Inter‐ and intrafractional setup errors and baseline shifts of fiducial markers in patients with liver tumors receiving free‐breathing postoperative radiation analyzed by cone‐beam computed tomography

Zhang, Tao; Wang, Weihu; Li, Yexiong; Jin, Jing; Wang, Shulian; Song, Yong-Wen; Liu, Yueping

doi:10.1120/jacmp.v15i6.4914

Cited by 11 publications

(13 citation statements)

References 21 publications

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“…In this study, mean initial setup error was less than 1 cm for all groups which corresponds with previous findings in radiotherapy for pancreas [14] and liver malignancies [15]. There was little difference in initial setup error when comparing compressed patients with uncompressed.…”

Section: Discussionsupporting

confidence: 89%

Impact of abdominal compression on setup error and image matching during radical abdominal radiotherapy

Chu

Cooke

Heuvel

et al. 2019

Technical Innovations & Patient Support in Radiation Oncolo

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To determine the impact of abdominal compression (AC) on setup error and image matching time. Materials and methods: This study included 72 liver, pancreas and abdominal node patients treated radically from 2016 to 2019 in a single centre. Patients received either SBRT or conventional radical fractionation (CRF). Compressed patients were supine, arms up with kneefix and AC equipment. Uncompressed patients were supine, arms up with kneefix. All patients received daily online-matched CBCTs before treatment. Initial setup error was determined for all patients. Registration error was assessed for 10 liver and 10 pancreas patients. Image matching times were determined using beam on times. Statistical tests conducted were an F-test to compare variances in setup error, Student's t-tests for setup error and average image analysis, and a Wilcoxon Mann Whitney test for imaging matching time analysis. Results: Initial setup displacement was similar between compressed and uncompressed patients. Displacements > 1 cm occurred more frequently in the longitudinal direction for most patients. SBRT patients required more additional manual positioning following imaging. Mean absolute registration error in the SI direction was 5.4 mm and 3.3 mm for uncompressed and compressed pancreas patients respectively and 1.7 mm and 0.8 mm for uncompressed and compressed liver patients respectively. Compressed patients required less time for image matching and fewer images per fraction on average. Repeat imaging occurred more frequently in SBRT and uncompressed patients. Conclusions: Although abdominal compression has no significant impact on setup error, it can reduce imaging matching times resulting in improved treatment accuracy.

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Section: Discussionsupporting

confidence: 89%

Impact of abdominal compression on setup error and image matching during radical abdominal radiotherapy

Chu

Cooke

Heuvel

et al. 2019

Technical Innovations & Patient Support in Radiation Oncolo

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“…Absolute target position errors typically consist of patient positioning errors, which are errors in bony structure positioning during setup, and relative target position errors so‐called baseline shifts 3,13 . The aim of this study was to investigate the change in diaphragm position according to physiologic changes such as stomach volume.…”

Section: Methodsmentioning

confidence: 99%

Interfractional diaphragmatic position variation according to stomach volume change during respiratory‐gated radiotherapy for hepatocellular carcinoma

et al. 2021

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Purpose We evaluated the correlation between stomach volume change and interfractional baseline shifts of the diaphragm in image‐guided radiotherapy (IGRT) for hepatocellular carcinoma (HCC). Materials and methods Twenty‐four patients with HCC underwent ten fractions of IGRT, and a total of 240 cone beam computed tomography (CBCT) and on‐board imager (OBI) kV image sets were acquired. These image sets were retrospectively analyzed. Baseline shifts of the diaphragm relative to bone and stomach volume change ratios were evaluated using four‐dimensional simulation CT, kV image, and CBCT images. Associations between baseline shifts and patient physiologic factors were investigated. Results The average baseline shift of the diaphragm in the superior‐inferior (SI) direction was 1.5 mm (standard deviation 4.6 mm), which was higher than the shift in other directions (0.7, 2.0 mm and 0.9, 2.6 mm in right‐left (RL) and anterior‐posterior (AP) directions, respectively). Interfractional baseline shifts of the diaphragm in the SI and AP directions were positively correlated with the stomach volume change ratio (Pearson's r: 0.416 and 0.302, p‐value: <0.001 and <0.001, respectively). Conclusions The interfractional baseline shifts of the diaphragm in the SI and AP directions correlated well with stomach volume changes. Efforts to maintain a constant stomach volume before the simulation and each treatment, such as fasting, may reduce interfractional baseline shifts of liver tumors.

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“…Then, we calculated the IRC as if the patient’s position had not changed during the treatment delivery. In cases with AP patient shifts, both the fiducial locations and the breathing signal were changed accordingly …”

Section: Methodsmentioning

confidence: 99%

Intrafractional relationship changes between an external breathing signal and fiducial marker positions in pancreatic cancer patients

Pettersson

Oderinde

Murphy

et al. 2020

J Applied Clin Med Phys

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Background and purpose The purpose of this study of pancreatic cancer patients treated with respiratory‐guided stereotactic body radiotherapy (SBRT) on a standard linac was to investigate (a) the intrafractional relationship change (IRC) between a breathing signal and the tumor position, (b) the impact of IRC on the delivered dose, and (c) potential IRC predictors. Materials and methods We retrospectively investigated 10 pancreatic cancer patients with 2–4 implanted fiducial markers in the tumor treated with SBRT. Fluoroscopic images were acquired before and after treatment delivery simultaneously with the abdominal breathing motion. We quantified the IRC as the change in fiducial location for a given breathing amplitude in the left–right (LR), anterior–posterior (AP), and superior–inferior (SI) directions from before to after treatment delivery. The treatment plans were re‐calculated after changing the isocenter coordinates according to the IRCs. Four treatment‐ or patient‐related factors were investigated as potential predictors for IRC using linear models. Results The average (±1 SD) absolute IRCs in the LR, AP, and SI directions were 1.2 ± 1.2 mm, 0.7 ± 0.7 mm, and 1.1 ± 0.8 mm, respectively. The average 3D IRC was 2.0 ± 1.3 mm (range: 0.4–5.3 mm) for a median treatment delivery time of 8.5 min (range: 5.7–19.9 min; n = 31 fractions). The dose coverage of the internal target volume (ITV) decreased by more than 3% points in three of 31 fractions. In those cases, the 3D IRC had been larger than 4.3 mm. The 3D IRC was found to correlate with changes in the minimum breathing amplitude during treatment delivery. Conclusion On average, 2 mm of treatment delivery accuracy was lost due to IRC. Periodical intrafractional imaging is needed to safely deliver respiratory‐guided SBRT.

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Inter‐ and intrafractional setup errors and baseline shifts of fiducial markers in patients with liver tumors receiving free‐breathing postoperative radiation analyzed by cone‐beam computed tomography

Cited by 11 publications

References 21 publications

Impact of abdominal compression on setup error and image matching during radical abdominal radiotherapy

Impact of abdominal compression on setup error and image matching during radical abdominal radiotherapy

Interfractional diaphragmatic position variation according to stomach volume change during respiratory‐gated radiotherapy for hepatocellular carcinoma

Intrafractional relationship changes between an external breathing signal and fiducial marker positions in pancreatic cancer patients

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