title: Intensity-modulated radiotherapy of the prostate: dynamic ADC monitoring by DWI at 3.0 T.
abstract: OBJECTIVE
  Diffusion weighted imaging (DWI) as a functional MR technique allows for both qualitative and quantitative assessment of tumour cellularity and changes during therapy. The objective of this study was to evaluate changes of apparent diffusion coefficient (ADC) in biopsy proven prostate cancer (PCa) under intensity modulated radiotherapy (IMRT) at 3T.
  
  
  METHODS
  Thirteen patients with biopsy proven PCa treated with intensity modulated external beam radiotherapy (IMRT) underwent four standardized MR examinations after approval of the local institutional review board. These included DWI at 3T on a strict time table: before, in between, directly after (between 1 and 4 days after the last radiation), as well as 3 months after IMRT. Quantitative analysis of two different ADCs, - the ADC(0,800) and the ADC(50,800), was performed dynamically over 4 time points in PCa, gluteal muscle and healthy prostate tissue.
  
  
  RESULTS
  In PCa, a significant increase of ADC(0,800)/ADC(50,800) values was measured under IMRT by about 16%/15% (P=0.00008/0.00017), 21%/21% (P=0.00006/0.00030), and 33%/34% (P=0.00004/0.00002) at the three time points compared to initial value. Healthy prostate tissue did not show any significant increase.
  
  
  CONCLUSIONS
  DWI is suitable as a biomarker for radiation therapy response of PCa by allowing the dynamic monitoring of treatment effectiveness.
authors.affiliation: Department of Radiology, University of Bonn, Germany. Electronic address: georges.decker@ukb.uni-bonn.de.
authors.forename: Georges
authors.initials: G
authors.lastname: Decker
authors.affiliation: Department of Radiology, University of Bonn, Germany.
authors.forename: Petra
authors.initials: P
authors.lastname: Mürtz
authors.affiliation: Phillips Healthcare, Best, The Netherlands.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Gieseke
authors.affiliation: Department of Radiology, University of Bonn, Germany.
authors.forename: Frank
authors.initials: F
authors.lastname: Träber
authors.affiliation: Department of Radiology, University of Bonn, Germany.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Block
authors.affiliation: Department of Radiology, University of Bonn, Germany.
authors.forename: Alois M
authors.initials: AM
authors.lastname: Sprinkart
authors.affiliation: Department of Radiology, University of Bonn, Germany.
authors.forename: Christina
authors.initials: C
authors.lastname: Leitzen
authors.affiliation: Department of Radiology, University of Bonn, Germany.
authors.forename: Timo
authors.initials: T
authors.lastname: Buchstab
authors.affiliation: Department of Radiology, University of Bonn, Germany.
authors.forename: Christiana
authors.initials: C
authors.lastname: Lütter
authors.affiliation: Department of Radiology, University of Bonn, Germany.
authors.forename: Heinrich
authors.initials: H
authors.lastname: Schüller
authors.affiliation: Department of Radiology, University of Bonn, Germany.
authors.forename: Hans H
authors.initials: HH
authors.lastname: Schild
authors.affiliation: Department of Radiology, University of Bonn, Germany.
authors.forename: Winfried A
authors.initials: WA
authors.lastname: Willinek
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods; D006801:Humans; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D011446:Prospective Studies; D011468:Prostatectomy; D011471:Prostatic Neoplasms / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D050397:Radiotherapy, Intensity-Modulated; D016896:Treatment Outcome
keywords: 3T; DWI; IMRT; PCa