Implementation of needle‐tracking technology for real‐time transrectal ultrasound‐guided interstitial gynecological HDR brachytherapy: A feasibility study
Abstract
Purpose
To investigate the feasibility of adapting a commercial prostate biopsy system for transrectal ultrasound (TRUS)‐guided hybrid gynecological (GYN) high‐dose‐rate (HDR) brachytherapy (BT). Leveraging 3D‐TRUS and MR image fusion, the prototype system aims to improve real‐time needle placement accuracy.
Materials and Methods
A second‐generation, multi‐imaging modality female pelvic phantom was developed to validate the system's feasibility. Software and hardware modifications, including user‐accessible calibration modules and a redesigned needle guide for multi‐needle insertion, were made to the pre‐existing commercial system to enable use for GYN BT applications. An end‐to‐end feasibility test was performed to acquire 3D‐TRUS images, perform contour‐based registration with pre‐implant MR, and insert six needles to targeted locations under real‐time TRUS guidance. A 30° tandem without ovoids was added to mimic a hybrid GYN implant. The most proximal and most distal distances between the planned needle track and the visible portion of each inserted needle were measured. A CT/MR image‐based treatment plan with a prescribed dose of 6 Gy was generated for the resulting 3D‐TRUS‐guided implant (tandem and needles) within the phantom.
Results
The modified phantom improved needle visualization and insertion range by de‐gassing the silicone and increasing the window size. The system accuracy for average ± standard deviations from intended needle tracks was 1.31 ± 1.36 mm (proximal) and 2.04 ± 2.05 mm (distal). Post‐implant imaging confirmed needle placement and good target coverage. Needle placement was verified on CT/MR images and treatment plan quality was clinically acceptable.
Conclusions
With enhanced needle placement accuracy and integrated clinical workflow, this study demonstrates the feasibility of adapting a commercially available prostate biopsy system for 3D‐TRUS‐guided hybrid GYN HDR BT.