title: Respiratory correlated segment reconstruction algorithm towards four-dimensional radiation therapy using carbon ion beams.
abstract: OBJECTIVE
  To enhance the precision of treatment planning for tumors which move under respiration, we developed a respiratory-correlated segment reconstruction method (RS) based on the Feldkamp--Davis--Kress algorithm (FDK) which provides high temporal resolution and a high signal-to-noise ratio. We compared full-scan (FS-FDK) and RS-FDK with regard to dose distribution in heavy ion treatment planning.
  
  
  METHODS
  Data acquisition for RS-FDK is done using a respiratory sensing system in cine scan mode with a 256-multi-detector row CT (256-MDCT). To evaluate the accuracy of irradiation of moving tumors, dose distributions with each algorithm were compared in heavy ion treatment planning using beam parameters obtained with FS-FDK.
  
  
  RESULTS
  Images obtained using RS-FDK did not show motion artifacts and visualized the edges of the liver and pulmonary vessels more clearly than those with FS-FDK. The iso-dose distributions for FS-FDK covered the target volume; in contrast, RS-FDK with the beam parameter of FS-FDK image provided an insufficient dose to the target and a considerable dose to normal tissues around it.
  
  
  CONCLUSIONS
  The information provided by RS-FDK improves accuracy in the prescription of dose-to-target volume. Further, RS-FDK allows greater precision in the delivery of radiotherapy, including 4D radiation therapy.
authors.affiliation: Radiological Protection Section, National Institute of Radiological Sciences, Chiba-shi, Chiba, Japan. smori1@partners.org
authors.forename: Shinichiro
authors.initials: S
authors.lastname: Mori
authors.forename: Masahiro
authors.initials: M
authors.lastname: Endo
authors.forename: Ryosuke
authors.initials: R
authors.lastname: Kohno
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Asakura
authors.forename: Kazutoshi
authors.initials: K
authors.lastname: Kohno
authors.forename: Tomoyasu
authors.initials: T
authors.lastname: Yashiro
authors.forename: Shuhei
authors.initials: S
authors.lastname: Komatsu
authors.forename: Susumu
authors.initials: S
authors.lastname: Kandatsu
authors.forename: Masayuki
authors.initials: M
authors.lastname: Baba
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D002250:Carbon Radioisotopes / Q000627:therapeutic use*; D006801:Humans; D008297:Male; D019047:Phantoms, Imaging; D011857:Radiographic Image Interpretation, Computer-Assisted; D012119:Respiration; D014057:Tomography, X-Ray Computed / Q000295:instrumentation / Q000379:methods* / Q000592:standards
chemical_list: D002250:Carbon Radioisotopes