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Updated: May 6, 2026
Dynamic Lung Tumor Tracking for Stereotactic Ablative Body Radiation Therapy
Published on: June 7, 2015
Reproducibility of target coverage in stereotactic spot scanning proton lung irradiation under high frequency jet
Alina Santiago1, Urszula Jelen, Filippo Ammazzalorso
1University of Marburg, Department of Radiotherapy and Radiation Oncology, Germany.
Purpose:
To investigate scanned-beam proton dose distribution reproducibility in the lung under high frequency jet ventilation (HFJV).
Materials And Methods:
For 11 patients (12 lesions), treated with single-fraction photon stereotactic radiosurgery under HFJV, scanned-beam proton plans were prepared with the TRiP98 treatment planning system using 2, 3-4 and 5-7 beams. The planning objective was to deliver at least 95% of the prescription of 33 Gy (RBE) to 98% of the PTV. Plans were subsequently recomputed on localization CT scans. Additionally, for selected cases, the effects of range uncertainties were investigated.
Results:
Median GTV V(98%) was 98.7% in the original 2-field plans and 93.7% in their recomputation (p=0.039). The respective values were 99.0% and 98.0% (p=0.039) for the 3-4-field plans and 100.0% and 99.6% (p=0.125) for the 5-7-field plans. CT calibration uncertainties of ±3.5% led to a GTV V(98%) reduction below 1.5 percentual points in most cases and reaching 3 percentual points for 2-field plans with beam undershoot.
Conclusions:
Through jet ventilation, reproducible tumor fixation for proton radiotherapy of lung lesions is achievable, ensuring excellent target coverage in most cases. In few cases, non-optimal patient setup reproducibility induced density changes across beam entrance channels, leading to dosimetric deterioration between planning and delivery.
