Brachytherapy is one the most effective treatment modalities for both gynecological (GYN) cancer and prostate cancer. The clinical outcome of brachytherapy, both high-dose-rate (HDR) and low-dose-rate (LDR), depends on the precision of the desired or planned dose distribution and delivery. In HDR procedure, the accuracy of reconstruction of catheters or needles (e.g. Syed catheter or Simon-Heyman capsule for GYN or needles for prostate) from CT images can significantly affect the accuracy of dose distribution in the treatment (dosimetric) plan, which can result in unwanted clinical outcome. In current practice, an authorized medical physicist manually reconstructs the catheters or needles for dosimetric plan, which determines the position and dwell time for the radiation source for delivering the prescription dose to the target volume sparing organs at risk (OARs) as much as possible. It is not only challenging but also time consuming for reconstructing all the catheters or needles (ranging 15–20) manually, slice-by-slice in CT images. As shown in Fig. 1, the needles on the right (HDR catheters) have created so much artifacts in CT images that it is almost impossible to reconstruct those applicators (catheters/ needles) manually. Additionally, the reconstruction can be operator dependent and can be inaccurate and inconsistent.
In this study, we have investigated the applicability of electromagnetic (EM) sensor-based navigation for fast and accurate reconstruction of HDR catheters and needles.