Intrafraction target shift comparison using two breath-hold systems in lung stereotactic body radiotherapy. (April 2022)

• Record Type: Journal Article
• Authors: Prado, Alejandro; Zucca, Daniel; De la Casa, Miguel Ángel; Martí, Jaime; Alonso, Leyre; de Acilu, Paz García; García, Juan; Hernando, Ovidio; Fernández-Letón, Pedro; Rubio, Carmen
• Is Part Of: Physics and imaging in radiation oncology. Volume 22(2022)
• Page Start: 57
• Page End: 62
• Publication Date: 2022-04
• Subjects: Stereotactic Body Radiotherapy -- Respiratory motion management -- Deep inspiration breath-hold -- Intrafraction motion estimation -- Surface-guidance system -- Spirometry-based system; Radiotherapy -- Periodicals; Radiation dosimetry -- Periodicals; Cancer -- Imaging -- Periodicals; Oncology -- Periodicals; 615.842
• DOI: 10.1016/j.phro.2022.04.004
• Languages: English
• ISSNs: 2405-6316

Abstract

Highlights: Surface-guided-based and spirometry-based deep-inspiration breath hold were accuracy-equivalent for intrafraction control. Intrafraction shift was reduced when using spirometry-based than surface-guided-based deep-inspiration breath hold. Higher superior-inferior shifts were found for patients with inferior lobe tumors. Systematic and random intrafraction errors were higher for surface-guidance than for spirometry. Abstract: Background and purpose: In lung Stereotactic Body Radiotherapy (SBRT) respiratory management is used to reduce target motion due to respiration. This study aimed (1) to estimate intrafraction shifts through a Cone Beam Computed Tomography (CBCT) acquired during the first treatment arc when deep inspiration breath-hold (DIBH) was performed using spirometry-based (SB) or surface-guidance (SG) systems and (2) to analyze the obtained results depending on lesion localization. Material and methods: A sample of 157 patients with 243 lesions was analyzed. A total of 860 and 410 fractions were treated using SB and SG. Averaged intrafraction shifts were estimated by the offsets obtained when registering a CBCT acquired during the first treatment arc with the planning CT. Offsets were recorded in superior-inferior (SI), left–right (LR) and anterior-posterior (AP). Significance tests were applied to account for differences in average offsets and variances between DIBH systems. Systematic and random errors were computed. Results: Average offset moduli were 2.4 ± 2.2 mm and 3.5 ± 2.6 mm for SB and SG treatments (p < 0.001). When comparing SB and SG offset distributions in each direction no differences were found in average values (p > 0.3). However, variances were statistically smaller for SB than for SG (p < 0.001). The number of vector moduli offsets greater than 5 mm was 2.1 times higher for SG. Compared to other locations, lower lobe lesions moduli were at least 2.3 times higher. Conclusions: Both systems were accuracy-equivalent but not precision-equivalent systems. Furthermore, the SB system was more precise than the SG one. Despite DIBH, patients with lower lobe lesions had larger offsets than superior lobe ones, mainly in SI.