title: Application of Spatially Fractionated Radiation (GRID) to Helical Tomotherapy using a Novel TOMOGRID Template.
abstract: Spatially fractionated radiation therapy (GRID) with megavoltage x-ray beam is typically used to treat large and bulky malignant tumors. Currently most of the GRID treatment is performed by using the linear accelerator with either the multileaf collimator or with the commercially available block. A novel method to perform GRID treatments using Helical Tomotherapy (HT) was developed at the Radiation Oncology Department, College of Medicine, the University of Arkansas for Medical Sciences. In this study, we performed a dosimetric comparison of two techniques of GRID therapy: one on linear accelerator with a commercially available GRID block (LINAC-GRID) as planned on the Pinnacle planning station (P-TPS); and helical tomotherapy-based GRID (HT-GRID) technique using a novel virtual TOMOGRID template planned on Tomotherapy treatment planning station (HT-TPS). Three dosimetric parameters: gross target volume (GTV) dose distribution, GTV target dose inhomogeneity, and doses to regions of interest were compared. The comparison results show that HT-GRID dose distributions are comparable to those of LINAC-GRID for GTV coverage. Doses to the majority of organs-at-risk (OAR) are lower in HT-GRID as compared to LINAC-GRID. The maximum dose to the normal tissue is reduced by 120% for HT-GRID as compared to the LINACGRID. This study indicate that HT-GRID can be used to deliver spatially fractionated dose distributions while allowing 3-D optimization of dose to achieve superior sparing of OARs and confinement of high dose to target.
authors.affiliation: Department of Radiation Oncology, University of Arkansas for Medical Sciences, 4301 W. Markham St., #771, Little Rock, AR 72205 xzhang2@uams.edu.
authors.forename: X
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department of Radiation Oncology, University of Arkansas for Medical Sciences, 4301 W. Markham St., #771, Little Rock, AR 72205.
authors.forename: J
authors.initials: J
authors.lastname: Penagaricano
authors.affiliation: Department of Radiation Oncology, UT Southwestern Medical Center, 5801 Forest Park Road, Dallas, TX 75235-8542.
authors.forename: Y
authors.initials: Y
authors.lastname: Yan
authors.affiliation: Department of Radiation Oncology, University of Arkansas for Medical Sciences, 4301 W. Markham St., #771, Little Rock, AR 72205.
authors.forename: S
authors.initials: S
authors.lastname: Sharma
authors.affiliation: Department of Radiation Oncology, University of Arkansas for Medical Sciences, 4301 W. Markham St., #771, Little Rock, AR 72205 Experimental Therapeutics Program, University of Arkansas for Medical Sciences, Winthrop P. Rockefeller Cancer Institute, 4018 W. Capitol Avenue, Little Rock, Arkansas 72205.
authors.forename: R J
authors.initials: RJ
authors.lastname: Griffin
authors.affiliation: Department of Radiation Oncology, University of Arkansas for Medical Sciences, 4301 W. Markham St., #771, Little Rock, AR 72205.
authors.forename: M
authors.initials: M
authors.lastname: Hardee
authors.affiliation: Department of Radiation Oncology, University of Arkansas for Medical Sciences, 4301 W. Markham St., #771, Little Rock, AR 72205.
authors.forename: E Y
authors.initials: EY
authors.lastname: Han
authors.affiliation: Department of Radiation Oncology, University of Arkansas for Medical Sciences, 4301 W. Markham St., #771, Little Rock, AR 72205.
authors.forename: V
authors.initials: V
authors.lastname: Ratanatharathom
mesh_terms: D019583:Dose Fractionation, Radiation; D006801:Humans; D009369:Neoplasms / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D010315:Particle Accelerators; D019047:Phantoms, Imaging; D011880:Radiotherapy Planning, Computer-Assisted; D050397:Radiotherapy, Intensity-Modulated; D036542:Tomography, Spiral Computed; D014584:User-Computer Interface
keywords: Dosimetry; GRID therapy; TOMOGRID template; Tomotherapy.