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https://www.readbyqxmd.com/read/28453537/an-efficient-and-robust-mri-guided-radiotherapy-planning-approach-for-targeting-abdominal-organs-and-tumours-in-the-mouse
#1
Veerle Kersemans, John S Beech, Stuart Gilchrist, Paul Kinchesh, Philip D Allen, James Thompson, Ana L Gomes, Zenobia D'Costa, Luke Bird, Iain D C Tullis, Robert G Newman, Aurelien Corroyer-Dulmont, Nadia Falzone, Abul Azad, Katherine A Vallis, Owen J Sansom, Ruth J Muschel, Borivoj Vojnovic, Mark A Hill, Emmanouil Fokas, Sean C Smart
INTRODUCTION: Preclinical CT-guided radiotherapy platforms are increasingly used but the CT images are characterized by poor soft tissue contrast. The aim of this study was to develop a robust and accurate method of MRI-guided radiotherapy (MR-IGRT) delivery to abdominal targets in the mouse. METHODS: A multimodality cradle was developed for providing subject immobilisation and its performance was evaluated. Whilst CT was still used for dose calculations, target identification was based on MRI...
2017: PloS One
https://www.readbyqxmd.com/read/28433482/variations-of-target-volume-definition-and-daily-target-volume-localization-in-stereotactic-body-radiotherapy-for-early-stage-non-small-cell-lung-cancer-patients-under-abdominal-compression
#2
Chunhui Han, Sagus Sampath, Timothy E Schultheisss, Jeffrey Y C Wong
We aimed to compare gross tumor volumes (GTV) in 3-dimensional computed tomography (3DCT) simulation and daily cone beam CT (CBCT) with the internal target volume (ITV) in 4-dimensional CT (4DCT) simulation in stereotactic body radiotherapy (SBRT) treatment of patients with early-stage non-small cell lung cancer (NSCLC) under abdominal compression. We retrospectively selected 10 patients with NSCLC who received image-guided SBRT treatments under abdominal compression with daily CBCT imaging. GTVs were contoured as visible gross tumor on the planning 3DCT and daily CBCT, and ITVs were contoured using maximum intensity projection (MIP) images of the planning 4DCT...
April 19, 2017: Medical Dosimetry: Official Journal of the American Association of Medical Dosimetrists
https://www.readbyqxmd.com/read/28419246/quality-assurance-for-a-multicenter-phase-ii-study-of-stereotactic-ablative-radiotherapy-for-hepatocellular-carcinoma-%C3%A2-5-cm-a-planning-dummy-run
#3
Sun Hyun Bae, Mi-Sook Kim, Won Il Jang, Kum Bae Kim, Kwang Hwan Cho, Woo Chul Kim, Chang Yeol Lee, Eun Seog Kim, Chul Won Choi, A Ram Chang, Sunmi Jo, Jin-Young Kim
Objective: The Korean Radiation Oncology Group (12-02) investigated the outcome of stereotactic ablative radiotherapy for hepatocellular carcinoma ≤5 cm using 60 Gy in three fractions. To evaluate dosimetric differences and compliance in a multicenter trial, a planning dummy run procedure was performed. Methods: All six participating institutions were provided the contours of two dummy run cases. Plans were performed following the study protocol to cover the planning target volume with a minimum of 90% of the prescription dose and to satisfy the constraints for organs at risk...
April 13, 2017: Japanese Journal of Clinical Oncology
https://www.readbyqxmd.com/read/28414799/comprehensive-evaluation-of-ten-deformable-image-registration-algorithms-for-contour-propagation-between-ct-and-cone-beam-ct-images-in-adaptive-head-neck-radiotherapy
#4
Xin Li, Yuyu Zhang, Yinghua Shi, Shuyu Wu, Yang Xiao, Xuejun Gu, Xin Zhen, Linghong Zhou
Deformable image registration (DIR) is a critical technic in adaptive radiotherapy (ART) for propagating contours between planning computerized tomography (CT) images and treatment CT/cone-beam CT (CBCT) images to account for organ deformation for treatment re-planning. To validate the ability and accuracy of DIR algorithms in organ at risk (OAR) contour mapping, ten intensity-based DIR strategies, which were classified into four categories-optical flow-based, demons-based, level-set-based and spline-based-were tested on planning CT and fractional CBCT images acquired from twenty-one head & neck (H&N) cancer patients who underwent 6~7-week intensity-modulated radiation therapy (IMRT)...
2017: PloS One
https://www.readbyqxmd.com/read/28410685/evaluation-of-mesh-and-binary-based-contour-propagation-methods-in-4d-thoracic-radiotherapy-treatments-using-patient-4d-ct-images
#5
Yuanyuan Ma, Xinguo Liu, Zhongying Dai, Pengbo He, Yuanlin Yan, Guosheng Shen, Ping Yuan, Qiang Li
Based on four dimensional (4D) computed tomography (CT) images, mesh- and binary-based contour propagation algorithms for 4D thoracic radiotherapy treatments were evaluated. Gross tumor volumes (GTVs), lungs, hearts and spinal cords on the CT images at the end-exhale and end-inhale phases for six patients were delineated by the physician. All volumes of interest (VOIs) were automatically propagated from the end-exhale phase to the end-inhale phase using two propagation methods. The propagated VOIs were quantitatively compared with the VOIs contoured at the end-inhale phase by the physician using Dice Similarity Coefficient (DSC), Mean Slicewise Hausdorff Distance (MSHD), Center Of Mass (COM) displacement and volume difference...
April 2017: Physica Medica: PM
https://www.readbyqxmd.com/read/28404877/clinical-study-of-the-time-of-repeated-computed-tomography-and-replanning-for-patients-with-nasopharyngeal-carcinoma
#6
Xiujuan Gai, Yumei Wei, Hengmin Tao, Jian Zhu, Baosheng Li
PURPOSE: To study the necessity of repeat computed tomography (CT) scan and replanning and know a more accurate time using weekly kilovoltage cone beam computed tomography (kV-CBCT) scans for patients with nasopharyngeal carcinoma (NPC) during radiotherapy. METHODS AND MATERIALS: Thirteen NPC patients treated with IMRT were enrolled into this prospective study. Weekly pretreatment kV-CBCT scans were performed on the 1st, 6th, 11st, 16th, 21st and 26th radiation time, respectively...
March 31, 2017: Oncotarget
https://www.readbyqxmd.com/read/28402279/intensity-modulated-radiotherapy-with-fixed-collimator-jaws-for-locoregional-left-sided-breast-cancer-irradiation
#7
Juanqi Wang, Zhaozhi Yang, Weigang Hu, Zhi Chen, Xiaoli Yu, Xiaomao Guo
The purpose of this study is to evaluate the intensity modulated radiotherapy (IMRT) with the fixed collimator jaws technique (FJT) for the left breast and regional lymph node. The targeted breast tissue and the lymph nodes, and the normal tissues were contoured for 16 left-sided breast cancer patients previously treated with radiotherapy after lumpectomy. For each patient, treatment plans using different planning techniques, i.e., volumetric modulated arc therapy (VMAT), tangential IMRT (tangential-IMRT), and IMRT with FJT (FJT-IMRT) were developed for dosimetric comparisons...
March 28, 2017: Oncotarget
https://www.readbyqxmd.com/read/28398630/mitigating-differential-baseline-shifts-in-locally-advanced-lung-cancer-patients-using-an-average-anatomy-model
#8
Mehrsima Abdoli, Simon R van Kranen, Uros Stankovic, Maddalena M G Rossi, Jose S A Belderbos, Jan-Jakob Sonke
BACKGROUND AND PURPOSE: Differential baseline shifts between primary tumor and involved lymph nodes in locally advanced lung cancer patients compromise the accuracy of radiotherapy. The purpose of this study was to evaluate the performance of an average anatomy model (AAM) derived from repeat imaging and deformable registration to reduce these geometrical uncertainties. METHODS AND MATERIALS: An in-house implementation of a B-Spline deformable image registration (DIR) algorithm was first validated using three different validation approaches: 1) a circle method to test the consistency of the DIR, 2) fiducial marker target registration error, and 3) the recovery of a known deformation vector field (DVF)...
April 11, 2017: Medical Physics
https://www.readbyqxmd.com/read/28379850/a-novel-geometry-dosimetry-label-fusion-method-in-multi-atlas-segmentation-for-radiotherapy-a-proof-of-concept-study
#9
Jina Chang, Zhen Tian, Weiguo Lu, Xuejun Gu, Mingli Chen, Steve B Jiang
Multi-atlas segmentation (MAS) has been widely used to automate the delineation of organs at risk (OARs) for radiotherapy. Label fusion is a crucial step in MAS to cope with the segmentation variabilities among multiple atlases. However, most existing label fusion methods do not consider the potential dosimetric impact of the segmentation result. In this proof-of-concept study, we propose a novel geometry-dosimetry label fusion method for MAS-based OAR auto-contouring, which evaluates the segmentation performance in terms of both geometric accuracy and the dosimetric impact of the segmentation accuracy on the resulting treatment plan...
April 5, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28378320/the-impact-of-smart-metal-artefact-reduction-algorithm-for-use-in-radiotherapy-treatment-planning
#10
Connor Guilfoile, Peter Rampant, Michael House
The presence of metal artefacts in computed tomography (CT) create issues in radiation oncology. The loss of anatomical information and incorrect Hounsfield unit (HU) values produce inaccuracies in dose calculations, providing suboptimal patient treatment. Metal artefact reduction (MAR) algorithms were developed to combat these problems. This study provides a qualitative and quantitative analysis of the "Smart MAR" software (General Electric Healthcare, Chicago, IL, USA), determining its usefulness in a clinical setting...
April 4, 2017: Australasian Physical & Engineering Sciences in Medicine
https://www.readbyqxmd.com/read/28376237/use-of-image-registration-and-fusion-algorithms-and-techniques-in-radiotherapy-report-of-the-aapm-radiation-therapy-committee-task-group-no-132
#11
Kristy K Brock, Sasa Mutic, Todd R McNutt, Hua Li, Marc L Kessler
Image registration and fusion algorithms exist in almost every software system that creates or uses images in radiotherapy. Most treatment planning systems support some form of image registration and fusion to allow the use of multimodality and time-series image data and even anatomical atlases to assist in target volume and normal tissue delineation. Treatment delivery systems perform registration and fusion between the planning images and the in-room images acquired during the treatment to assist patient positioning...
April 4, 2017: Medical Physics
https://www.readbyqxmd.com/read/28351523/quality-assessment-of-delineation-and-dose-planning-of-early-breast-cancer-patients-included-in-the-randomized-skagen-trial-1
#12
Giulio Francolini, Mette S Thomsen, Esben S Yates, Carine Kirkove, Ingelise Jensen, Egil S Blix, Claus Kamby, Mette H Nielsen, Mechthild Krause, Martin Berg, Ingvil Mjaaland, Andreas Schreiber, Unn-Miriam Kasti, Kristian Boye, Birgitte V Offersen
BACKGROUND AND PURPOSE: To report on a Quality assessment (QA) of Skagen Trial 1, exploring hypofractionation for breast cancer patients with indication for regional nodal radiotherapy. MATERIAL AND METHODS: Deviations from protocol regarding target volume delineations and dose parameters (Dmin, Dmax, D98%, D95% and D2%) from randomly selected dose plans were assessed. Target volume delineation according to ESTRO guidelines was obtained through atlas based automated segmentation and centrally approved as gold standard (GS)...
March 25, 2017: Radiotherapy and Oncology: Journal of the European Society for Therapeutic Radiology and Oncology
https://www.readbyqxmd.com/read/28339289/the-role-of-delineation-education-programs-for-improving-interobserver-variability-in-target-volume-delineation-in-gastric-cancer
#13
Cem Onal, Mustafa Cengiz, Ozan C Guler, Yemliha Dolek, Serdar Ozkok
OBJECTIVE: To assess whether delineation courses for radiation oncologists improve interobserver variability in target volume delineation for post-operative gastric cancer radiotherapy planning. METHODS: 29 radiation oncologists delineated target volumes in a gastric cancer patient. An experienced radiation oncologist lectured about delineation based on contouring atlas and delineation recommendations. After the course, the radiation oncologists, blinded to the previous delineation, provided delineation for the same patient...
May 2017: British Journal of Radiology
https://www.readbyqxmd.com/read/28327466/regional-deep-hyperthermia-impact-of-observer-variability-in-ct-based-manual-tissue-segmentation-on-a-simulated-temperature-distribution
#14
Bassim Aklan, Josefin Hartmann, Diana Zink, Hadi Siavooshhaghighi, Ricarda Merten, Florian Putz, Oliver Ott, Rainer Fietkau, Christoph Bert
The aim of this study was to systematically investigate the influence of inter- and intra-observer segmentation variation of tumor and organs at risk on the simulated temperature coverage of the target. CT scans of six patients with tumors in the pelvic region acquired for radiotherapy treatment planning were used for the hyperthermia treatment planning. To study the effect of inter-observer variation, three observers manually segmented in the CT images of each patient the following structures: fat, muscle, bone and bladder...
March 22, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28318880/highly-conformal-craniospinal-radiotherapy-techniques-can-underdose-the-cranial-clinical-target-volume-if-leptomeningeal-extension-through-skull-base-exit-foramina-is-not-contoured
#15
D J Noble, T Ajithkumar, J Lambert, I Gleeson, M V Williams, S J Jefferies
AIMS: Craniospinal irradiation (CSI) remains a crucial treatment for patients with medulloblastoma. There is uncertainty about how to manage meningeal surfaces and cerebrospinal fluid (CSF) that follows cranial nerves exiting skull base foramina. The purpose of this study was to assess plan quality and dose coverage of posterior cranial fossa foramina with both photon and proton therapy. MATERIALS AND METHODS: We analysed the radiotherapy plans of seven patients treated with CSI for medulloblastoma and primitive neuro-ectodermal tumours and three with ependymoma (total n = 10)...
March 15, 2017: Clinical Oncology: a Journal of the Royal College of Radiologists
https://www.readbyqxmd.com/read/28301492/variability-in-target-delineation-of-cervical-carcinoma-a-korean-radiation-oncology-group-study-krog-15-06
#16
Ji Hyeon Joo, Young Seok Kim, Byung Chul Cho, Chi Young Jeong, Won Park, Hak Jae Kim, Won Sup Yoon, Mee Sun Yoon, Ji-Yoon Kim, Jin Hwa Choi, Youngmin Choi, Joo-Young Kim
PURPOSE: To determine inter-observer variability in target volume definition of cervical cancer in radical and adjuvant radiotherapy (RT) settings. METHODS: Eight physicians contoured CTVs of 2 patients underwent definitive and postoperative RT. Each volume was analyzed using the individual/median volume ratio and generalized conformity index (CIgen). And center of mass (COM) of each contour was calculated. Expert agreement was quantified using an expectation maximization algorithm for Simultaneous Truth and Performance Level Estimation (STAPLE)...
2017: PloS One
https://www.readbyqxmd.com/read/28300381/comparison-of-ct-images-with-average-intensity-projection-free-breathing-and-mid-ventilation-for-dose-calculation-in-lung-cancer
#17
Chirasak Khamfongkhruea, Sangutid Thongsawad, Chirapha Tannanonta, Sasikarn Chamchod
The purpose of this study was to compare three computed tomography (CT) images under different conditions-average intensity projection (AIP), free breathing (FB), mid-ventilation (MidV)-used for radiotherapy contouring and planning in lung cancer patients. Two image sets derived from four-dimensional CT (4DCT) acquisition (AIP and MidV) and three-dimensional CT with FB were generated and used to plan for 29 lung cancer patients. Organs at risk (OARs) were delineated for each image. AIP images were calculated with 3D conformal radiotherapy (3DCRT) and intensity-modulated radiation therapy (IMRT)...
March 2017: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28297341/assessment-of-monte-carlo-algorithm-for-compliance-with-rtog-0915-dosimetric-criteria-in-peripheral-lung-cancer-patients-treated-with-stereotactic-body-radiotherapy
#18
Damodar Pokhrel, Sumit Sood, Rajeev Badkul, Hongyu Jiang, Christopher McClinton, Christopher Lominska, Parvesh Kumar, Fen Wang
The purpose of the study was to evaluate Monte Carlo-generated dose distributions with the X-ray Voxel Monte Carlo (XVMC) algorithm in the treatment of peripheral lung cancer patients using stereotactic body radiotherapy (SBRT) with non-protocol dose-volume normalization and to assess plan outcomes utilizing RTOG 0915 dosimetric compliance criteria. The Radiation Therapy Oncology Group (RTOG) protocols for non-small cell lung cancer (NSCLC) currently require radiation dose to be calculated using tissue density heterogeneity corrections...
May 2016: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28296324/the-feasibility-of-atlas-based-automatic-segmentation-of-mri-for-h-n-radiotherapy-planning
#19
Kieran Wardman, Robin J D Prestwich, Mark J Gooding, Richard J Speight
Atlas-based autosegmentation is an established tool for segmenting structures for CT-planned head and neck radiotherapy. MRI is being increasingly integrated into the planning process. The aim of this study is to assess the feasibility of MRI-based, atlas-based autosegmentation for organs at risk (OAR) and lymph node levels, and to compare the segmentation accuracy with CT-based autosegmentation. Fourteen patients with locally advanced head and neck cancer in a prospective imaging study underwent a T1-weighted MRI and a PET-CT (with dedicated contrast-enhanced CT) in an immobilization mask...
July 2016: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28296320/a-comparative-study-based-on-image-quality-and-clinical-task-performance-for-ct-reconstruction-algorithms-in-radiotherapy
#20
Hua Li, Steven Dolly, Hsin-Chen Chen, Mark A Anastasio, Daniel A Low, Harold H Li, Jeff M Michalski, Wade L Thorstad, Hiram Gay, Sasa Mutic
CT image reconstruction is typically evaluated based on the ability to reduce the radiation dose to as-low-as-reasonably-achievable (ALARA) while maintaining acceptable image quality. However, the determination of common image quality metrics, such as noise, contrast, and contrast-to-noise ratio, is often insufficient for describing clinical radiotherapy task performance. In this study we designed and implemented a new comparative analysis method associating image quality, radiation dose, and patient size with radiotherapy task performance, with the purpose of guiding the clinical radiotherapy usage of CT reconstruction algorithms...
July 2016: Journal of Applied Clinical Medical Physics
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