Respiratory motion of lymph node stations in pancreatic cancer: Analyses using contrast-enhanced four-dimensional computed tomography

Takahashi, Shojiro; Anada, Masahide; Kinoshita, Toshiro; Shibata, Toru

doi:10.1016/j.radonc.2018.05.007

Cited by 4 publications

(5 citation statements)

References 22 publications

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“…Thus, in this study, we used the diagnostic protocol for acquiring CT images to plan the weight-equivalent contrast agent doses. Because the body weight range and mean weight of our patients were lower than patients in North America and Europe, the volume of the contrast agent used in our study is far less the volumes of 150 ml or 140 ml reported in the literature [13,15]. In addition to the volume of the contrast agent, other factors such as flow rate of iodine injection, scan delay time, iodine concentration, heart rate, breathing frequency and cardiac output, might also affect the quality of enhancement in 4D-CT scanning [21].…”

Section: Discussionmentioning

confidence: 62%

“…Therefore, manufacturers have not provided a scanning protocol for contrast-enhanced 4D-CT imaging. However, there are still other studies in the literature that suggest that the application of contrast-enhanced 4D-CT imaging scans by administering a synchronized intravenous contrast injection improves target delineation in liver cancer, thoracic esophageal cancer, and pancreatic tumors, thereby, making this a feasible technique [13][14][15]. For example, the administration of a 150 ml contrast at a flow rate of 5 ml/s during a 4D-CT scan in order to improve the delineation of liver tumors has been reported [15].…”

Section: Introductionmentioning

confidence: 99%

“…For example, the administration of a 150 ml contrast at a flow rate of 5 ml/s during a 4D-CT scan in order to improve the delineation of liver tumors has been reported [15]. Furthermore, patients have been administered a total contrast medium volume of 140 ml at a rate of 2.9 ml/s during a contrast-enhanced 4D-CT scan for target volume definition in pancreatic ductal adenocarcinoma [13]. These protocols were specifically designed based on the experience of teams comprised of physicians and physicists in different radiotherapy departments.…”

Section: Introductionmentioning

confidence: 99%

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Optimization of a protocol for contrast-enhanced four-dimensional computed tomography imaging of thoracic tumors using minimal contrast agent

et al. 2021

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Purpose The accuracy of target delineation for node-positive thoracic tumors is dependent on both four-dimensional computed tomography (4D-CT) and contrast-enhanced three-dimensional (3D)-CT images; these scans enable the motion visualization of tumors and delineate the nodal areas. Combining the two techniques would be more effective; however, currently, there is no standard protocol for the contrast media injection parameters for contrast-enhanced 4D-CT (CE-4D-CT) scans because of its long scan durations and complexity. Thus, we aimed to perform quantitative and qualitative assessments of the image quality of single contrast-enhanced 4D-CT scans to simplify this process and improve the accuracy of target delineation in order to replace the standard clinical modality involved in administering radiotherapy for thoracic tumors. Methods Ninety consecutive patients with thoracic tumors were randomly and parallelly assigned to one of nine subgroups subjected to CE-4D-CT scans with the administration of contrast agent volume equal to the patient’s weight but different flow rate and scan delay time (protocol A1: flow rate of 2.0 ml/s, delay time of 15 s; A2: 2.0 ml/s, 20 s; A3: 2.0 ml/s, 25 s; B1: 2.5 ml/s, 15 s; B2: 2.5 ml/s, 20 s; B3: 2.5 ml/s, 25 s; C1: 3.0 ml/s, 15 s; C2: 3.0 ml/s, 20 s; C3: 3.0 ml/s, 25 s). The Hounsfield unit (HU) values of the thoracic aorta, pulmonary artery stem, pulmonary veins, carotid artery, and jugular vein were acquired for each protocol. Both quantitative and qualitative image analysis and delineation acceptability were assessed. Results The results revealed significant differences among the nine protocols. Enhancement of the vascular structures in mediastinal and perihilar regions was more effective with protocol A1 or A2; however, when interested in the region of superior mediastinum and supraclavicular fossa, protocol C2 or C3 is recommended. Conclusion Qualitatively acceptable enhancement on contrast-enhanced 4D-CT images of thoracic tumors can be obtained by varying the flow rate and delay time when minimal contrast agent is used.

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Section: Discussionmentioning

confidence: 62%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Optimization of a protocol for contrast-enhanced four-dimensional computed tomography imaging of thoracic tumors using minimal contrast agent

et al. 2021

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“…With the development of radiotherapy technology, including volumetric-modulated radiation therapy (VMAT), HT, gamma knife, image-guided radiation therapy (IGRT), 4-dimensional computed tomography (4D-CT), and breath-hold technique (BHT), it is now possible when treating pancreatic cancer to spare the gastrointestinal tract while still covering the target volume (8)(9)(10)(11)(12)(13). Compared with IMRT, HT can be performed with a dosimetrically comparable conformity index (CI) and lower gastrointestinal toxicity in pancreatic cancer (14).…”

Section: Introductionmentioning

confidence: 99%

Dosimetric feasibility on hypofractionated intensity-modulated radiotherapy and simultaneous integrated boost for locally advanced unresectable pancreatic cancer with helical tomotherapy

Feng¹,

Meng²,

Zhu³

2021

J Gastrointest Oncol

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Background: This dosimetric study on locally advanced pancreatic cancer (LAPC) and the surrounding gastrointestinal organs at risk (OARs) aimed at exploring the potential of further improving the internal dose and reducing the fractionation number by concurrent hypofractionated simultaneous integrated boost (SIB) radiotherapy using helical tomotherapy (HT). Methods: We collected computed tomography positioning images from a LAPC study of 17 consecutive patients. Gross tumor volume (GTV)1, GTV2, and GTV3 were defined as the GTV minus a margin of 3, 6, and 9 mm from the external part in all directions, respectively. Under the same physical parameters and limited dose on normal organs, each case had 4 sets of SIB radiotherapy plans. Upon dose escalation, we statistically analyzed the difference of dosimetric parameters received by the OARs between group A [planning target volume (PTV)/GTV=50 Gy/70 Gy] and the other groups. According to the equivalent bioradiotherapy formula, we calculated the hypofractionated standard dose by converting the average tolerated dose of each OAR with the corresponding number of fractions. Then, we compared the dose and volume parameters of the gastrointestinal tract from the less-than-20-fraction modes with the corresponding gastrointestinal hypofractionated standard dose. Results: For dose escalation, although there were a few differences in the parameters of the OAR between group A and group D, all OAR doses of group D (PTV/GTV/GTV1/GTV2/GTV3= 50 Gy/70 Gy/80 Gy/90 Gy/100 Gy) were within the limited dose range. In the hypofractionated mode, there was a statistically significant difference between the gastrointestinal dose-volume parameters and the doselimiting reference standard when the fraction number was less than 14 or 15 for group A or D, respectively. Conclusions: The dose of the internal target can be increased to 100 Gy with 15 fractions in the hypofractionated SIB radiotherapy for LAPC with HT. The corresponding tolerance dose of OARs may also be acceptable.

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“…The respiratory motion of abdominal tumors is an obstacle to radiotherapy (RT). 1 To assess the respiratory motion, four-dimensional computed tomography (4DCT) is utilized for radiation treatment planning in gastric lymphoma. 2,3 Recently, breath-hold image-guided radiotherapy (BH-IGRT) has been applied to treat gastric lymphoma to overcome the respiratory motion and reduce radiation doses for normal tissues.…”

Section: Introductionmentioning

confidence: 99%

Target coverage of daily cone-beam computed tomography in breath-hold image-guided radiotherapy for gastric lymphoma

et al. 2021

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Objectives: We evaluated retrospectively the daily target coverage using cone-beam computed tomography (CBCT) in breath-hold image-guided radiotherapy (BH-IGRT) for gastric lymphoma. Methods: BH-IGRT was performed using a prescribed dose of 30.6 Gy in 17 fractions for the whole stomach. We assessed the target coverage of the whole stomach on daily CBCT images (daily CTV), which was delineated individually by two observers. We evaluated V95% (percentage of volume receiving ≥95% of the prescribed dose) of daily CTV. Results: In total, 102 fractions from six patients were assessed. The mean V95% of daily CTV was 97.2%, which was over 95%. In 2 of 6 patients, the V95% of daily CTV was over 95% for either observer in all fractions. One patient had significant interobserver variation (p = 0.013). In 95 fractions (93%), the V95% of daily CTV was over 95% for either observer. Conclusions: Daily target coverage for CTV in BH-IGRT for gastric lymphoma seems to be favorable, even when using CBCT. Advances in knowledge: A previous study ascertained good daily target coverage in BH-IGRT for gastric lymphoma using in-room CT. Even when using CBCT in our study, daily target coverage for CTV in BH-IGRT for gastric lymphoma seems to be favorable.

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Respiratory motion of lymph node stations in pancreatic cancer: Analyses using contrast-enhanced four-dimensional computed tomography

Cited by 4 publications

References 22 publications

Optimization of a protocol for contrast-enhanced four-dimensional computed tomography imaging of thoracic tumors using minimal contrast agent

Optimization of a protocol for contrast-enhanced four-dimensional computed tomography imaging of thoracic tumors using minimal contrast agent

Dosimetric feasibility on hypofractionated intensity-modulated radiotherapy and simultaneous integrated boost for locally advanced unresectable pancreatic cancer with helical tomotherapy

Target coverage of daily cone-beam computed tomography in breath-hold image-guided radiotherapy for gastric lymphoma

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