Navigation en temps-réel pour la biopsie de prostate

Abstract

Prostate cancer is the most common cancer world-wide for males and the second leading cause of cancer death in France. Prostate biopsy procedures, performed to obtain and analyze tissue samples of the gland, are required for diagnosis. The clinical standard protocol is currently performed under UltraSound (US) control following a systematic protocol. Unfortunately, prostate cancer diagnosis is complicated by the lack of image quality and the low intrinsic contrast between tumor and non-tumor on US images. Conventional biopsies are performed under Transrectal UltraSound (TRUS) guidance. Precisely localizing the biopsy sites is challenging because the gland has a symmetric shape and because the prostate moves and is deformed by the patient motion and the TRUS probe pressure.This work aims at designing a system for navigated prostate biopsies combining a low-cost tracking system and a 2D-3D US registration method. To achieve this objective, our approach is based on hybrid 2D-3D ultrasound (US) rigid registration method for navigated prostate biopsy that enables continuous localization of the biopsy trajectory during the exam.Accuracy and robusteness was evaluated on a significant patient data set recorded in routine uncontrolled conditions from two different hospitals. The results show that 75% of the cases with error less than 5mm, which is clinically acceptable.Thereafter, we developed experiments to evaluate the tracking. The method was tested in a prostate phantom and a probe tracking by a inertial sensor. It was shown that it can do a better localization than and inertial measurement unit. Those first results obtained by our tracking method have established a proof of concept for a future clinical application. We highlighted that the sensor data are complex to exploit in optimal conditions. Additional experiments sould be performed in more realistic conditions.The method adjustment and the computing time-enhancement are the two main approaches to develop to create a first prototype of real-time tracking for navigated prostate biopsy. The long-standing cooperation between clinicians and researchers is an essential asset for a future clinical validation.