title: Frequency filtering based analysis on the cardiac induced lung tumor motion and its impact on the radiotherapy management.
abstract: OBJECTIVE
  Lung tumor motion may be impacted by heartbeat in addition to respiration. This study seeks to quantitatively analyze heart-motion-induced tumor motion and to evaluate its impact on lung cancer radiotherapy.
  
  
  METHODS
  Fluoroscopy images were acquired for 30 lung cancer patients. Tumor, diaphragm, and heart were delineated on selected fluoroscopy frames, and their motion was tracked and converted into temporal signals based on deformable registration propagation. The clinical relevance of heart impact was evaluated using the dose volumetric histogram of the redefined target volumes.
  
  
  RESULTS
  Correlation was found between tumor and cardiac motion for 23 patients. The heart-induced motion amplitude ranged from 0.2 to 2.6 mm. The ratio between heart-induced tumor motion and the tumor motion was inversely proportional to the amplitude of overall tumor motion. When the heart motion impact was integrated, there was an average 9% increase in internal target volumes for 17 patients. Dose coverage decrease was observed on redefined planning target volume in simulated SBRT plans.
  
  
  CONCLUSIONS
  The tumor motion of thoracic cancer patients is influenced by both heart and respiratory motion. The cardiac impact is relatively more significant for tumor with less motion, which may lead to clinically significant uncertainty in radiotherapy for some patients.
authors.affiliation: Department of Radiation Oncology, Rutgers Cancer Institute of New Jersey, Rutgers University, New Brunswick, USA. Electronic address: chent4@cinj.rutgers.edu.
authors.forename: Ting
authors.initials: T
authors.lastname: Chen
authors.affiliation: Department of Radiation Oncology, The First Affiliated Hospital of Soochow University, Suzhou, China.
authors.forename: Songbing
authors.initials: S
authors.lastname: Qin
authors.affiliation: Department of Radiation Oncology, The First Affiliated Hospital of Soochow University, Suzhou, China.
authors.forename: Xiaoting
authors.initials: X
authors.lastname: Xu
authors.affiliation: Department of Radiation Oncology, Rutgers Cancer Institute of New Jersey, Rutgers University, New Brunswick, USA.
authors.forename: Salma K
authors.initials: SK
authors.lastname: Jabbour
authors.affiliation: Department of Radiation Oncology, Rutgers Cancer Institute of New Jersey, Rutgers University, New Brunswick, USA.
authors.forename: Bruce G
authors.initials: BG
authors.lastname: Haffty
authors.affiliation: Department of Radiation Oncology, Rutgers Cancer Institute of New Jersey, Rutgers University, New Brunswick, USA.
authors.forename: Ning J
authors.initials: NJ
authors.lastname: Yue
mesh_terms: D005471:Fluoroscopy / Q000379:methods; D056973:Four-Dimensional Computed Tomography / Q000379:methods; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008168:Lung / Q000000981:diagnostic imaging; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000532:radiotherapy*; D009038:Motion; D009200:Myocardial Contraction / Q000502:physiology*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*
keywords: Cardiac motion; Deformable image registration; Fluoroscopy; Frequency analysis; Lung tumor; Respiratory motion