title: Improved dosimetry in prostate brachytherapy using high resolution contrast enhanced magnetic resonance imaging: a feasibility study.
abstract: OBJECTIVE
  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).
  
  
  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.
authors.affiliation: Department of Radiology, Boston University Medical Center, Boston, USA.
authors.forename: Karen
authors.initials: K
authors.lastname: Buch
authors.affiliation: Department of Radiation Oncology, Beth Israel Deaconess Medical Center, Boston, USA.
authors.forename: Tye
authors.initials: T
authors.lastname: Morancy
authors.affiliation: Department of Radiation Oncology, Beth Israel Deaconess Medical Center, Boston, USA.
authors.forename: Irving
authors.initials: I
authors.lastname: Kaplan
authors.affiliation: Department of Radiation Oncology, Boston University Medical Center, Boston, USA.
authors.forename: Muhammad M
authors.initials: MM
authors.lastname: Qureshi
authors.affiliation: Department of Radiation Oncology, Boston University Medical Center, Boston, USA.
authors.forename: Ariel E
authors.initials: AE
authors.lastname: Hirsch
authors.affiliation: Department of Radiology, University of Texas Southwestern, Dallas, USA.
authors.forename: Neil M
authors.initials: NM
authors.lastname: Rofksy
authors.affiliation: Department of Radiation Oncology, Beth Israel Deaconess Medical Center, Boston, USA.
authors.forename: Edward
authors.initials: E
authors.lastname: Holupka
authors.affiliation: Institute for Radio-Oncology, Danube Hospital, Vienna, Austria.
authors.forename: Renee
authors.initials: R
authors.lastname: Oismueller
authors.affiliation: Institute for Radio-Oncology, Danube Hospital, Vienna, Austria.
authors.forename: Robert
authors.initials: R
authors.lastname: Hawliczek
authors.affiliation: Department of Radiology, Division of Gender and Molecular Imaging, Medical University Vienna, Vienna, Austria.
authors.forename: Thomas H
authors.initials: TH
authors.lastname: Helbich
authors.affiliation: Department of Radiology, Boston University Medical Center, Boston, USA.
authors.forename: B Nicolas
authors.initials: BN
authors.lastname: Bloch
keywords: brachytherapy; dosimetry; high resolution contrast enhanced MRI; prostate; prostate cancer
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