title: Kilovoltage Imaging of Implanted Fiducials to Monitor Intrafraction Motion With Abdominal Compression During Stereotactic Body Radiation Therapy for Gastrointestinal Tumors.
abstract: To assess intrafraction respiratory motion using a commercial kilovoltage imaging system for abdominal tumor patients with implanted fiducials and breathing constrained by pneumatic compression during stereotactic body radiation therapy (SBRT).
  
  
  
  A pneumatic compression belt limited respiratory motion in 19 patients with radiopaque fiducials in or near their tumor during SBRT for abdominal tumors. Kilovoltage images were acquired at 5- to 6-second intervals during treatment using a commercial system. Intrafractional fiducial displacements were measured using in-house software. The dosimetric effect of the observed displacements was calculated for 3 sessions for each patient.
  
  
  
  Intrafraction displacement patterns varied between patients and between individual treatment sessions. Averaged over 19 patients, 73 sessions, 7.6% of craniocaudal displacements exceeded 0.5 cm, and 1.2% exceeded 0.75 cm. The calculated single-session dose to 95% of gross tumor volume differed from planned by an average of -1.2% (range, -11.1% to 4.8%) but only for 4 patients was the total 3-session calculated dose to 95% of gross tumor volume more than 3% different from planned.
  
  
  
  Our pneumatic compression limited intrafractional abdominal target motion, maintained target position established at setup, and was moderately effective in preserving coverage. Commercially available intrafractional imaging is useful for surveillance but can be made more effective and reliable.
authors.affiliation: Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, New York. Electronic address: yorke@mskcc.org.
authors.forename: Ellen
authors.initials: E
authors.lastname: Yorke
authors.affiliation: Department of Radiation Oncology, China-Japan Friendship Hospital, Beijing, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Xiong
authors.affiliation: Department of Radiotherapy, Henan Provincial People's Hospital, Zhengzhou, China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Han
authors.affiliation: Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, New York.
authors.forename: Pengpeng
authors.initials: P
authors.lastname: Zhang
authors.affiliation: Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, New York.
authors.forename: Gikas
authors.initials: G
authors.lastname: Mageras
authors.affiliation: Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, New York.
authors.forename: Michael
authors.initials: M
authors.lastname: Lovelock
authors.affiliation: Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, New York.
authors.forename: Hai
authors.initials: H
authors.lastname: Pham
authors.affiliation: Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, New York.
authors.forename: Jian-Ping
authors.initials: JP
authors.lastname: Xiong
authors.affiliation: Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, New York.
authors.forename: Karyn A
authors.initials: KA
authors.lastname: Goodman
mesh_terms: D000005:Abdomen; D000008:Abdominal Neoplasms / Q000000981:diagnostic imaging / Q000532:radiotherapy; D000368:Aged; D016477:Artifacts; D019583:Dose Fractionation, Radiation; D005260:Female; D057918:Fiducial Markers; D005770:Gastrointestinal Neoplasms / Q000000981:diagnostic imaging* / Q000532:radiotherapy*; D006801:Humans; D007103:Immobilization / Q000295:instrumentation / Q000379:methods*; D048228:Intermittent Pneumatic Compression Devices; D008297:Male; D008875:Middle Aged; D009038:Motion; D016634:Radiosurgery / Q000295:instrumentation / Q000379:methods*; D011879:Radiotherapy Dosage; D061089:Radiotherapy, Image-Guided / Q000295:instrumentation / Q000379:methods*; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods; D016896:Treatment Outcome