title: Four-dimensional computed tomography based respiratory-gated radiotherapy with respiratory guidance system: analysis of respiratory signals and dosimetric comparison.
abstract: OBJECTIVE
  To investigate the effectiveness of respiratory guidance system in 4-dimensional computed tomography (4 DCT) based respiratory-gated radiation therapy (RGRT) by comparing respiratory signals and dosimetric analysis of treatment plans.
  
  
  METHODS
  The respiratory amplitude and period of the free, the audio device-guided, and the complex system-guided breathing were evaluated in eleven patients with lung or liver cancers. The dosimetric parameters were assessed by comparing free breathing CT plan and 4 DCT-based 30-70% maximal intensity projection (MIP) plan.
  
  
  RESULTS
  The use of complex system-guided breathing showed significantly less variation in respiratory amplitude and period compared to the free or audio-guided breathing regarding the root mean square errors (RMSE) of full inspiration (P = 0.031), full expiration (P = 0.007), and period (P = 0.007). The dosimetric parameters including V(5 Gy), V(10 Gy), V(20 Gy), V(30 Gy), V(40 Gy), and V(50 Gy) of normal liver or lung in 4 DCT MIP plan were superior over free breathing CT plan.
  
  
  CONCLUSIONS
  The reproducibility and regularity of respiratory amplitude and period were significantly improved with the complex system-guided breathing compared to the free or the audio-guided breathing. In addition, the treatment plan based on the 4D CT-based MIP images acquired with the complex system guided breathing showed better normal tissue sparing than that on the free breathing CT.
authors.affiliation: Department of Radiation Oncology, Korea University College of Medicine, Korea University Medical Center, 126-1 Anamdong 5ga, Seongbukgu, Seoul 136-705, Republic of Korea.
authors.forename: Jung Ae
authors.identifier: 0000-0003-0186-8672
authors.initials: JA
authors.lastname: Lee
authors.affiliation: Department of Radiation Oncology, Korea University College of Medicine, Korea University Medical Center, 126-1 Anamdong 5ga, Seongbukgu, Seoul 136-705, Republic of Korea.
authors.forename: Chul Yong
authors.initials: CY
authors.lastname: Kim
authors.affiliation: Department of Radiation Oncology, Korea University College of Medicine, Korea University Medical Center, 126-1 Anamdong 5ga, Seongbukgu, Seoul 136-705, Republic of Korea.
authors.forename: Dae Sik
authors.initials: DS
authors.lastname: Yang
authors.affiliation: Department of Radiation Oncology, Korea University College of Medicine, Korea University Medical Center, 126-1 Anamdong 5ga, Seongbukgu, Seoul 136-705, Republic of Korea.
authors.forename: Won Sup
authors.initials: WS
authors.lastname: Yoon
authors.affiliation: Department of Radiation Oncology, Korea University College of Medicine, Korea University Medical Center, 126-1 Anamdong 5ga, Seongbukgu, Seoul 136-705, Republic of Korea.
authors.forename: Young Je
authors.initials: YJ
authors.lastname: Park
authors.affiliation: Department of Radiation Oncology, Korea University College of Medicine, Korea University Medical Center, 126-1 Anamdong 5ga, Seongbukgu, Seoul 136-705, Republic of Korea.
authors.forename: Suk
authors.initials: S
authors.lastname: Lee
authors.affiliation: Department of Radiation Oncology, Korea University College of Medicine, Korea University Medical Center, 126-1 Anamdong 5ga, Seongbukgu, Seoul 136-705, Republic of Korea.
authors.forename: Young Bum
authors.initials: YB
authors.lastname: Kim
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D004307:Dose-Response Relationship, Radiation; D005260:Female; D056973:Four-Dimensional Computed Tomography / Q000379:methods*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011878:Radiotherapy; D011879:Radiotherapy Dosage; D012119:Respiration; D055425:Respiratory-Gated Imaging Techniques / Q000379:methods*; D012815:Signal Processing, Computer-Assisted