PURPOSE: To investigate the stability of target motion amplitude and motion directionality throughout full stereotactic body radiotherapy (SBRT) treatments of tumors in the liver. MATERIAL AND METHODS: Ten patients with gold markers implanted in the liver received 11 courses of 3-fraction SBRT on a conventional linear accelerator. A four-dimensional computed tomography (4DCT) scan was obtained for treatment planning. The time-resolved marker motion was determined throughout full treatment field delivery using the kV and MV imagers of the accelerator. The motion amplitude and motion directionality of all individual respiratory cycles were determined using principal component analysis (PCA). The variations in motion amplitude and directionality within the treatment courses and the difference from the motion in the 4DCT scan were determined. RESULTS: The patient mean (± 1 standard deviation) peak-to-peak 3D motion amplitude of individual respiratory cycles during a treatment course was 7.9 ± 4.1 mm and its difference from the 4DCT scan was -0.8 ± 2.5 mm (max, 6.6 mm). The mean standard deviation of 3D respiratory cycle amplitude within a treatment course was 2.0 ± 1.6 mm. The motion directionality of individual respiratory cycles on average deviated 4.6 ± 1.6° from the treatment course mean directionality. The treatment course mean motion directionality on average deviated 7.6 ± 6.5° from the directionality in the 4DCT scan. A single patient-specific oblique direction in space explained 97.7 ± 1.7% and 88.3 ± 10.1% of all positional variance (motion) throughout the treatment courses, excluding and including baseline shifts between treatment fields, respectively. CONCLUSION: Due to variable breathing amplitudes a single 4DCT scan was not always representative of the mean motion amplitude during treatment. However, the motion was highly directional with a fairly stable direction throughout treatment, indicating a potential for more optimal individualized motion margins aligned to the preferred direction of motion.
PURPOSE: To investigate the stability of target motion amplitude and motion directionality throughout full stereotactic body radiotherapy (SBRT) treatments of tumors in the liver. MATERIAL AND METHODS: Ten patients with gold markers implanted in the liver received 11 courses of 3-fraction SBRT on a conventional linear accelerator. A four-dimensional computed tomography (4DCT) scan was obtained for treatment planning. The time-resolved marker motion was determined throughout full treatment field delivery using the kV and MV imagers of the accelerator. The motion amplitude and motion directionality of all individual respiratory cycles were determined using principal component analysis (PCA). The variations in motion amplitude and directionality within the treatment courses and the difference from the motion in the 4DCT scan were determined. RESULTS: The patient mean (± 1 standard deviation) peak-to-peak 3D motion amplitude of individual respiratory cycles during a treatment course was 7.9 ± 4.1 mm and its difference from the 4DCT scan was -0.8 ± 2.5 mm (max, 6.6 mm). The mean standard deviation of 3D respiratory cycle amplitude within a treatment course was 2.0 ± 1.6 mm. The motion directionality of individual respiratory cycles on average deviated 4.6 ± 1.6° from the treatment course mean directionality. The treatment course mean motion directionality on average deviated 7.6 ± 6.5° from the directionality in the 4DCT scan. A single patient-specific oblique direction in space explained 97.7 ± 1.7% and 88.3 ± 10.1% of all positional variance (motion) throughout the treatment courses, excluding and including baseline shifts between treatment fields, respectively. CONCLUSION: Due to variable breathing amplitudes a single 4DCT scan was not always representative of the mean motion amplitude during treatment. However, the motion was highly directional with a fairly stable direction throughout treatment, indicating a potential for more optimal individualized motion margins aligned to the preferred direction of motion.
Authors: Patrick Naumann; Vania Batista; Benjamin Farnia; Jann Fischer; Jakob Liermann; Eric Tonndorf-Martini; Bernhard Rhein; Jürgen Debus Journal: Front Oncol Date: 2020-09-25 Impact factor: 6.244
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Authors: Fabian Weykamp; Charlotte Herder-Wagner; Sebastian Regnery; Philipp Hoegen; C Katharina Renkamp; Jakob Liermann; Carolin Rippke; Stefan A Koerber; Laila König; Carolin Buchele; Sebastian Klüter; Jürgen Debus; Juliane Hörner-Rieber Journal: Strahlenther Onkol Date: 2021-09-01 Impact factor: 3.621
Authors: Fabian Weykamp; Philipp Hoegen; Sebastian Klüter; C Katharina Spindeldreier; Laila König; Katharina Seidensaal; Sebastian Regnery; Jakob Liermann; Carolin Rippke; Stefan A Koerber; Carolin Buchele; Jürgen Debus; Juliane Hörner-Rieber Journal: Front Oncol Date: 2021-06-09 Impact factor: 6.244
Authors: Niclas Pettersson; Oluwaseyi M Oderinde; James Murphy; Daniel Simpson; Laura I Cerviño Journal: J Appl Clin Med Phys Date: 2020-03-14 Impact factor: 2.102
Authors: M Mast; E Kouwenhoven; J Roos; S van Geen; J van Egmond; J van Santvoort; L de Boer; M Florijn; Y Kalidien; N Nobel; L Rovers; W van der Togt; S de Vet; N van der Voort van Zyp; F Wenmakers; J van Wingerden; H Ceha Journal: Tech Innov Patient Support Radiat Oncol Date: 2018-05-28