title: Learning curve of MRI-based planning for high-dose-rate brachytherapy for prostate cancer.
abstract: To evaluate introduction of MRI-based high-dose-rate brachytherapy (HDRBT), including procedure times, dose-volume parameters, and perioperative morbidity.
  
  
  
  Study included 42 high-risk prostate cancer patients enrolled in a clinical protocol, offering external beam radiotherapy + two HDRBT 8.5 Gy boosts. Time was recorded for initiation of anesthesia (A), fixation of needle implant (B), end of MR imaging (C), plan approval (D), and end of HDRBT delivery (E). We defined time A-E as total procedure time, A-B as operating room time, B-C as MRI procedure time, C-D as treatment planning time, and D to E as treatment delivery time. Dose-volume parameters were retrieved from the dose planning system. Results from the first 21 patients were compared with the last 21 patients.
  
  
  
  Total procedure time, operating room time, MRI procedure time, and treatment planning time decreased significantly from average 7.6 to 5.3 hours (p < 0.01), 3.6 to 2.4 hours (p < 0.01), 1.6 to 0.8 hours (p < 0.01), and 2.0 to 1.3 hours (p < 0.01), respectively. HDRBT delivery time remained unchanged at 0.5 hours. Clinical target volume prostate+3mmD90 fulfilled planning aim in 92% of procedures and increased significantly from average 8.3 to 9.0 Gy (p < 0.01). Urethral D0.1 cm(3) and rectal D2 cm(3) fulfilled planning aim in 78% and 95% of procedures, respectively, and did not change significantly. Hematuria occurred in (95%), hematoma (80%), moderate to strong pain (35%), and urinary retention (5%) of procedures.
  
  
  
  After introduction of MRI-based HDRBT, procedure times were significantly reduced. D90 Clinical target volumeprostate+3mm fulfilled constraints in most patients and improved over time, but not at expense of an increased urethral or rectal dose.
authors.affiliation: Department of Oncology, Aarhus University Hospital, Aarhus, Denmark. Electronic address: simbuu@rm.dk.
authors.forename: Simon
authors.initials: S
authors.lastname: Buus
authors.affiliation: Department of Oncology, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Susanne
authors.initials: S
authors.lastname: Rylander
authors.affiliation: Department of Oncology, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Steffen
authors.initials: S
authors.lastname: Hokland
authors.affiliation: Department of Oncology, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Christian Skou
authors.initials: CS
authors.lastname: Søndergaard
authors.affiliation: Department of Radiology, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Erik Morre
authors.initials: EM
authors.lastname: Pedersen
authors.affiliation: Department of Oncology, Aarhus University Hospital, Aarhus, Denmark; Department of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Kari
authors.initials: K
authors.lastname: Tanderup
authors.affiliation: Department of Oncology, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Lise
authors.initials: L
authors.lastname: Bentzen
mesh_terms: D000368:Aged; D001918:Brachytherapy / Q000009:adverse effects / Q000379:methods*; D006417:Hematuria / Q000209:etiology; D006801:Humans; D059032:Learning Curve; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009339:Needles; D061646:Operative Time; D058958:Organs at Risk / Q000000981:diagnostic imaging; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D012007:Rectum / Q000000981:diagnostic imaging; D014521:Urethra / Q000000981:diagnostic imaging; D001743:Urinary Bladder / Q000000981:diagnostic imaging; D016055:Urinary Retention / Q000209:etiology; D057188:Workflow
keywords: HDR; Learning curve; MRI; Morbidity; Prostate cancer; Workflow