Segmental analysis of respiratory liver motion in patients with and without a history of abdominal surgery

Shimizu, Yasuhiro; Takamatsu, Shigeyuki; Yamamoto, Kazutaka; Maeda, Yoshikazu; Sasaki, Makoto; Tamamura, Hiroyasu; Bou, Sayuri; Kumano, Tomoyasu; Gabata, Toshifumi

doi:10.1007/s11604-018-0750-3

Cited by 7 publications

(6 citation statements)

References 30 publications

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“…For example, Dawson et al reported the diaphragm position correlates within approximately 0.2 cm with microcoils implanted near hepatic tumors and that the diaphragm likely correlates well with liver tumors [ 26 ]. Furthermore, Shimizu et al found that the extents of respiratory movements of the liver varies depending on the segment and that surgery suppresses respiratory movements [ 27 ]. Therefore, it is important to confirm the movement using 4DCT and set the ITV margin in each case and individual lesion.…”

Section: Discussionmentioning

confidence: 99%

Long-Term Results of Proton Therapy for Hepatocellular Carcinoma Using Four-Dimensional Computed Tomography Planning without Fiducial Markers

Bou

Takamatsu

Matsumoto

et al. 2022

Cancers

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We report here the long-term results of marker-less respiratory-gated proton therapy (PT), without fiducial markers for hepatocellular carcinoma (HCC), which was planned using a four-dimensional computed tomography technique. Local tumor control (LTC) and overall survival (OS) were estimated using the Kaplan–Meier method. Toxicity was graded per CTCAE v5.0. Patients (n = 105; median age 73 years, range 38–90 years) with 128 lesions were treated. The median radiation dose was 66 gray relative biological effectiveness (GyRBE) (range, 52.8–82.5 GyRBE) delivered in 2.0 to 6.6 GyRBE fractions, depending on lesion volume, the involved liver, and the patient’s condition. The median follow-up of surviving patients was 63 months (range, 1–126 months), and the 5-year LTC and OS rates were 93.2% and 40.4%, respectively. Univariate and multivariate analyses identified tumors near the gastrointestinal tract as an independent risk factor for local recurrence and revealed that hepatic reserve, tumor stage, performance status, operability, sex, and portal vein thrombosis were independent risk factors for OS. Acute and late treatment-related grade 3 toxicities were experienced by eight patients (7.6%). Adverse events ≥ grade 4 were not evident. Marker-less respiratory-gated PT for HCC is a safe and effective treatment without severe complications.

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Section: Discussionmentioning

confidence: 99%

Long-Term Results of Proton Therapy for Hepatocellular Carcinoma Using Four-Dimensional Computed Tomography Planning without Fiducial Markers

Bou

Takamatsu

Matsumoto

et al. 2022

Cancers

Self Cite

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“…The patient setup and the planning imaging have been described. 5 Briefly, the sCT images were acquired by respiratory-synchronized 4D CT (Aquilion LB; Canon Medical Systems, Tochigi, Japan) in combination with the breathing synchronization method in which the updown respiratory motion of the abdominal wall was monitored in real time by the laser sensor equipped with a respiratory gating system (AZ-733 V; Anzai Medical Co., Tokyo). The sCT for treatment planning was reconstructed at the end of an expiration phase with a 500-ms window where the wave signal showed the minimum value.…”

Section: Management Of the Patients' Immobilization And Respiratory M...mentioning

confidence: 99%

“…During the entire treatment, inter-fractional anatomical changes as well as changes in the patient's respiratory condition cause the tumor location to vary inside the liver, and respiratory motion shows variation among liver segments. 5 These variations affect the water equivalent length (WEL) along the proton beam directions from the skin surface to the distal side of the tumor, which may cause protons to stop at a depth that is different from the depth predicted by the treatment plan. A daily placement of the radiation beam with respect to the tumor inside the liver is thus important to take advantage of the physical selectivity of proton therapy.…”

Section: Introductionmentioning

confidence: 99%

Effectiveness of CT‐image guidance in proton therapy for liver cancer and the importance of daily dose monitoring for tumors and organs at risk

et al. 2023

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Background: It is important to have precise image guidance throughout proton therapy in order to take advantage of the therapy's physical selectivity. Purpose: We evaluated the effectiveness of computed tomography (CT)-image guidance in proton therapy for patients with hepatocellular carcinoma (HCC) by assessing daily proton dose distributions. The importance of daily CT imageguided registration and daily proton dose monitoring for tumors and organs at risk (OARs) was investigated. Methods: A retrospective analysis was conducted using 570 sets of daily CT (dCT) images throughout whole treatment fractions for 38 HCC patients who underwent passive scattering proton therapy with either a 66 cobalt gray equivalent (GyE)/10 fractions (n = 19) or 76 GyE/20 fractions (n = 19) protocol. The actual daily delivered dose distributions were estimated by forward calculation using the dCT sets, their corresponding treatment plans, and the recorded daily couch correction information. We then evaluated the daily changes of the dose indices D 99% , V 30GyE , and D max for the tumor volumes, non-tumorous liver, and other OARs, that is, stomach, esophagus, duodenum, colon, respectively. Contours were created for all dCT sets. We validated the efficacy of the dCT-based tumor registrations (hereafter, "tumor registration") by comparing them with the bone registration and diaphragm registration as a simulation of the treatment based on the positioning using the conventional kV X-ray imaging. The dose distributions and the indices of three registrations were obtained by simulation using the same dCT sets. Results: In the 66 GyE/10 fractions, the daily D 99% value in both the tumor and diaphragm registrations agreed with the planned value with 3%-6% (SD), and the V 30GyE value for the liver agreed within ±3%; the indices in the bone registration showed greater deterioration. Nevertheless, tumor-dose deterioration occurred in all registration methods for two cases due to daily changes of body shape and respiratory condition. In the 76 GyE/20 fractions, in particular for such a treatment that the dose constraints for the OARs have to be cared in the original planning, the daily D 99% in the tumor registration was superior to that in the other registration (p < 0.001), indicating the effectiveness of the tumor registration. The dose constraints, set in the plan as the maximum dose for OARs (i.e., duodenum, stomach, colon, and esophagus) were maintained for 16 patients including seven treated with re-planning. For three patients, the daily 3274

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“…First, the liver grayscale patterns in CT images are very similar to those of the surrounding organs (such as the stomach, pancreas, kidneys, and muscles) (7)(8)(9). Secondly, liver shapes and sizes vary widely across patients (10,11). Thirdly, differences in CT scanning equipment lead to large variations in CT image appearance and liver location (12,13).…”

Section: Original Articlementioning

confidence: 99%

Liver segmentation in CT imaging with enhanced mask region-based convolutional neural networks

Chen¹,

Wei²,

Tang³

et al. 2021

Ann Transl Med

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Background: Liver segmentation in computed tomography (CT) imaging has been widely investigated as a crucial step for analyzing liver characteristics and diagnosing liver diseases. However, obtaining satisfactory liver segmentation performance is highly challenging because of the poor contrast between the liver and its surrounding organs and tissues, the high levels of CT image noise, and the wide variability in liver shapes among patients.Methods: To overcome these challenges, we propose a novel method for liver segmentation in CT image sequences. This method uses an enhanced mask region-based convolutional neural network (Mask R-CNN) with graph-cut segmentation. Specifically, the k-nearest neighbor (k-NN) algorithm is employed to cluster the target liver pixels in order to get an appropriate aspect ratio. Then, anchors are adapted to the liver size using the ratio information. Thus, high-accuracy liver localization can be achieved using the anchors and rotation-invariant object recognition. Next, a fully convolutional network (FCN) is used to segment the foreground objects, and local fine-grained liver detection is realized by pixel prediction. Finally, a whole liver mask is obtained by Mask R-CNN proposed in this paper.Results: We proposed a Mask R-CNN algorithm which achieved superior performance in comparison with the conventional Mask R-CNN algorithms in term of the dice similarity coefficient (DSC), and the Medical Image Computing and Computer-Assisted Intervention (MICCAI) metrics.Conclusions: Our experimental results demonstrate that the improved Mask R-CNN architecture has good performance, accuracy, and robustness for liver segmentation in CT image sequences.

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Segmental analysis of respiratory liver motion in patients with and without a history of abdominal surgery

Abstract: The distances and directions of respiratory motion differed for each liver segment, and a history of abdominal surgery reduced the respiratory motion of the liver. It is necessary to selectively use the internal margin setting.

Cited by 7 publications

References 30 publications

Long-Term Results of Proton Therapy for Hepatocellular Carcinoma Using Four-Dimensional Computed Tomography Planning without Fiducial Markers

Long-Term Results of Proton Therapy for Hepatocellular Carcinoma Using Four-Dimensional Computed Tomography Planning without Fiducial Markers

Effectiveness of CT‐image guidance in proton therapy for liver cancer and the importance of daily dose monitoring for tumors and organs at risk

Liver segmentation in CT imaging with enhanced mask region-based convolutional neural networks

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