Target position uncertainty during visually guided deep-inspiration breath-hold radiotherapy in locally advanced lung cancer

• Published in: Radiotherapy and oncology 2017-04, Vol.123 (1), p.78-84
• Main Authors: Scherman Rydhög, Jonas, Riisgaard de Blanck, Steen, Josipovic, Mirjana, Irming Jølck, Rasmus, Larsen, Klaus Richter, Clementsen, Paul, Lars Andersen, Thomas, Poulsen, Per Rugaard, Fredberg Persson, Gitte, Munck af Rosenschold, Per
• Format: Article
• Language: English
• Subjects: Breath Holding; Carcinoma, Non-Small-Cell Lung - radiotherapy; Female; Fluoroscopy; Hematology, Oncology and Palliative Medicine; Humans; Image based tracking; Image-guided radiotherapy; Liquid fiducial marker; Lung Neoplasms - radiotherapy; Male; Uncertainty
• ISSN: 0167-8140; 1879-0887
• DOI: 10.1016/j.radonc.2017.02.003

Abstract Purpose The purpose of this study was to estimate the uncertainty in voluntary deep-inspiration breath-hold (DIBH) radiotherapy for locally advanced non-small cell lung cancer (NSCLC) patients. Methods Perpendicular fluoroscopic movies were acquired in free breathing (FB) and DIBH during a course of visually guided DIBH radiotherapy of nine patients with NSCLC. Patients had liquid markers injected in mediastinal lymph nodes and primary tumours. Excursion, systematic- and random errors, and inter-breath-hold position uncertainty were investigated using an image based tracking algorithm. Results A mean reduction of 2–6 mm in marker excursion in DIBH versus FB was seen in the anterior-posterior (AP), left–right (LR) and cranio-caudal (CC) directions. Lymph node motion during DIBH originated from cardiac motion. The systematic- (standard deviation (SD) of all the mean marker positions) and random errors (root-mean-square of the intra-BH SD) during DIBH were 0.5 and 0.3 mm (AP), 0.5 and 0.3 mm (LR), 0.8 and 0.4 mm (CC), respectively. The mean inter-breath-hold shifts were −0.3 mm (AP), −0.2 mm (LR), and −0.2 mm (CC). Conclusion Intra- and inter-breath-hold uncertainty of tumours and lymph nodes were small in visually guided breath-hold radiotherapy of NSCLC. Target motion could be substantially reduced, but not eliminated, using visually guided DIBH.