OBJECTIVE: The aim of this study was to evaluate interfraction uncertainties using kilovoltage (kV) radiographs for patients with gastric cancer during chemoradiotherapy and to calculate the planning target volume (PTV) margins. METHODS: 1284 measurements of set-up errors were analysed for treated patients. The measurements of craniocaudal (axis y), laterolateral (axis x) and anteroposterior (axis z) shifts in kV radiographs were performed. Interfraction clinical target volume (CTV)-PTV margins for all directions were calculated using the van Herk formula. RESULTS: The main shift for the y-axis was 0.7 mm [standard deviation (SD), ±7.6], for the x-axis was 0.4 mm (SD, ±3.7) and for the z-axis was 0.6 mm (SD, ±3.5). The CTV-PTV margin in the x, y and z directions was 8.3, 15.5 and 8.0 mm, respectively. We observed that the interfractional motion for patients increased approximately 0.0034 cm along the x direction with each subsequent fraction, whereas a 0.0058-cm reduction in length along the y-axis was observed. No time effects for the z direction were noticed. CONCLUSION: According to our experience, a PTV margin of 9 mm along the x-axis, 16 mm along the y-axis and 8 mm along the z direction should be considered in the absence of image-guided radiotherapy. ADVANCES IN KNOWLEDGE: This knowledge concerning PTV set-up margins could be particularly useful for centres without a kV on-board imaging system.
OBJECTIVE: The aim of this study was to evaluate interfraction uncertainties using kilovoltage (kV) radiographs for patients with gastric cancer during chemoradiotherapy and to calculate the planning target volume (PTV) margins. METHODS: 1284 measurements of set-up errors were analysed for treated patients. The measurements of craniocaudal (axis y), laterolateral (axis x) and anteroposterior (axis z) shifts in kV radiographs were performed. Interfraction clinical target volume (CTV)-PTV margins for all directions were calculated using the van Herk formula. RESULTS: The main shift for the y-axis was 0.7 mm [standard deviation (SD), ±7.6], for the x-axis was 0.4 mm (SD, ±3.7) and for the z-axis was 0.6 mm (SD, ±3.5). The CTV-PTV margin in the x, y and z directions was 8.3, 15.5 and 8.0 mm, respectively. We observed that the interfractional motion for patients increased approximately 0.0034 cm along the x direction with each subsequent fraction, whereas a 0.0058-cm reduction in length along the y-axis was observed. No time effects for the z direction were noticed. CONCLUSION: According to our experience, a PTV margin of 9 mm along the x-axis, 16 mm along the y-axis and 8 mm along the z direction should be considered in the absence of image-guided radiotherapy. ADVANCES IN KNOWLEDGE: This knowledge concerning PTV set-up margins could be particularly useful for centres without a kV on-board imaging system.
Authors: Barbara Wysocka; Zahra Kassam; Gina Lockwood; James Brierley; Laura A Dawson; Carol Ann Buckley; David Jaffray; Bernard Cummings; John Kim; Rebecca Wong; Jolie Ringash Journal: Int J Radiat Oncol Biol Phys Date: 2009-08-06 Impact factor: 7.038
Authors: Maria A Hawkins; Alexandra Aitken; Vibeke N Hansen; Helen A McNair; Diana M Tait Journal: Radiother Oncol Date: 2010-12-06 Impact factor: 6.280
Authors: Priya Jayachandran; A Yuriko Minn; Jacques Van Dam; Jeffrey A Norton; Albert C Koong; Daniel T Chang Journal: Int J Radiat Oncol Biol Phys Date: 2009-10-30 Impact factor: 7.038
Authors: Oscar Matzinger; Erich Gerber; Zvi Bernstein; Philippe Maingon; Karin Haustermans; Jean François Bosset; Akos Gulyban; Philip Poortmans; Laurence Collette; Abraham Kuten Journal: Radiother Oncol Date: 2009-04-15 Impact factor: 6.280
Authors: Paulina Leszczyńska; Wojciech Leszczyński; Jerzy Wydmański; Agnieszka Namysł Kaletka; Andrzej Tukiendorf; Leszek Hawrylewicz Journal: Asian Pac J Cancer Prev Date: 2017-01-01