To quantify renal and diaphragmatic interfractional motion in order to estimate systematic and random errors, and to investigate the correlation between interfractional motion and patient-specific factors.
We used 527 retrospective abdominal-thoracic cone beam CT scans of 39 childhood cancer patients (<18years) to quantify renal motion relative to bony anatomy in the left-right (LR), cranio-caudal (CC) and anterior-posterior (AP) directions, and diaphragmatic motion in the CC direction only. Interfractional motion was quantified by distributions of systematic and random errors in each direction (standard deviations Σ and σ, respectively). Also, correlation between organ motion and height was analyzed.
Inter-patient organ motion varied widely, with the largest movements in the CC direction. Values of Σ in LR, CC, and AP directions were 1. 1, 3. 8, 2. 1mm for the right, and 1. 3, 3. 0, 1. 5mm for the left kidney, respectively. The σ in these three directions was 1. 1, 3. 1, 1. 7mm for the right, and 1. 2, 2. 9, 2. 1mm for the left kidney, respectively. For the diaphragm we estimated Σ=5. 2mm and σ=4. 0mm. No correlations were found between organ motion and height.
The large inter-patient organ motion variations and the lack of correlation between motion and patient-related factors, suggest that individualized margin approaches might be required.
Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology. 2015 Sep 30 [Epub ahead of print]
Sophie C Huijskens, Irma W E M van Dijk, Rianne de Jong, Jorrit Visser, Raquel Dávila Fajardo, Cécile M Ronckers, Geert O R J Janssens, John H Maduro, Coen R N Rasch, Tanja Alderliesten, Arjan Bel
Academic Medical Center, Department of Radiation Oncology, Amsterdam, The Netherlands. Academic Medical Center, Department of Radiation Oncology, Amsterdam, The Netherlands. , Academic Medical Center, Department of Radiation Oncology, Amsterdam, The Netherlands. , Academic Medical Center, Department of Radiation Oncology, Amsterdam, The Netherlands. , Academic Medical Center, Department of Radiation Oncology, Amsterdam, The Netherlands. , Academic Medical Center/Emma Children's Hospital, Department of Pediatric Oncology, Amsterdam, The Netherlands. , Radboud University Medical Center, Department of Radiation Oncology, Nijmegen, The Netherlands. , University of Groningen, Department of Radiation Oncology, The Netherlands. , Academic Medical Center, Department of Radiation Oncology, Amsterdam, The Netherlands. , Academic Medical Center, Department of Radiation Oncology, Amsterdam, The Netherlands. , Academic Medical Center, Department of Radiation Oncology, Amsterdam, The Netherlands.