Colien Hazelaar1, Max Dahele2, Stefan Scheib3, Ben J Slotman2, Wilko F A R Verbakel2. 1. Department of Radiation Oncology, VU University Medical Center, Amsterdam, The Netherlands. Electronic address: c.hazelaar@vumc.nl. 2. Department of Radiation Oncology, VU University Medical Center, Amsterdam, The Netherlands. 3. Varian Medical Systems Imaging Laboratory GmbH, Switzerland.
Abstract
BACKGROUND AND PURPOSE: Proof of tumor position during stereotactic body radiotherapy (SBRT) delivery is desirable. We investigated if cone-beam CT (CBCT) scans reconstructed from (collimated) fluoroscopic kV images acquired during irradiation could show the dominant tumor position. MATERIALS AND METHODS: Full-arc CBCT scans were reconstructed using FDK filtered back projection from 38kV fluoroscopy datasets (16 patients) continuously acquired during volumetric modulated spine SBRT. CBCT-CT match values were compared to the average spine offset values found using template matching+triangulation of the individual kV images. Multiple limited-arc CBCTs were reconstructed from fluoroscopic images acquired during lung SBRT of an anthropomorphic thorax phantom using 20-180° arc lengths and for 3 breath-hold lung SBRT patients. RESULTS: Differences between 3D CBCT-CT match results and average spine offsets found using template matching+triangulation were 0.1±0.1mm for all directions (range: 0.0-0.5mm). For limited-arc CBCTs of the thorax phantom, the automatic 3D CBCT-CT match results for arc lengths of 80-180° were ≤1mm. 20° CBCT reconstruction still allowed for positional verification in 2D. CONCLUSIONS: (Limited-arc) CBCT reconstructions of kV images acquired during irradiation can identify the dominant position of the tumor during treatment delivery.
BACKGROUND AND PURPOSE: Proof of tumor position during stereotactic body radiotherapy (SBRT) delivery is desirable. We investigated if cone-beam CT (CBCT) scans reconstructed from (collimated) fluoroscopic kV images acquired during irradiation could show the dominant tumor position. MATERIALS AND METHODS: Full-arc CBCT scans were reconstructed using FDK filtered back projection from 38kV fluoroscopy datasets (16 patients) continuously acquired during volumetric modulated spine SBRT. CBCT-CT match values were compared to the average spine offset values found using template matching+triangulation of the individual kV images. Multiple limited-arc CBCTs were reconstructed from fluoroscopic images acquired during lung SBRT of an anthropomorphic thorax phantom using 20-180° arc lengths and for 3 breath-hold lung SBRT patients. RESULTS: Differences between 3D CBCT-CT match results and average spine offsets found using template matching+triangulation were 0.1±0.1mm for all directions (range: 0.0-0.5mm). For limited-arc CBCTs of the thorax phantom, the automatic 3D CBCT-CT match results for arc lengths of 80-180° were ≤1mm. 20° CBCT reconstruction still allowed for positional verification in 2D. CONCLUSIONS: (Limited-arc) CBCT reconstructions of kV images acquired during irradiation can identify the dominant position of the tumor during treatment delivery.
Authors: Christos Moustakis; Mark K H Chan; Jinkoo Kim; Joakim Nilsson; Alanah Bergman; Tewfik J Bichay; Isabel Palazon Cano; Savino Cilla; Francesco Deodato; Raffaela Doro; Jürgen Dunst; Hans Theodor Eich; Pierre Fau; Ming Fong; Uwe Haverkamp; Simon Heinze; Guido Hildebrandt; Detlef Imhoff; Erik de Klerck; Janett Köhn; Ulrike Lambrecht; Britta Loutfi-Krauss; Fatemeh Ebrahimi; Laura Masi; Alan H Mayville; Ante Mestrovic; Maaike Milder; Alessio G Morganti; Dirk Rades; Ulla Ramm; Claus Rödel; Frank-Andre Siebert; Wilhelm den Toom; Lei Wang; Stefan Wurster; Achim Schweikard; Scott G Soltys; Samuel Ryu; Oliver Blanck Journal: Strahlenther Onkol Date: 2018-05-25 Impact factor: 3.621
Authors: Alejandro Prado; Daniel Zucca; Miguel Ángel De la Casa; Jaime Martí; Leyre Alonso; Paz García de Acilu; Juan García; Ovidio Hernando; Pedro Fernández-Letón; Carmen Rubio Journal: Phys Imaging Radiat Oncol Date: 2022-04-29