Impact of computed tomography image quality on image-guided radiation therapy based on soft tissue registration. Int J Radiat Oncol Biol Phys 2012 Apr 01;82(5):e733-8
Date
02/22/2012Pubmed ID
22349041DOI
10.1016/j.ijrobp.2011.11.043Scopus ID
2-s2.0-84862816268 (requires institutional sign-in at Scopus site) 45 CitationsAbstract
PURPOSE: In image-guided radiation therapy (IGRT), different computed tomography (CT) modalities with varying image quality are being used to correct for interfractional variations in patient set-up and anatomy changes, thereby reducing clinical target volume to the planning target volume (CTV-to-PTV) margins. We explore how CT image quality affects patient repositioning and CTV-to-PTV margins in soft tissue registration-based IGRT for prostate cancer patients.
METHODS AND MATERIALS: Four CT-based IGRT modalities used for prostate RT were considered in this study: MV fan beam CT (MVFBCT) (Tomotherapy), MV cone beam CT (MVCBCT) (MVision; Siemens), kV fan beam CT (kVFBCT) (CTVision, Siemens), and kV cone beam CT (kVCBCT) (Synergy; Elekta). Daily shifts were determined by manual registration to achieve the best soft tissue agreement. Effect of image quality on patient repositioning was determined by statistical analysis of daily shifts for 136 patients (34 per modality). Inter- and intraobserver variability of soft tissue registration was evaluated based on the registration of a representative scan for each CT modality with its corresponding planning scan.
RESULTS: Superior image quality with the kVFBCT resulted in reduced uncertainty in soft tissue registration during IGRT compared with other image modalities for IGRT. The largest interobserver variations of soft tissue registration were 1.1 mm, 2.5 mm, 2.6 mm, and 3.2 mm for kVFBCT, kVCBCT, MVFBCT, and MVCBCT, respectively.
CONCLUSIONS: Image quality adversely affects the reproducibility of soft tissue-based registration for IGRT and necessitates a careful consideration of residual uncertainties in determining different CTV-to-PTV margins for IGRT using different image modalities.
Author List
Morrow NV, Lawton CA, Qi XS, Li XAAuthor
Natalya V. Morrow PhD Assistant Professor in the Radiation Oncology department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
Cone-Beam Computed TomographyConnective Tissue
Humans
Male
Observer Variation
Patient Positioning
Prostatic Neoplasms
Radiotherapy Planning, Computer-Assisted
Radiotherapy, Image-Guided
Reproducibility of Results
Tomography, X-Ray Computed
