes around it made the passage of brachytherapy applicators possible. A needle on the tip of the designed applicator allowed insertion to the tumor depth. The treatment implementation was evaluated on a gastric tract simulator phantom. Treatment planning of the determined clinical target volume (CTV) and two organs at risk (OARs) in the phantom showed 93.6% coverage of CTV while 90% of OARs received about one third of the prescribed dose. Since the applicator was not a tested one, some dosimetry experiments were done as well. These trials showed a correlation coefficient of 99.24% between the proposed applicator and a standard interstitial one. We concluded that endoscopic guided brachytherapy of gastric cancer using 192Ir source and the proposed applicator is feasible. Although the results were acceptable, clinical trials are inevitable to examine the efficacy of this new treatment modality.