title: Risk of second cancer from scattered radiation of intensity-modulated radiotherapies with lung cancer.
abstract: OBJECTIVE
  To compare the risk of secondary cancer from scattered and leakage doses following intensity-modulated radiotherapy (IMRT), volumetric arc therapy (VMAT) and tomotherapy (TOMO) in patients with lung cancer.
  
  
  METHODS
  IMRT, VMAT and TOMO were planned for five lung cancer patients. Organ equivalent doses (OEDs) are estimated from the measured corresponding secondary doses during irradiation at various points 20 to 80 cm from the iso-center by using radio-photoluminescence glass dosimeter (RPLGD).
  
  
  RESULTS
  The secondary dose per Gy from IMRT, VMAT and TOMO for lung cancer, measured 20 to 80 cm from the iso-center, are 0.02~2.03, 0.03~1.35 and 0.04~0.46 cGy, respectively. The mean values of relative OED of secondary dose of VMAT and TOMO, which is normalized by IMRT, ranged between 88.63% and 41.59% revealing 88.63% and 41.59% for thyroid, 82.33% and 41.85% for pancreas, 77.97% and 49.41% for bowel, 73.42% and 72.55% for rectum, 74.16% and 81.51% for prostate. The secondary dose and OED from TOMO became similar to those from IMRT and VMAT as the distance from the field edge increased.
  
  
  CONCLUSIONS
  OED based estimation suggests that the secondary cancer risk from TOMO is less than or comparable to the risks from conventional IMRT and VMAT.
authors: Department of Radiation Oncology, Kyung Hee University Hospital at Gangdong, Seoul, Korea.
authors: Dong Wook
authors: DW
authors: Kim
authors: Weon Kuu
authors: WK
authors: Chung
authors: Dongoh
authors: D
authors: Shin
authors: Seongeon
authors: S
authors: Hong
authors: Sung Ho
authors: SH
authors: Park
authors: Sung-Yong
authors: SY
authors: Park
authors: Kwangzoo
authors: K
authors: Chung
authors: Young Kyung
authors: YK
authors: Lim
authors: Dongho
authors: D
authors: Shin
authors: Se Byeong
authors: SB
authors: Lee
authors: Hyun-Ho
authors: HH
authors: Lee
authors: Myonggeun
authors: M
authors: Yoon
mesh_terms: D000368:Aged; D000465:Algorithms; D002289:Carcinoma, Non-Small-Cell Lung / Q000150:complications / Q000473:pathology / Q000532:radiotherapy; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008175:Lung Neoplasms / Q000150:complications / Q000473:pathology / Q000532:radiotherapy*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D009381:Neoplasms, Radiation-Induced / Q000175:diagnosis / Q000209:etiology*; D016609:Neoplasms, Second Primary / Q000175:diagnosis / Q000209:etiology*; D058958:Organs at Risk / Q000528:radiation effects; D011379:Prognosis; D011879:Radiotherapy Dosage; D050397:Radiotherapy, Intensity-Modulated / Q000009:adverse effects*; D012307:Risk Factors; D012542:Scattering, Radiation