Four dimensional radiotherapy: a review of current technologies and modalities

Moorrees, Joshua; Bezak, Eva

doi:10.1007/s13246-012-0178-5

Cited by 16 publications

(7 citation statements)

References 37 publications

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“…Internal organ motion caused by respiration or heartbeat is considerable. It is crucial to verify reproducibility of target location prior to treatment for lung and abdominal cancer patients [1][2][3]. Recently, the external and surface monitoring systems, such as RPM and OSMS (Varian Medical System, Palo Alto, USA), were used for patient positioning in radiotherapy.…”

Section: Introductionmentioning

confidence: 99%

Four-Dimensional Cone-Beam Computed Tomography Image Compression Using Video Encoder for Radiotherapy

Yan

Dai

2020

J Digit Imaging

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Four dimensional cone-beam computed tomography (4D-CBCT) images were widely used for patient positing and target localization in radiotherapy. As consisting of multiple CBCT sets, it needs more time and space for data transferring and storage. In this study the feasibility of applying video coding algorithms for 4D-CBCT image compression was investigated. Prior to compression 4D-CBCT images were arranged in an order based on breathing phase or slice location for input sequence of video encoder. Median filtering was applied to suppress noise and artifact of 4D-CBCT for improved image quality. Three popular video coding algorithms (Motion JPEG 2000, Motion JPEG AVI, and MPEG-4) were tested and their performances were evaluated on a publicly available 4D-CBCT database. The average compression ratio of MPEG-4 was 135, while the values of Motion JPEG AVI and Motion JPEG 2000 were 16 and 7, respectively. The compression rate of two ordering methods was comparable and the location-based ordering method was slightly higher. With pre-processing of median filtering, the inter-frame similarity of input sequence was improved and the resulting compression rate was increased. MPEG-4 provided extremely higher compression rate for 4D-CBCT images. The ordering method based on slice location resulted in higher compression rate than the ordering method based on breathing phase. The median filtering was effective in improving inter-frame similarity and resulted in higher compression rate. The video coding algorithms are not only applicable for 4D image modalities but also feasible for serial 3D image modalities. Keywords 4D-CBCT . Video coding algorithm . Image compression * Jianrong Dai

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Section: Introductionmentioning

confidence: 99%

Four-Dimensional Cone-Beam Computed Tomography Image Compression Using Video Encoder for Radiotherapy

Yan

Dai

2020

J Digit Imaging

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“…This information might be used for example to gate the beam or to adapt the treatment delivery in real time in the case of tumor tracking. 8,9 To address this need, several platforms have been developed to enable real time tumor position monitoring. Some of the earliest approaches to this were to utilize the MV imaging systems typically integrated on modern linacs to monitor the location of implanted fiducials within the beam portal throughout the treatment delivery.…”

Section: Introductionmentioning

confidence: 99%

Dosimetric impact of intrafraction rotations in stereotactic prostate radiotherapy: A subset analysis of the TROG 15.01 SPARK trial

Wolf

Nicholls

Hunter

et al. 2019

Radiotherapy and Oncology

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Background & Purpose Accurate delivery of radiotherapy is critical to achieve optimal treatment outcomes. Interfraction translational IGRT is now standard, and intrafraction motion management is becoming accessible. Some platforms can report both translational and rotational movements in real time. This study aims to quantify the dosimetric impact of observed intrafraction rotation of the prostate measured using monitoring software. Materials & Methods A dose grid resampling algorithm was used to model the dosimetric impact of prostate rotations for 20 patients on a SBRT prostate clinical trial. Translations were corrected before and during treatment, but rotations were not. Real time rotation data was acquired using KIM and a cumulative histogram analysis performed. Prostate volumes were rotated by the range of observed angles and used to calculate DVH data. Results The pitch axis had a higher range of observed rotations resulting in only 7 patients spending at least 90% of the beam on time across all fractions within rotation angles resulting in PTV D95%≥36Gy in this axis. The yaw and roll axes saw 17 and 15 patients respectively achieving this criterion. All but one of 20 patients exceeded CTV D98% ≥36Gy for all observed rotation angles. Conclusions Current CTV-PTV margins do not result in compromised CTV dose coverage due to inter and intrafraction prostate rotations in the absence of other uncertainties. Reduced PTV dosing is due to the extremely conformal treatment delivery but is unlikely to be clinically deleterious. Prostate standard IGRT should continue to focus on correcting any observed translational movements. Margin reduction could be explored in conjunction with other uncertainties. Highlights • Prostate intrafraction rotations are typically non-symmetrical about the pitch axis • Observed rotations resulted in reduced PTV dose coverage for many patients • CTV coverage was maintained for virtually all observed rotations • Existing SBRT CTV-PTV margins sufficient to account for intrafraction rotations

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“…Image guided radiation therapy has technically achieved minimization of the setup margin, and thus the optimization of the ITV margin is an important factor in the determination of the planning target volume. Four-dimensional CT (4DCT) is one of the most important techniques to determine the ITV margin for RT planning 9 . Several studies that reported on esophageal tumor motion using 4DCT have been published 10, 11, 12, 13, 14, 15, 16.…”

Section: Introductionmentioning

confidence: 99%

Esophageal motion characteristics in thoracic esophageal cancer: Impact of clinical stage T4 versus stages T1-T3

Kobayashi

Myojin

Shimizu

et al. 2016

Advances in Radiation Oncology

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PurposeThe main purpose was to investigate the differences of the esophageal motion (EM) and the internal target volume (ITV) margins for the esophagus between clinical T1-T3 (cT1-T3) and cT4 cases, using 4-dimensional computed tomography. A secondary purpose was to assess the metastatic lymph nodal motion (NM) and the ITV margins for lymph nodes (LNs) using the datasets of patients with nodal involvement pathologically defined.Methods and materialsWe analyzed patients with thoracic esophageal cancer consecutively treated with definitive chemoradiation, measuring the EM and the ITV margins in the left-right, anteroposterior, and superoinferior directions. All esophageal contours were divided at the carina. The EM and NM were measured from the displacement of the centroid point between 0% images (at the end of inhalation) and 50% images (at the end of exhalation). The ITV margins were defined as the maximum distance in each direction from the clinical target volume at the 4-dimensional computed tomography average images to the intersection of the clinical target volume at the 0% and 50% images of complete coverage in each patient.ResultsThe EM below the carina in cT4 was significantly smaller than that in cT1-T2 in all directions (P < .01) and than that in cT3 in all directions (left-right: P = .03, anteroposterior and superoinferior: P < .01). The EM in the case of a cT4 tumor located below the carina was smaller than that in the case of cT4 tumor located above the carina. The NM of abdominal-LNs was much larger than that of cervicothoracic-LNs and the EM below the carina. These tendencies were similar in the ITV measurements.ConclusionsThe EM and the ITV margins in cT4 were significantly smaller than those in cT1-T3. The NM and the ITV margins of abdominal LNs were much larger than those of cervicothoracic LNs and the esophagus. In clinical radiation therapy planning for esophageal cancer, we should take cT stage into consideration.

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Four dimensional radiotherapy: a review of current technologies and modalities

Cited by 16 publications

References 37 publications

Four-Dimensional Cone-Beam Computed Tomography Image Compression Using Video Encoder for Radiotherapy

Four-Dimensional Cone-Beam Computed Tomography Image Compression Using Video Encoder for Radiotherapy

Dosimetric impact of intrafraction rotations in stereotactic prostate radiotherapy: A subset analysis of the TROG 15.01 SPARK trial

Esophageal motion characteristics in thoracic esophageal cancer: Impact of clinical stage T4 versus stages T1-T3

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