The advantage of deep-inspiration breath-hold and cone-beam CT based soft-tissue registration for locally advanced lung cancer radiotherapy

• Published in: Radiotherapy and oncology Vol. 119; no. 3; pp. 432 - 437
• Main Authors: Ottosson, Wiviann, Rahma, Fatma, Sjöström, David, Behrens, Claus F, Sibolt, Patrik
• Format: Journal Article
• Language: English
• Published: Ireland Elsevier B.V 01-06-2016
• Subjects: Breath Holding; CBCT imaging; Cone-Beam Computed Tomography - methods; DIBH; Hematology, Oncology and Palliative Medicine; Humans; Lung cancer; Lung Neoplasms - diagnostic imaging; Lung Neoplasms - pathology; Lung Neoplasms - radiotherapy; Margins; Setup methods; Tumor Burden; Uncertainty; Margins; Setup methods; DIBH; CBCT imaging; Lung cancer
• ISSN: 0167-8140; 1879-0887
• DOI: 10.1016/j.radonc.2016.03.012

Abstract Background and purpose Three cone-beam computed tomography (CBCT) registration strategies combined with deep-inspiration breath-hold (DIBH) and free-breathing (FB) were explored, in terms of obtaining the smallest planning target volume (PTV). Material and methods CBCT images were acquired pre- and post-treatment in FB and DIBH, for 17 locally advanced lung cancer patients. Bony registration on the spine, and soft-tissue registrations on the primary gross tumor volume (GTV-T) and GTV-Total, including malignant lymph nodes (GTV-N), were retrospectively analyzed. Setup-margins and resulting PTVs were calculated. Results For the spine, the smallest residual misalignments were observed in FB, independently of registration method. For GTV-T and GTV-N, soft-tissue registrations were superior to bony registration, independently of FB or DIBH. Compared to FB, PTV-Totals were during DIBH reduced by 13% and 8% for the soft-tissue and bony registrations, respectively. If intra-fractional motion was included, the corresponding gain of DIBH was reduced to 9% and 7%, respectively. Superiority of DIBH was mainly due to larger clinical target volumes in FB. Conclusions Despite larger setup uncertainties compared to FB, DIBH resulted in smaller PTV-Totals for all registration methods. Soft-tissue registrations were superior to bony registration, independently of FB and DIBH. During DIBH, undesirable arching of the back was identified. Daily CBCT pre-treatment target verification is advised.