title: Clinical commissioning of online seed matching protocol for prostate radiotherapy.
abstract: OBJECTIVE
  Our aim was to clinically commission an online seed matching image-guided radiotherapy (IGRT) protocol using modern hardware/software for patients undergoing prostate radiotherapy. An essential constraint was to achieve this within a busy centre without reducing patient throughput, which had been reported with other techniques.
  
  
  METHODS
  45 patients had 3 fiducial markers inserted into the prostate and were imaged daily using kilovoltage orthogonal images with online correction applied before treatment. A total of 1612 image pairs were acquired and analysed to identify interfractional motion, seed migration and interobserver variability, and assess ease of use.
  
  
  RESULTS
  This method of IGRT was implemented successfully in our centre with no impact on treatment times and patient throughput. Systematic (Σ) interfractional set-up errors were 2.2, 2.7 and 3.9 mm in right-left (RL), superoinferior (SI) and anteroposterior (AP) directions, respectively. Random (σ) interfractional set-up errors were 3.2 (RL), 3.7 (SI) and 5.7 mm (AP). There were significant differences between patients. Seed migration and interobserver variability were not significant issues.
  
  
  CONCLUSIONS
  The described technique is facilitated by the advanced imaging system, allowing a fast and effective method of correcting set-up errors before treatment. Extended implementation of this technique has improved treatment delivery to the majority of our prostate radiotherapy patients. The measurement of interfractional motion in this study is potentially valuable for margin reduction in intensity-modulated radiotherapy/volumetric arc therapy.
  
  
  CONCLUSIONS
  This technique can be used within treatment time constraints, benefiting large numbers of patients by helping to avoid geographical miss and potentially reducing toxicity to organs at risk.
authors.affiliation: Department of Radiotherapy, Beatson West of Scotland Cancer Centre, Glasgow, UK. aileen.duffton@ggc.scot.nhs.uk
authors.forename: A
authors.initials: A
authors.lastname: Duffton
authors.forename: S
authors.initials: S
authors.lastname: McNee
authors.forename: R
authors.initials: R
authors.lastname: Muirhead
authors.forename: A
authors.initials: A
authors.lastname: Alhasso
mesh_terms: D002985:Clinical Protocols; D057918:Fiducial Markers; D005548:Foreign-Body Migration / Q000209:etiology; D006801:Humans; D008297:Male; D008505:Medical Staff, Hospital / Q000193:education; D015588:Observer Variation; D019047:Phantoms, Imaging; D011471:Prostatic Neoplasms / Q000532:radiotherapy*; D011785:Quality Assurance, Health Care; D011871:Radiology / Q000193:education; D011881:Radiotherapy, Computer-Assisted; D061089:Radiotherapy, Image-Guided / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000379:methods