title: An automated method for adaptive radiation therapy for prostate cancer patients using continuous fiducial-based tracking.
abstract: Electromagnetic tracking technology is primarily used for continuous prostate localization during radiotherapy, but offers potential value for evaluation of dosimetric coverage and adequacy of treatment for dynamic targets. We developed a highly automated method for daily computation of cumulative dosimetric effects of intra- and inter-fraction target motion for prostate cancer patients using fiducial-based electromagnetic tracking. A computer program utilizing real-time tracking data was written to (1) prospectively determine appropriate rotational/translational motion limits for patients treated with continuous isocenter localization; (2) retrospectively analyze dosimetric target coverage after daily treatment, and (3) visualize three-dimensional rotations and translations of the prostate with respect to the planned target volume and dose matrix. We present phantom testing and a patient case to validate and demonstrate the utility of this application. Gamma analysis of planar dose computed by our application demonstrated accuracy within 1%/1 mm. Dose computation of a patient treatment revealed high variation in minimum dose to the prostate (D(min)) over 40 fractions and a drop in the D(min) of approximately 8% between a 5 mm and a 3 mm PTV margin plan. The infrastructure has been created for patient-specific treatment evaluation using continuous tracking data. This application can be used to increase confidence in treatment delivery to targets influenced by motion.
authors: Department of Radiation Oncology, Washington University School of Medicine, 4921 Parkview Place, St Louis, MO 63110, USA.
authors: C E
authors: CE
authors: Noel
authors: L
authors: L
authors: Santanam
authors: J R
authors: JR
authors: Olsen
authors: K W
authors: KW
authors: Baker
authors: P J
authors: PJ
authors: Parikh
mesh_terms: D001331:Automation / Q000295:instrumentation / Q000379:methods*; D004574:Electromagnetic Fields; D006801:Humans; D008297:Male; D008954:Models, Biological; D009038:Motion; D019047:Phantoms, Imaging; D011471:Prostatic Neoplasms / Q000532:radiotherapy*; D011874:Radiometry / Q000295:instrumentation / Q000379:methods; D011878:Radiotherapy / Q000295:instrumentation / Q000379:methods*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000295:instrumentation / Q000379:methods; D050397:Radiotherapy, Intensity-Modulated / Q000295:instrumentation / Q000379:methods; D012399:Rotation; D012984:Software; D013997:Time Factors