title: Comparison of coplanar and noncoplanar intensity-modulated radiation therapy and helical tomotherapy for hepatocellular carcinoma.
abstract: BACKGROUND
  To compare the differences in dose-volume data among coplanar intensity modulated radiotherapy (IMRT), noncoplanar IMRT, and helical tomotherapy (HT) among patients with hepatocellular carcinoma (HCC) and portal vein thrombosis (PVT).
  
  
  METHODS
  Nine patients with unresectable HCC and PVT underwent step and shoot coplanar IMRT with intent to deliver 46-54 Gy to the tumor and portal vein. The volume of liver received 30Gy was set to keep less than 30% of whole normal liver (V30<30%). The mean dose to at least one side of kidney was kept below 23 Gy, and 50 Gy as for stomach. The maximum dose was kept below 47 Gy for spinal cord. Several parameters including mean hepatic dose, percent volume of normal liver with radiation dose at X Gy (Vx), uniformity index, conformal index, and doses to organs at risk were evaluated from the dose-volume histogram.
  
  
  RESULTS
  HT provided better uniformity for the planning-target volume dose coverage than both IMRT techniques. The noncoplanar IMRT technique reduces the V10 to normal liver with a statistically significant level as compared to HT. The constraints for the liver in the V30 for coplanar IMRT vs. noncoplanar IMRT vs. HT could be reconsidered as 21% vs. 17% vs. 17%, respectively. When delivering 50 Gy and 60-66 Gy to the tumor bed, the constraints of mean dose to the normal liver could be less than 20 Gy and 25 Gy, respectively.
  
  
  CONCLUSIONS
  Noncoplanar IMRT and HT are potential techniques of radiation therapy for HCC patients with PVT. Constraints for the liver in IMRT and HT could be stricter than for 3DCRT.
authors.affiliation: Department of Radiation Oncology, Mackay Memorial Hospital, and Institute of Traditional Medicine, School of Medicine, National Yang-Ming University, Taipei, Taiwan.
authors.forename: Chen-Hsi
authors.initials: CH
authors.lastname: Hsieh
authors.forename: Chia-Yuan
authors.initials: CY
authors.lastname: Liu
authors.forename: Pei-Wei
authors.initials: PW
authors.lastname: Shueng
authors.forename: Ngot-Swan
authors.initials: NS
authors.lastname: Chong
authors.forename: Chih-Jen
authors.initials: CJ
authors.lastname: Chen
authors.forename: Ming-Jen
authors.initials: MJ
authors.lastname: Chen
authors.forename: Ching-Chung
authors.initials: CC
authors.lastname: Lin
authors.forename: Tsang-En
authors.initials: TE
authors.lastname: Wang
authors.forename: Shee-Chan
authors.initials: SC
authors.lastname: Lin
authors.forename: Hung-Chi
authors.initials: HC
authors.lastname: Tai
authors.forename: Hui-Ju
authors.initials: HJ
authors.lastname: Tien
authors.forename: Kuo-Hsin
authors.initials: KH
authors.lastname: Chen
authors.forename: Li-Ying
authors.initials: LY
authors.lastname: Wang
authors.forename: Yen-Ping
authors.initials: YP
authors.lastname: Hsieh
authors.forename: David Y C
authors.initials: DY
authors.lastname: Huang
authors.forename: Yu-Jen
authors.initials: YJ
authors.lastname: Chen
mesh_terms: D006528:Carcinoma, Hepatocellular / Q000473:pathology / Q000532:radiotherapy*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008099:Liver / Q000528:radiation effects; D008175:Lung Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D008297:Male; D011169:Portal Vein / Q000528:radiation effects; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted; D050397:Radiotherapy, Intensity-Modulated; D012189:Retrospective Studies; D015996:Survival Rate; D013927:Thrombosis / Q000473:pathology / Q000532:radiotherapy; D036542:Tomography, Spiral Computed; D016896:Treatment Outcome