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Delineation radiotherapy

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https://www.readbyqxmd.com/read/28331888/new-concept-on-an-integrated-interior-magnetic-resonance-imaging-and-medical-linear-accelerator-system-for-radiation-therapy
#1
Xun Jia, Zhen Tian, Yan Xi, Steve B Jiang, Ge Wang
Image guidance plays a critical role in radiotherapy. Currently, cone-beam computed tomography (CBCT) is routinely used in clinics for this purpose. While this modality can provide an attenuation image for therapeutic planning, low soft-tissue contrast affects the delineation of anatomical and pathological features. Efforts have recently been devoted to several MRI linear accelerator (LINAC) projects that lead to the successful combination of a full diagnostic MRI scanner with a radiotherapy machine. We present a new concept for the development of the MRI-LINAC system...
January 2017: Journal of Medical Imaging
https://www.readbyqxmd.com/read/28320428/a-topology-based-method-to-mitigate-the-dosimetric-uncertainty-caused-by-the-positional-variation-of-the-boost-volume-in-breast-conservative-radiotherapy
#2
Peng-Yi Lee, Chih-Yuan Lin, Shang-Wen Chen, Chun-Ru Chien, Chun-Nan Chu, Hsiu-Ting Hsu, Ji-An Liang, Ying-Jun Lin, An-Cheng Shiau
BACKGROUND: To improve local control rate in patients with breast cancer receiving adjuvant radiotherapy after breast conservative surgery, additional boost dose to the tumor bed could be delivered simultaneously via the simultaneous integrated boost (SIB) modulated technique. However, the position of tumor bed kept changing during the treatment course as the treatment position was aligned to bony anatomy. This study aimed to analyze the positional uncertainties between bony anatomy and tumor bed, and a topology-based approach was derived to stratify patients with high variation in tumor bed localization...
March 20, 2017: Radiation Oncology
https://www.readbyqxmd.com/read/28314252/clinical-target-volume-in-biliary-carcinoma-a-systematic-review-of-pathological-studies
#3
REVIEW
Ilaria Marinelli, Alessandra Guido, Lorenzo Fuccio, Andrea Farioli, Valeria Panni, Lucia Giaccherini, Alessandra Arcelli, Giorgio Ercolani, Giovanni Brandi, Silvia Cammelli, Andrea Galuppi, Gabriella Macchia, Rezarta Frakulli, Gian C Mattiucci, Francesco Cellini, Milly Buwenge, Matteo Renzulli, Francesco Deodato, Savino Cilla, Vincenzo Valentini, Vincenzo Tombolini, Rita Golfieri, Alessio G Morganti
BACKGROUND/AIM: Radiotherapy is a treatment option for both adjuvant and neo-adjuvant settings for biliary tract cancer. Guidelines on the delineation of the target volume of lymph nodes are lacking; only generic indications are available, without specific recommendations for different primary tumour locations (e.g. intrahepatic, extrahepatic biliary tract or gallbladder cancer). The aim of this study was to systematically review available literature to provide recommendations on lymph node target volume delineation in patients with unresectable biliary tumour...
March 2017: Anticancer Research
https://www.readbyqxmd.com/read/28306557/mri-micturating-urethrography-for-improved-urethral-delineation-in-prostate-radiotherapy-planning-a-case-study
#4
Robba Rai, Mark Sidhom, Karen Lim, Lucy Ohanessian, Gary P Liney
Stereotactic ablative body radiotherapy is used in prostate cancer to deliver a high dose of radiation to the tumour over a small number of treatments. This involves the simulation of the patient using both CT and MRI. Current practice is to insert an indwelling catheter (IDC) during CT to assist with visualisation of the urethra and subsequently minimise dose to this highly critical structure. However, this procedure is invasive and has an associated risk of infection. This is a case study, which demonstrates our initial experience of using a real-time non-invasive MRI technique to replace the use of IDC for prostate cancer patients...
March 17, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28306555/assessment-of-dosimetric-impact-of-system-specific-geometric-distortion-in-an-mri-only-based-radiotherapy-workflow-for-prostate
#5
C Gustafsson, F Nordström, E Persson, J Brynolfsson, L E Olsson
Dosimetric errors in a magnetic resonance imaging (MRI) only radiotherapy workflow may be caused by system specific geometric distortion from MRI. The aim of this study was to evaluate the impact on planned dose distribution and delineated structures for prostate patients, originating from this distortion. A method was developed, in which computer tomography (CT) images were distorted using the MRI distortion field. The displacement map for an optimized MRI treatment planning sequence was measured using a dedicated phantom in a 3 T MRI system...
March 17, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28303427/impact-of-endoscopic-ultrasonography-on-18-f-fdg-pet-ct-upfront-towards-patient-specific-esophageal-cancer-treatment
#6
J B Hulshoff, V E M Mul, H E M de Boer, W Noordzij, T Korteweg, H M van Dullemen, W B Nagengast, V Oppedijk, J P E N Pierie, John Th M Plukker
INTRODUCTION: In patients with potentially resectable esophageal cancer (EC), the value of endoscopic ultrasonography (EUS) after fluorine-18 labeled fluorodeoxyglucose positron emission tomography with computed tomography ((18)F-FDG-PET/CT) is questionable. Retrospectively, we assessed the impact of EUS after PET/CT on the given treatment in EC patients. METHODS: During the period 2009-2015, 318 EC patients were staged as T1-4aN0-3M0 with hybrid (18)F-FDG-PET/CT or (18)F-FDG-PET with CT and EUS if applicable in a nonspecific order...
March 16, 2017: Annals of Surgical Oncology
https://www.readbyqxmd.com/read/28301492/variability-in-target-delineation-of-cervical-carcinoma-a-korean-radiation-oncology-group-study-krog-15-06
#7
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
#8
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/28300372/lung-volume-reproducibility-under-abc-control-and-self-sustained-breath-holding
#9
Evangelia Kaza, Alex Dunlop, Rafal Panek, David J Collins, Matthew Orton, Richard Symonds-Tayler, Dualta McQuaid, Erica Scurr, Vibeke Hansen, Martin O Leach
An Active Breathing Coordinator (ABC) can be employed to induce breath-holds during CT imaging and radiotherapy of lung, breast and liver cancer, and recently during lung cancer MRI. The apparatus measures and controls respiratory volume, hence subject lung volume reproducibility is its principal measure of effectiveness. To assess ABC control quality, the intra-session reproducibility of ABC-induced lung volumes was evaluated and compared with that reached by applying the clinical standard of operator-guided self-sustained breath-holds on healthy volunteers during MRI...
March 2017: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28297426/mri-geometric-distortion-impact-on-tangential-whole-breast-imrt
#10
Amy Walker, Peter Metcalfe, Gary Liney, Vikneswary Batumalai, Kylie Dundas, Carri Glide-Hurst, Geoff P Delaney, Miriam Boxer, Mei Ling Yap, Jason Dowling, David Rivest-Henault, Elise Pogson, Lois Holloway
The purpose of this study was to determine the impact of magnetic resonance imaging (MRI) geometric distortions when using MRI for target delineation and planning for whole-breast, intensity-modulated radiotherapy (IMRT). Residual system distortions and combined systematic and patient-induced distortions are considered. This retrospective study investigated 18 patients who underwent whole-breast external beam radiotherapy, where both CT and MRIs were acquired for treatment planning. Distortion phantoms were imaged on two MRI systems, dedicated to radiotherapy planning (a wide, closed-bore 3T and an open-bore 1T)...
September 2016: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28297353/comparison-of-manual-and-automatic-mr-ct-registration-for-radiotherapy-of-prostate-cancer
#11
Anne Sofie Korsager, Jesper Carl, Lasse Riis Østergaard
In image-guided radiotherapy (IGRT) of prostate cancer, delineation of the clinical target volume (CTV) often relies on magnetic resonance (MR) because of its good soft-tissue visualization. Registration of MR and computed tomography (CT) is required in order to add this accurate delineation to the dose planning CT. An automatic approach for local MR-CT registration of the prostate has previously been developed using a voxel property-based registration as an alternative to a manual landmark-based registration...
May 2016: 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
#12
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
#13
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/28293971/a-modeling-study-of-functional-magnetic-resonance-imaging-to-individualize-target-definition-of-seminal-vesicles-for-external-beam-radiotherapy
#14
Sidsel Damkjær, Jakob B Thomsen, Svetlana I Petersen, Jens Peter Bangsgaard, Peter M Petersen, Ivan R Vogelius, Marianne C Aznar
BACKGROUND: Pre-treatment magnetic resonance imaging (MRI) can give patient-specific evaluation of suspected pathologically involved volumes in the seminal vesicles (SV) in prostate cancer patients. By targeting this suspicious volume we hypothesize that radiotherapy is more efficient without introducing more toxicity. In this study we evaluate the concept of using MRI-defined target volumes in terms of tumor control probability (TCP) and rectal normal tissue complication probability (NTCP)...
March 15, 2017: Acta Oncologica
https://www.readbyqxmd.com/read/28291912/improving-the-efficiency-of-breast-radiotherapy-treatment-planning-using-a-semi-automated-approach
#15
Robert A Mitchell, Philip Wai, Ruth Colgan, Anna M Kirby, Ellen M Donovan
OBJECTIVES: To reduce treatment planning times while maintaining plan quality through the introduction of semi-automated planning techniques for breast radiotherapy. METHODS: Automatic critical structure delineation was examined using the Smart Probabilistic Image Contouring Engine (SPICE) commercial autosegmentation software (Philips Radiation Oncology Systems, Fitchburg, WI) for a cohort of ten patients. Semiautomated planning was investigated by employing scripting in the treatment planning system to automate segment creation for breast step-and-shoot planning and create objectives for segment weight optimization; considerations were made for three different multileaf collimator (MLC) configurations...
January 2017: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28279179/the-effect-of-bowel-preparation-regime-on-interfraction-rectal-filling-variation-during-image-guided-radiotherapy-for-prostate-cancer
#16
Ali Hosni, Tara Rosewall, Timothy Craig, Vickie Kong, Andrew Bayley, Alejandro Berlin, Robert Bristow, Charles Catton, Padraig Warde, Peter Chung
BACKGROUND: This study aimed to investigate the tolerability and impact of milk of magnesia (MoM) on interfraction rectal filling during prostate cancer radiotherapy. METHODS: Two groups were retrospectively identified, each consisting of 40 patients with prostate cancer treated with radiotherapy to prostate+/-seminal vesicles, with daily image-guidance in 78Gy/39fractions/8 weeks. The first-group followed anti-flatulence diet with MoM started 3-days prior to planning-CT and continued during radiotherapy, while the second-group followed the same anti-flatulence diet only...
March 9, 2017: Radiation Oncology
https://www.readbyqxmd.com/read/28273355/evaluation-of-segmentation-methods-on-head-and-neck-ct-auto-segmentation-challenge-2015
#17
Patrik F Raudaschl, Paolo Zaffino, Gregory C Sharp, Maria Francesca Spadea, Antong Chen, Benoit M Dawant, Thomas Albrecht, Tobias Gass, Christoph Langguth, Marcel Lüthi, Florian Jung, Oliver Knapp, Stefan Wesarg, Richard Mannion-Haworth, Mike Bowes, Annaliese Ashman, Gwenael Guillard, Alan Brett, Graham Vincent, Mauricio Orbes-Arteaga, David Cárdenas-Peña, German Castellanos-Dominguez, Nava Aghdasi, Yangming Li, Angelique Berens, Kris Moe, Blake Hannaford, Rainer Schubert, Karl D Fritscher
PURPOSE: Automated delineation of structures and organs is a key step in medical imaging. However, due to the large number and diversity of structures and the large variety of segmentation algorithms a consensus is lacking as to which automated segmentation method works best for certain applications. Segmentation challenges are a good approach for unbiased evaluation and comparison of segmentation algorithms. METHODS: In this work we describe and present the results of the Head and Neck Auto-Segmentation Challenge 2015, a satellite event at the Medical Image Computing and Computer Assisted Interventions (MICCAI) 2015 conference...
March 8, 2017: Medical Physics
https://www.readbyqxmd.com/read/28263422/correlation-between-fluorodeoxyglucose-hotspots-on-pretreatment-positron-emission-tomography-ct-and-preferential-sites-of-local-relapse-after-chemoradiotherapy-for-head-and-neck-squamous-cell-carcinoma
#18
Anne Chaput, Jérémie Calais, Philippe Robin, Sébastien Thureau, David Bourhis, Romain Modzelewski, Ulrike Schick, Pierre Vera, Pierre-Yves Salaün, Ronan Abgral
BACKGROUND: The potential benefits of (18) F-fluoro-2-deoxy-D-glucose-positron emission tomography/CT (FDG-PET/CT) imaging for radiotherapy (RT) treatment planning of head and neck squamous cell carcinoma (HNSCC) are increasingly being recognized. It has been suggested that intratumoral subvolumes with high FDG avidity ("hotspots") are potential targets for selected dose escalation. The purposes of this study were to demonstrate that pre-RT FDG-PET/CT can identify intratumoral sites at increased risk of local relapse after RT and to determine an optimal threshold to delineate smaller RT target volumes that would facilitate RT dose escalation without impaired tolerance...
March 6, 2017: Head & Neck
https://www.readbyqxmd.com/read/28252445/comparing-the-dosimetric-impact-of-interfractional-anatomical-changes-in-photon-proton-and-carbon-ion-radiotherapy-for-pancreatic-cancer-patients
#19
Antonetta C Houweling, Koen Crama, Jorrit Visser, Kyohei Fukata, Coen R N Rasch, Tatsuya Ohno, Arjan Bel, Astrid van der Horst
Radiotherapy using charged particles is characterized by a low dose to the surrounding healthy organs, while delivering a high dose to the tumor. However, interfractional anatomical changes can greatly affect the robustness of particle therapy. Therefore, we compared the dosimetric impact of interfractional anatomical changes (i.e. body contour differences and gastrointestinal gas volume changes) in photon, proton and carbon ion therapy for pancreatic cancer patients. In this retrospective planning study, photon, proton and carbon ion treatment plans were created for 9 patients...
March 2, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28242140/mri-guided-lung-sbrt-present-and-future-developments
#20
REVIEW
Martin J Menten, Andreas Wetscherek, Martin F Fast
Stereotactic body radiotherapy (SBRT) is rapidly becoming an alternative to surgery for the treatment of early-stage non-small cell lung cancer patients. Lung SBRT is administered in a hypo-fractionated, conformal manner, delivering high doses to the target. To avoid normal-tissue toxicity, it is crucial to limit the exposure of nearby healthy organs-at-risk (OAR). Current image-guided radiotherapy strategies for lung SBRT are mostly based on X-ray imaging modalities. Although still in its infancy, magnetic resonance imaging (MRI) guidance for lung SBRT is not exposure-limited and MRI promises to improve crucial soft-tissue contrast...
February 24, 2017: Physica Medica: PM
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