Robot-gestuurde plaatselijke inwendige bestraling voor de behandeling van patiënten met teruggekeerde prostaatkanker.

For patients with localized radiorecurrent prostate cancer, focal treatment has the potential to maintain cancer control with less treatment-related toxicity than whole-gland salvage treatments. High-dose-rate brachytherapy (HDR-BT) is a suitable modality for focal salvage treatment. For brachytherapy needle insertion, the prostate is directly visualised using trans-rectal ultrasound, whereas the target tumour volume is visualised indirectly through delineations from a pre-radiation MRI scan which are fused with the TRUS images. This is a shortcoming in the current workflow, because it requires registration of pre-operative MR-images to live intra-operative TRUS images. This registration becomes less accurate during needle implantation as the firm prostate tissue is displaced and deformed due to edema. However, since space is limited within the MRI bore itself, manual brachytherapy needle insertion under real-time MRI guidance is physically impossible.
To overcome this, a robotic MRI-compatible implantation device was developed to perform focal salvage HDR-BT under direct MRI-guidance. The robot fits in a 1.5T MRI scanner and can be placed between the patient’s legs. The accuracy of the device was tested in air and in an agar phantom, with promising results regarding needle alignment. We anticipate that the tested image-based workflow is also feasible for in vivo validation of the robotic device.
Prior to the standard manual implantation procedure, a single needle will be introduced into the prostate by the robot and a radiation dose will be delivered.

A robotic MRI-compatible brachytherapy implantation device was developed to perform needle insertion under real-time MRI guidance. The purpose of this study is to investigate the technical feasibility of inserting a brachytherapy needle into the prostate to a defined tumour target point using this robotic device. With promising results regarding needle alignment after testing in phantoms, it is expected that this will be feasible in vivo as well.

4 weeks (assessment of treatment toxicity)

Single-needle insertion into the prostate by an MR-compatible robotic device, prior to the conventional manual focal salvage high-dose-rate brachytherapy procedure.