Improved dosimetry in prostate brachytherapy using high resolution contrast enhanced magnetic resonance imaging: A feasibility study - Abstract

PURPOSE: To assess detailed dosimetry data for prostate and clinical relevant intra- and peri-prostatic structures including neurovascular bundles (NVB), urethra, and penile bulb (PB) from postbrachytherapy computed tomography (CT) versus high resolution contrast enhanced magnetic resonance imaging (HR-CEMRI).

MATERIAL AND METHODS: Eleven postbrachytherapy prostate cancer patients underwent HR-CEMRI and CT imaging. Computed tomography and HR-CEMRI images were randomized and 2 independent expert readers created contours of prostate, intra- and peri-prostatic structures on each CT and HR-CEMRI scan for all 11 patients. Dosimetry data including V100, D90, and D100 was calculated from these contours.

RESULTS: Mean V100 values from CT and HR-CEMRI contours were as follows: prostate (98.5% and 96.2%, p = 0.003), urethra (81.0% and 88.7%, p = 0.027), anterior rectal wall (ARW) (8.9% and 2.8%, p < 0.001), left NVB (77.9% and 51.5%, p = 0.002), right NVB (69.2% and 43.1%, p = 0.001), and PB (0.09% and 11.4%, p = 0.005). Mean D90 (Gy) derived from CT and HR-CEMRI contours were: prostate (167.6 and 150.3, p = 0.012), urethra (81.6 and 109.4, p = 0.041), ARW (2.5 and 0.11, p = 0.003), left NVB (98.2 and 58.6, p = 0.001), right NVB (87.5 and 55.5, p = 0.001), and PB (11.2 and 12.4, p = 0.554).

CONCLUSIONS: Findings of this study suggest that HR-CEMRI facilitates accurate and meaningful dosimetric assessment of prostate and clinically relevant structures, which is not possible with CT. Significant differences were seen between CT and HR-CEMRI, with volume overestimation of CT derived contours compared to HR-CEMRI.

Written by:
Buch K, Morancy T, Kaplan I, Qureshi MM, Hirsch AE, Rofksy NM, Holupka E, Oismueller R, Hawliczek R, Helbich TH, Bloch BN.   Are you the author?
Department of Radiology, Boston University Medical Center, Boston, USA; Department of Radiation Oncology, Beth Israel Deaconess Medical Center, Boston, USA; Department of Radiation Oncology, Boston University Medical Center, Boston, USA; Department of Radiology, University of Texas Southwestern, Dallas, USA; Institute for Radio-Oncology, Danube Hospital, Vienna, Austria; Department of Radiology, Division of Gender and Molecular Imaging, Medical University Vienna, Vienna, Austria.

Reference: J Contemp Brachytherapy. 2015 Jan;6(4):337-43.
doi: 10.5114/jcb.2014.46555


PubMed Abstract
PMID: 25834576

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