BACKGROUND AND PURPOSE: (1) To establish a method to evaluate dosimetry at the time of primary prostate permanent implant (pPPI) using MRI of the shrunken prostate at the time of failure (tf). (2) To compare cold spot mapping with sextant-biopsy mapping at tf. MATERIAL AND METHODS: Twenty-four patients were referred for biopsy-proven local failure (LF) after pPPI. Multiparametric MRI and combined-sextant biopsy with a central review of the pathology at tf were systematically performed. A model of the shrinking pattern was defined as a Volumetric Change Factor (VCF) as a function of time from time of pPPI (t0). An isotropic expansion to both prostate volume (PV) and seed position (SP) coordinates determined at tf was performed using a validated algorithm using the VCF. RESULTS: pPPI CT-based evaluation (at 4weeks) vs. MR-based evaluation: Mean D90% was 145.23±19.16Gy [100.0-167.5] vs. 85.28±27.36Gy [39-139] (p=0.001), respectively. Mean V100% was 91.6±7.9% [70-100%] vs. 73.1±13.8% [55-98%] (p=0.0006), respectively. Seventy-seven per cent of the pathologically positive sextants were classified as cold. CONCLUSIONS: Patients with biopsy-proven LF had poorer implantation quality when evaluated by MRI several years after implantation. There is a strong relationship between microscopic involvement at tf and cold spots.
BACKGROUND AND PURPOSE: (1) To establish a method to evaluate dosimetry at the time of primary prostate permanent implant (pPPI) using MRI of the shrunken prostate at the time of failure (tf). (2) To compare cold spot mapping with sextant-biopsy mapping at tf. MATERIAL AND METHODS: Twenty-four patients were referred for biopsy-proven local failure (LF) after pPPI. Multiparametric MRI and combined-sextant biopsy with a central review of the pathology at tf were systematically performed. A model of the shrinking pattern was defined as a Volumetric Change Factor (VCF) as a function of time from time of pPPI (t0). An isotropic expansion to both prostate volume (PV) and seed position (SP) coordinates determined at tf was performed using a validated algorithm using the VCF. RESULTS:pPPI CT-based evaluation (at 4weeks) vs. MR-based evaluation: Mean D90% was 145.23±19.16Gy [100.0-167.5] vs. 85.28±27.36Gy [39-139] (p=0.001), respectively. Mean V100% was 91.6±7.9% [70-100%] vs. 73.1±13.8% [55-98%] (p=0.0006), respectively. Seventy-seven per cent of the pathologically positive sextants were classified as cold. CONCLUSIONS:Patients with biopsy-proven LF had poorer implantation quality when evaluated by MRI several years after implantation. There is a strong relationship between microscopic involvement at tf and cold spots.
Authors: Supriya Chopra; Ants Toi; Nathan Taback; Andrew Evans; Masoom A Haider; Michael Milosevic; Robert G Bristow; Peter Chung; Andrew Bayley; Gerard Morton; Danny Vesprini; Padraig Warde; Charles Catton; Cynthia Ménard Journal: Int J Radiat Oncol Biol Phys Date: 2012-03-01 Impact factor: 7.038
Authors: Marco van Vulpen; Cornelis A T van den Berg; Maaike R Moman; Uulke A van der Heide Journal: Radiother Oncol Date: 2009-08-21 Impact factor: 6.280
Authors: Elnasif Arrayeh; Antonio C Westphalen; John Kurhanewicz; Mack Roach; Adam J Jung; Peter R Carroll; Fergus V Coakley Journal: Int J Radiat Oncol Biol Phys Date: 2012-02-11 Impact factor: 7.038
Authors: Marisol De Brabandere; Peter Hoskin; Karin Haustermans; Frank Van den Heuvel; Frank-André Siebert Journal: Radiother Oncol Date: 2012-07-31 Impact factor: 6.280