4D‐CT scans reveal reduced magnitude of respiratory liver motion achieved by different abdominal compression plate positions in patients with intrahepatic tumors undergoing helical tomotherapy

Abstract

Purpose: While abdominal compression (AC) can be used to reduce respiratory liver motion in patients receiving helical tomotherapy for hepatocellular carcinoma, the nature and extent of this effect is not well described. The purpose of this study was to evaluate the changes in magnitude of three-dimensional liver motion with abdominal compression using four-dimensional (4D) computed tomography (CT) images of several plate positions. Methods: From January 2012 to October 2015, 72 patients with intrahepatic carcinoma and divided into four groups underwent 4D-CT scans to assess respiratory liver motion. Of the 72 patients, 19 underwent abdominal compression of the cephalic area between the subxiphoid and umbilicus (group A), 16 underwent abdominal compression of the caudal region between the subxiphoid area and the umbilicus (group B), 11 patients underwent abdominal compression of the caudal umbilicus (group C), and 26 patients remained free breathing (group D). 4D-CT images were sorted into ten-image series, according to the respiratory phase from the end inspiration to the end expiration, and then transferred to treatment planning software. All liver contours were drawn by a single physician and confirmed by a second physician. Liver relative coordinates were automatically generated to calculate the liver respiratory motion in different axial directions to compile the 10 ten contours into a single composite image. Differences in respiratory liver motion were assessed with a one-way analysis of variance test of significance. Results: The average respiratory liver motion in the Y axial direction was 4.53 ± 1.16, 7.56 ± 1.30, 9.95 ± 2.32, and 9.53 ± 2.62 mm in groups A, B, C, and D, respectively, with a significant change among the four groups (p < 0.001). Abdominal compression was most effective in group A (compression plate on the subxiphoid area), with liver displacement being 2.53 ± 0.93, 4.53 ± 1.16, and 2.14 ± 0.92 mm on the X-, Y -, and Z-axes, respectively. There was no significant difference in respiratory liver motion between group C (displacement: 3.23 ± 1.47, 9.95 ± 2.32, and 2.92 ± 1.10 mm on the X-, Y -, and Z-axes, respectively) and group D (displacement: 3.35 ± 1.55, 9.53 ± 2.62, and 3.35 ± 1.73 mm on the X-, Y -, and Z-axes, respectively). Abdominal compression was least effective in group C (compression on caudal umbilicus), with liver motion in this group similar to that of free-breathing patients (group D). Conclusions: 4D-CT scans revealed significant liver motion control via abdominal compression of the subxiphoid area; however, this control of liver motion was not observed with compression of the caudal umbilicus. The authors, therefore, recommend compression of the subxiphoid area in patients undergoing external radiotherapy for intrahepatic carcinoma. C 2016 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license

Guidelines for Diagnosis and Treatment of Primary Liver Cancer in China (2017 Edition)

“…Multiple techniques can be used to reduce the impact of respiratory motion, including the gating technique, real-time tracking, breathing control technique, and internal target volume determination based on 4D CT. Abdominal compression is easy to apply and reduces respiratory liver motion. The abdominal compression at the upper segment of the line between the xiphoid process and umbilicus can minimize respiratory liver motion [108]. …”

Magnitude and influencing factors of respiration-induced liver motion during abdominal compression in patients with intrahepatic tumors

“…For example, using 4D-CT, Heinzerling et al [10] demonstrated significantly improved control of liver tumor motion with strong AC compared to medium AC. Likewise, varying AC plate positions may inhibit liver motion to different degrees; the further away from the subxiphoid area the compression is applied, the greater the magnitude of liver motion [2]. In the current study, AC was applied during each patient’s end-expiration until maximum tolerability was reached, as indicated by the patient.…”

“…In order to avoid both inadequate tumor coverage and unnecessary liver parenchyma irradiation, it is crucial to determine the internal target volume (ITV). Abdominal compression (AC) can be used in conjunction with 4-dimensional computed tomography (4D-CT) to reduce liver respiratory motion and determine the ITV [2]. Mid-ventilation is an attractive strategy because it allows smaller planning target volume (PTV) margins to account for breathing motion [3].…”

Experience with an abdominal compression band for radiotherapy of upper abdominal tumours

“…Another reason is the differences in the placement of the compression devices on a patient's abdomen. Hu et al measured the rate of compression at multiple levels within the abdomen to find the position that best provides a reduction in motion of the liver . This study found that the optimal placement of a compression device is in the cephalic area between sub‐xiphoid and umbilicus, with a reduction in the benefit of compression as the compression location moved inferiorly.…”