Serial Megavoltage CT Imaging For Non-Small Cell Lung Cancer: Observations on Tumor Regression During Treatment

Adaptive radiotherapy for locally advanced non-small cell lung cancer, can we predict when and for whom?

“…We observed a signifi cant difference between patients treated with cCRT and sCRT with an average GTV reduction over 30 fractions of 50.1% (1.2%/day) and 33.7% (0.8%/day) respectively. A tumor volume reduction of 1.2% per day is in excellent accordance with previously published results of tumor shrinkage data during cCRT or RT only [10,13]. Our overall volume regression data is also in good agreement with previously published reports using various imaging modalities [10,13,19 -22], as is the signifi cant impact on tumor regression in case of cCRT compared to a sequential scheme [23].…”

Cone beam CT verification for active breathing control (ABC)-gated radiotherapy for lung cancer

“…This is consistent with the literature where reported concerns of tumour deformation and migration affecting image registration accuracy [17,22]. There was no particular ROI which produced better registration between central and peripheral tumours in ABCgated radiotherapy; this compares with non-gated radiotherapy where the Carina was deemed satisfactory for locally advanced tumours [17] and soft tissue matching around the PTV for peripheral tumours [18].…”

Dosimetric impact of respiratory motion, interfraction baseline shifts, and anatomical changes in radiotherapy of non-small cell lung cancer

“…Dose conformation requires accurate knowledge of the patient and target geometry, but this is complicated by anatomical changes and internal tumor motion throughout the treatment course. Anatomical changes include tumor shrinkage [5][6][7] and lung density changes, while the internal tumor motion include interfraction baseline shifts of the mean tumor position [8][9][10] and intrafraction motion due to, i.e. respiration and cardiac motion [11][12][13].…”