title: Magnitude of shift of tumor position as a function of moderated deep inspiration breath-hold: An analysis of pooled data of lung patients with active breath control in image-guided radiotherapy.
abstract: The purpose of this study was to evaluate the reproducibility and magnitude of shift of tumor position by using active breathing control and iView-GT for patients with lung cancer with moderate deep-inspiration breath-hold (mDIBH) technique. Eight patients with 10 lung tumors were studied. CT scans were performed in the breath-holding phase. Moderate deep-inspiration breath-hold under spirometer-based monitoring system was used. Few important bony anatomic details were delineated by the radiation oncologist. To evaluate the interbreath-hold reproducibility of the tumor position, we compared the digital reconstruction radiographs (DRRs) from planning system with the DRRs from the iView-GT in the machine room. We measured the shift in x, y, and z directions. The reproducibility was defined as the difference between the bony landmarks from the DRR of the planning system and those from the DRR of the iView-GT. The maximum shift of the tumor position was 3.2 mm, 3.0 mm, and 2.9 mm in the longitudinal, lateral, and vertical directions. In conclusion, the moderated deep-inspiration breath-hold method using a spirometer is feasible, with relatively good reproducibility of the tumor position for image-guided radiotherapy in lung cancers.
authors.affiliation: Indo-American Cancer Institute and Research Center, Hyderabad, AP, India.
authors.forename: K R
authors.initials: KR
authors.lastname: Muralidhar
authors.forename: P Narayana
authors.initials: PN
authors.lastname: Murthy
authors.forename: D Shankar
authors.initials: DS
authors.lastname: Mahadev
authors.forename: K
authors.initials: K
authors.lastname: Subramanyam
authors.forename: G
authors.initials: G
authors.lastname: Sudarshan
authors.forename: A Krishnam
authors.initials: AK
authors.lastname: Raju