System for image guidance in breast-conserving surgery

In this thesis, a new system for breast-conserving surgery (BCS) is proposed to bracket the entire tumor by a virtual sphere that is centered at the location of a seed for radioactive seed localization (RSL). This system is composed of a dual-head gamma-camera (DHGC) system and a range-camera (RC) system. We have demonstrated that the DHGC system can be used to establish the location of the seed for RSL during BCS. Furthermore, the RC system can be combined with the DHGC system to visualize a virtual sphere that is centered on the location of the seed for RSL. The seed for RSL should be inserted as close as possible to the center of the tumor under the guidance of ultrasonography or mammography. The average distance between the center of the tumor and the location of the seed is 6 mm with a standard deviation of 3.4 mm. Because of this distance, seed-centered spheres are larger than tumor-centered spheres. Despite this disadvantage, it is expected that the seed-centered spheres are suitable target volumes for BCS, because the average volume of these spheres is smaller than the average excision volume after RSL that is reported in the literature. Consequently, we expect that the proposed system for image guidance has potential to improve RSL, and with that BCS.