Tim-Oliver Sauer1,2, Oliver J Ott3,4, Godehard Lahmer3,4, Rainer Fietkau3,4, Christoph Bert5,6. 1. Department of Radiation Oncology, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Universitätsstr. 27, 91054, Erlangen, Germany. tim-oliver.sauer@uk-erlangen.de. 2. Comprehensive Cancer Center Erlangen-EMN, Erlangen, Germany. tim-oliver.sauer@uk-erlangen.de. 3. Department of Radiation Oncology, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Universitätsstr. 27, 91054, Erlangen, Germany. 4. Comprehensive Cancer Center Erlangen-EMN, Erlangen, Germany. 5. Department of Radiation Oncology, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Universitätsstr. 27, 91054, Erlangen, Germany. christoph.bert@uk-erlangen.de. 6. Comprehensive Cancer Center Erlangen-EMN, Erlangen, Germany. christoph.bert@uk-erlangen.de.
Abstract
PURPOSE: A markerless workflow for the treatment of breast cancer patients has been introduced and evaluated retrospectively. It includes surface-guided radiation therapy (SGRT)-only positioning for patients with small cone beam CT (CBCT) position corrections during the first five fractions. Prerequisites and the frequency of its clinical application were evaluated, as well as potential benefits in terms of treatment time and dose savings, the frequency of CBCT scans, and the accuracy of the positioning. METHODS: A group of 100 patients treated with the new workflow on two Versa HD linacs has been compared to a matched control group of patients treated with the former workflow, which included prepositioning with skin markings and lasers, SGRT and daily CBCT. The comparison was based on the evaluation of logfiles. RESULTS: Of the patients treated with the new workflow, 40% did not receive daily CBCT scans. This resulted in mean time savings of 97 s, 166 s and 239 s per fraction for the new workflow, for patients treated without daily CBCT and for SGRT-only fractions, respectively, when compared to the old workflow. Dose savings amounted to a weighted computed tomography dose index reduction of CTDIW = 2.56 cGy on average for normofractionated treatment and weekly CBCTs, while for patients not treated with daily CBCT, SGRT-based positioning accuracy was 5.2 mm for the mean translational magnitude, as evaluated by CBCT. CONCLUSION: For 40% of the patients, after five fractions with small CBCT corrections, the workflow could be changed to SGRT-only positioning with weekly CBCT. This leads to imaging dose and time savings and thus also reduced intrafraction motion, potentially increased patient throughput and patient comfort, while assuring appropriate positioning accuracy.
PURPOSE: A markerless workflow for the treatment of breast cancer patients has been introduced and evaluated retrospectively. It includes surface-guided radiation therapy (SGRT)-only positioning for patients with small cone beam CT (CBCT) position corrections during the first five fractions. Prerequisites and the frequency of its clinical application were evaluated, as well as potential benefits in terms of treatment time and dose savings, the frequency of CBCT scans, and the accuracy of the positioning. METHODS: A group of 100 patients treated with the new workflow on two Versa HD linacs has been compared to a matched control group of patients treated with the former workflow, which included prepositioning with skin markings and lasers, SGRT and daily CBCT. The comparison was based on the evaluation of logfiles. RESULTS: Of the patients treated with the new workflow, 40% did not receive daily CBCT scans. This resulted in mean time savings of 97 s, 166 s and 239 s per fraction for the new workflow, for patients treated without daily CBCT and for SGRT-only fractions, respectively, when compared to the old workflow. Dose savings amounted to a weighted computed tomography dose index reduction of CTDIW = 2.56 cGy on average for normofractionated treatment and weekly CBCTs, while for patients not treated with daily CBCT, SGRT-based positioning accuracy was 5.2 mm for the mean translational magnitude, as evaluated by CBCT. CONCLUSION: For 40% of the patients, after five fractions with small CBCT corrections, the workflow could be changed to SGRT-only positioning with weekly CBCT. This leads to imaging dose and time savings and thus also reduced intrafraction motion, potentially increased patient throughput and patient comfort, while assuring appropriate positioning accuracy.
Authors: K J Borm; K Kessel; M Devecka; S Muench; C Straube; K Schiller; L Schüttrumpf; H Dapper; B Wöller; S Pigorsch; S E Combs Journal: Strahlenther Onkol Date: 2019-11-13 Impact factor: 3.621
Authors: Marko Laaksomaa; Sebastian Sarudis; Maija Rossi; Turkka Lehtonen; Jani Pehkonen; Jenny Remes; Helmi Luukkanen; Tanja Skyttä; Mika Kapanen Journal: J Appl Clin Med Phys Date: 2019-03 Impact factor: 2.102
Authors: Rachel B Jimenez; Estelle Batin; Drosoula Giantsoudi; William Hazeltine; Kendell Bertolino; Alice Y Ho; Shannon M MacDonald; Alphonse G Taghian; David P Gierga Journal: J Appl Clin Med Phys Date: 2019-04 Impact factor: 2.102
Authors: Dennis N Stanley; Kristen A McConnell; Neil Kirby; Alonso N Gutiérrez; Nikos Papanikolaou; Karl Rasmussen Journal: J Appl Clin Med Phys Date: 2017-09-13 Impact factor: 2.102