What is your approach for post-implant dosimetry when utilizing a focal LDR prostate implant for salvage after a localized primary LDR brachytherapy failure?

We have recently done a few patients with LDR brachy after primary EBRT failure. MRI showed disease localized to one lobe and thus we implanted half of prostate. The d90 for implanted region we aimed for was 100% but two precautions we took were: one avoid bladder neck region and second use space OA...