UroLift implants as surrogate fiducial markers for cone-beam CT-based prostate image-guided radiotherapy

Abstract

Introduction: UroLift implants are a novel treatment for the obstructive lower urinary tract symptoms arising from benign prostatic hyperplasia. This case study aimed to assess their effectiveness as fiducial marker (FM) surrogates in prostate image-guided radiotherapy (IGRT). Method: Cone-beam CT images from a patient receiving prostate radiation therapy underwent manual alignment using UroLift implants and also prostate soft-tissue matching by five experienced therapeutic radiographers. The match values of both methods were compared using Bland–Altman analysis. All five observers were also asked to score the ease of matching using both approaches. Results: The 95% mean level of agreement for the UroLift matches were within a 2-mm threshold in all dimensions. Comparison of UroLift and prostate matches had 95% limit of agreement values of −0·98 to 1·78, −0·58 to 0·49 and −1·83 to 1·04 mm in the vertical, longitudinal and lateral planes, respectively. All of the UroLift matches were rated as ‘very easy’ or ‘possible with little difficulty’ by the five observers. Conclusion: A small difference between the CBCT UroLift and CBCT prostate match was found. It has been shown that IGRT to the prostate with the aid of the UroLift system implants and CBCT is feasible and can eliminate the need for FM implants. Wider evaluation in a large cohort is recommended.