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Image Guided Radiotherapy

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https://www.readbyqxmd.com/read/28428474/evaluation-of-absorbed-dose-for-cbct-in-image-guided-radiation-therapy-comparison-of-each-devices-and-facilities
#1
Yumiko Kitazato, Noriyuki Kuga, Katsutoshi Shirieda, Masahiro Enzaki, Yuji Nakaguchi, Yoshinobu Shimohigashi, Toshihisa Kawasaki, Masahiko Toyoda, Daisuke Kawahara, Fujio Araki, Shinji Kawamura
Recently, intensity-modulated radiation therapy (IMRT) is used worldwide, highly accurate verification of the location using image-guided radiation therapy (IGRT) has become critical. However, the use of cone-beam computed tomography (CBCT) to ascertain the location each time raises concerns about its influence on radiotherapy dosage and increased radiation exposure. The purpose of this study was to measure the absorbed dose using nine kilovoltage (kV) devices and two megavoltage (MV) devices (total 11 devices) at eight facilities, compare the absorbed dose among the devices, and assess the characteristics of the respective devices to ensure optimal clinical operation...
2017: Nihon Hoshasen Gijutsu Gakkai Zasshi
https://www.readbyqxmd.com/read/28425431/characterization-of-spatial-distortion-in-a-0-35t-mri-guided-radiotherapy-system
#2
John S Ginn, Nzhde Agazaryan, Minsong Cao, Umar Baharom, Daniel Low, Yingli Yang, Yu Gao, Peng Hu, Percy Lee, James Lamb
Spatial distortion results in image deformation that can degrade accurate targeting and dose calculations in MRI-guided adaptive radiotherapy. The authors present a comprehensive assessment of a 0.35T MRI-guided radiotherapy system's spatial distortion using two commercially-available phantoms with regularly spaced markers. Images of the spatial integrity phantoms were acquired using five clinical protocols on the MRI-guided radiotherapy machine with the radiotherapy gantry positioned at various angles. Software was developed to identify and localize all phantom markers using a template matching approach...
April 20, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28416260/late-genitourinary-toxicity-outcomes-in-300-prostate-cancer-patients-treated-with-dose-escalated-image-guided-intensity-modulated-radiotherapy
#3
K Byrne, G Hruby, A Kneebone, D Whalley, L Guo, P McCloud, T Eade
AIMS: To quantify and qualify late genitourinary toxicity in a cohort of patients with localised prostate cancer treated with image-guided intensity-modulated radiotherapy (IMRT) to doses ≥78 Gy. MATERIALS AND METHODS: The cohort consisted of 300 patients treated with definitive dose-escalated IMRT between 2007 and 2013. Ninety-seven patients received 78-80 Gy in 38 fractions, and 203 received 82-84 Gy in 40 fractions. International Prostate Symptoms Score (IPSS) and supplemental quality of life data were recorded at baseline, weekly during treatment and at follow-up...
April 14, 2017: Clinical Oncology: a Journal of the Royal College of Radiologists
https://www.readbyqxmd.com/read/28410682/integrated-digital-tomosynthesis-for-patient-positioning-of-image-guided-radiation-therapy
#4
Hui Yan, Jian-Rong Dai
PURPOSE: Digital Tomosynthesis (DTS), originally developed for diagnostic applications, has been recently introduced to image guided radiotherapy (IGRT). Due to limited scan range, DTS was featured by anisotropic spatial resolution. A new approach, integrated DTS (IDTS), was developed to improve image resolution of DTS for patient positioning in IGRT. MATERIALS AND METHODS: For registration purpose, both on-board IDTS (O-IDTS) and reference IDTS (R-IDTS) were required...
April 2017: Physica Medica: PM
https://www.readbyqxmd.com/read/28409355/percutaneous-mr-guided-focal-cryoablation-for-recurrent-prostate-cancer-following-radiation-therapy-retrospective-analysis-of-iceball-margins-and-outcomes
#5
Christiaan G Overduin, Sjoerd F M Jenniskens, J P Michiel Sedelaar, Joyce G R Bomers, Jurgen J Fütterer
OBJECTIVES: To evaluate iceball margins after magnetic resonance (MR)-guided focal salvage prostate cryoablation and determine the correlation with local outcome. METHODS: A retrospective review was performed on 47 patients that underwent percutaneous MR-guided focal cryoablation for biopsy-proven locally recurrent prostate cancer after primary radiotherapy. Preprocedural diagnostic and intraprocedural MR images were analysed to derive three-directional iceball margins...
April 13, 2017: European Radiology
https://www.readbyqxmd.com/read/28405657/a-triple-synergistic-strategy-for-combinational-photo-radiotherapy-and-multi-modality-imaging-based-on-hyaluronic-acid-hybridized-polyaniline-coated-ws2-nanodots
#6
Jinping Wang, Xiaojuan Pang, Xiaoxiao Tan, Yilin Song, Li Liu, Qing You, Qi Sun, Fengping Tan, Nan Li
In this study, we report a strategy for integrating hyaluronic acid (HA), polyaniline (PANI), WS2 nanodots (WS2), and chlorin e6 (Ce6) into a single nanoplatform (HA-WS2@PANI/Ce6) for fluorescence, photoacoustic, and computed tomography multi-modality imaging-guided trimodal photothermal/radiation/photodynamic combination therapy of tumors. The WS2 nanodot core is used as the radiosensitizer with the PANI shell as the hyperthermal agent and the photosensitizer reservoir. HA and Ce6 were adsorbed on the outer shell for tumor targeting and photodynamic therapy, respectively...
April 13, 2017: Nanoscale
https://www.readbyqxmd.com/read/28405102/measurement-of-total-scatter-factor-for-stereotactic-cones-with-plastic-scintillation-detector
#7
Suresh H Chaudhari, Rishabh Dobhal, Rajesh A Kinhikar, Sudarshan S Kadam, Deepak D Deshpande
Advanced radiotherapy modalities such as stereotactic radiosurgery (SRS) and image-guided radiotherapy may employ very small beam apertures for accurate localized high dose to target. Accurate measurement of small radiation fields is a well-known challenge for many dosimeters. The purpose of this study was to measure total scatter factors for stereotactic cones with plastic scintillation detector and its comparison against diode detector and theoretical estimates. Measurements were performed on Novalis Tx(™) linear accelerator for 6MV SRS beam with stereotactic cones of diameter 6 mm, 7...
January 2017: Journal of Medical Physics
https://www.readbyqxmd.com/read/28401808/associations-between-volume-changes-and-spatial-dose-metrics-for-the-urinary-bladder-during-local-versus-pelvic-irradiation-for-prostate-cancer
#8
Oscar Casares-Magaz, Vitali Moiseenko, Austin Hopper, Niclas Johan Pettersson, Maria Thor, Rick Knopp, Joseph O Deasy, Ludvig Paul Muren, John Einck
BACKGROUND: Inter-fractional variation in urinary bladder volumes during the course of radiotherapy (RT) for prostate cancer causes deviations between planned and delivered doses. This study compared planned versus daily cone-beam CT (CBCT)-based spatial bladder dose distributions, for prostate cancer patients receiving local prostate treatment (local treatment) versus prostate including pelvic lymph node irradiation (pelvic treatment). MATERIAL AND METHODS: Twenty-seven patients (N = 15 local treatment; N = 12 pelvic treatment) were treated using daily image-guided RT (1...
April 12, 2017: Acta Oncologica
https://www.readbyqxmd.com/read/28391025/establishment-and-validation-of-m1-stage-subdivisions-for-de-novo-metastatic-nasopharyngeal-carcinoma-to-better-predict-prognosis-and-guide-treatment
#9
Xiong Zou, Rui You, Huai Liu, Yu-Xiang He, Guo-Feng Xie, Zhi-Hai Xie, Ji-Bin Li, Rou Jiang, Li-Zhi Liu, Li Li, Meng-Xia Zhang, You-Ping Liu, Yi-Jun Hua, Ling Guo, Chao-Nan Qian, Hai-Qiang Mai, Dong-Ping Chen, Ying Luo, Liang-Fang Shen, Ming-Huang Hong, Ming-Yuan Chen
BACKGROUND: To better manage patients with de novo metastatic NPC (mNPC) including easily identifying individuals' survival outcomes and accurately choosing the most suitable treatment. MATERIALS AND METHODS: Three independent cohorts of mNPC patients (a training set of n = 462, an internal prospective validation set of n = 272 and an external prospective validation set of n = 243) were studied. The radiological characteristics of distant metastases, including number of metastatic locations, number of metastatic lesions and size of metastatic lesions, were carefully defined based on imaging data...
April 6, 2017: European Journal of Cancer
https://www.readbyqxmd.com/read/28390002/a-tool-for-validating-mri-guided-strategies-a-digital-breathing-ct-mri-phantom-of-the-abdominal-site
#10
Chiara Paganelli, Paul Summers, Chiara Gianoli, Massimo Bellomi, Guido Baroni, Marco Riboldi
Dynamic magnetic resonance imaging (MRI) is emerging as the elected image modality for organ motion quantification and management in image-guided radiotherapy. However, the lack of validation tools is an open issue for image guidance in the abdominal and thoracic organs affected by organ motion due to respiration. We therefore present an abdominal four-dimensional (4D) CT/MRI digital phantom, including the estimation of MR tissue parameters, simulation of dedicated abdominal MR sequences, modeling of radiofrequency coil response and noise, followed by k-space sampling and image reconstruction...
April 8, 2017: Medical & Biological Engineering & Computing
https://www.readbyqxmd.com/read/28374321/reduced-late-urinary-toxicity-with-high-dose-intensity-modulated-radiotherapy-using-intra-prostate-fiducial-markers-for-localized-prostate-cancer
#11
A Zapatero, M Roch, D Büchser, P Castro, L Fernández-Banda, G Pozo, O Liñán, C Martin de Vidales, A Cruz-Conde, F García-Vicente
BACKGROUND/PURPOSE: To evaluate the impact of intensity-modulated radiotherapy (IMRT) with intra-prostate fiducial markers image-guided radiotherapy (IGRT) on the incidence of late urinary toxicity compared to 3D conformal radiotherapy (3DCRT) for patients with prostate cancer (PC). METHODS AND MATERIALS: We selected 733 consecutive patients with localized PC treated with dose-escalation radiotherapy between 2001 and 2014. Eligibility criteria were radiation dose >72...
April 3, 2017: Clinical & Translational Oncology
https://www.readbyqxmd.com/read/28363486/magnitude-and-variability-of-respiratory-induced-diaphragm-motion-in-children-during-image-guided-radiotherapy
#12
Sophie C Huijskens, Irma W E M van Dijk, Jorrit Visser, Coen R N Rasch, Tanja Alderliesten, Arjan Bel
BACKGROUND AND PURPOSE: To analyse the variability of respiratory motion during image-guided radiotherapy in paediatric cancer patients and to investigate possible relationships thereof with patient-specific factors. MATERIAL AND METHODS: Respiratory-induced diaphragm motion was retrospectively analysed on 480 cone beam CTs acquired during the treatment course of 45 children (<18years). The cranial-caudal positions of the top of the right diaphragm in exhale and inhale phases were manually selected in the projection images...
March 28, 2017: Radiotherapy and Oncology: Journal of the European Society for Therapeutic Radiology and Oncology
https://www.readbyqxmd.com/read/28351527/imaging-practices-and-radiation-doses-from-imaging-in-radiotherapy
#13
Teemu Siiskonen, Sampsa Kaijaluoto, Tudor Florea
Modern radiotherapy treatments require frequent imaging for accurate patient positioning relative to the therapeutic radiation beam. Imaging practices in five Finnish radiotherapy clinics were assessed and discussed from the patient dose optimization point of view. The results show that imaging strategies are not jointly established and variations exist. The organ absorbed doses depend on imaging technique and imaging frequency. In particular, organ doses from the cone beam computed tomography can have very large variations (a factor of 10-50 in breast imaging and factor of 5 in prostate imaging)...
March 25, 2017: Physica Medica: PM
https://www.readbyqxmd.com/read/28350540/construction-of-a-biomechanical-head-and-neck-motion-model-as-a-guide-to-evaluation-of-deformable-image-registration
#14
Hendrik Teske, Kathrin Bartelheimer, Jan Meis, Rolf Bendl, Eva Stoiber, Kristina Giske
The use of deformable image registration methods in the context of adaptive radiotherapy leads to uncertainties in the simulation of the administered dose distributions during the treatment course. Evaluation of these methods is a prerequisite to decide if a plan adaptation will improve the individual treatment. Current approaches using manual references limit the validity of evaluation, especially for low contrast regions. In particular for the head and neck region, the highly flexible anatomy and the low soft tissue contrast in control images pose a challenge to image registration and its evaluation...
March 28, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28338470/reducing-scan-angle-using-adaptive-prior-knowledge-for-a-limited-angle-intrafraction-verification-live-system-for-conformal-arc-radiotherapy
#15
Yawei Zhang, Fang-Fang Yin, You Zhang, Lei Ren
PURPOSE: To develop an adaptive prior knowledge guided image estimation technique to reduce the scan angle needed in the Limited-Angle Intrafraction Verification (LIVE) system for 4D-CBCT reconstruction. METHOD: The LIVE system has been previously developed to reconstruct 4D volumetric images on-the-fly during arc treatment for intrafraction target verification and dose calculation. In this study, we developed an adaptive constrained free-form deformation reconstruction technique in LIVE to further reduce the scanning angle needed to reconstruct the 4D-CBCT images for faster intrafraction verification...
March 24, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28337425/post-prostatectomy-image-guided-radiotherapy-the-invisible-target-concept
#16
REVIEW
Florent Vilotte, Mickael Antoine, Maxime Bobin, Igor Latorzeff, Stéphane Supiot, Pierre Richaud, Laurence Thomas, Nicolas Leduc, Stephane Guérif, Jone Iriondo-Alberdi, Renaud de Crevoisier, Paul Sargos
In the era of intensity-modulated radiation therapy, image-guided radiotherapy (IGRT) appears crucial to control dose delivery and to promote dose escalation while allowing healthy tissue sparing. The place of IGRT following radical prostatectomy is poorly described in the literature. This review aims to highlight some key points on the different IGRT techniques applicable to prostatic bed radiotherapy. Furthermore, methods used to evaluate target motion and to reduce planning target volume margins will also be explored...
2017: Frontiers in Oncology
https://www.readbyqxmd.com/read/28335794/tumor-motion-changes-in-stereotactic-body-radiotherapy-for-liver-tumors-an-evaluation-based-on-four-dimensional-cone-beam-computed-tomography-and-fiducial-markers
#17
Yoshinobu Shimohigashi, Ryo Toya, Tetsuo Saito, Osamu Ikeda, Masato Maruyama, Keisuke Yonemura, Yuji Nakaguchi, Yudai Kai, Yasuyuki Yamashita, Natsuo Oya, Fujio Araki
BACKGROUND: For stereotactic body radiation therapy (SBRT) of liver tumors, tumor motion induced by respiration must be taken into account in planning and treatment. We evaluated whether liver tumor motion at the planning simulation represents liver tumor motion during SBRT, and estimated inter- and intrafractional tumor motion changes in patients undergoing liver SBRT. METHODS: Ten patients underwent four-dimensional cone-beam computed tomography (4D-CBCT) image-guided liver SBRT with abdominal compression (AC) and fiducial markers...
March 23, 2017: Radiation Oncology
https://www.readbyqxmd.com/read/28317152/-68-ga-psma-pet-for-radiation-treatment-planning-in-prostate-cancer-recurrences-after-surgery-individualized-medicine-or-new-standard-in-salvage-treatment
#18
Gregor Habl, Katharina Sauter, Kilian Schiller, Sabrina Dewes, Tobias Maurer, Matthias Eiber, Stephanie E Combs
BACKGROUND: (68) Ga-PSMA-PET imaging is a novel promising diagnostic tool to locate early biochemical failure after radical prostatectomy (RP) in prostate cancer (PC) patients. Exact knowledge of the relapse location may result in changes of the therapy concept aside from changes to the TNM stage. To gain data for this approach, we evaluated PC patients receiving (68) Ga-PSMA-PET imaging before salvage radiotherapy (RT). METHODS AND MATERIALS: In this study, 100 patients with biochemical failure after RP± prior RT who underwent (68) Ga-PSMA PET/CT or PET/MRI were evaluated undergoing salvage RT in our department...
March 20, 2017: Prostate
https://www.readbyqxmd.com/read/28315948/-18f-fmiso-pet-study-of-hypoxia-in-gliomas-before-surgery-correlation-with-molecular-markers-of-hypoxia-and-angiogenesis
#19
Lien Bekaert, Samuel Valable, Emmanuèle Lechapt-Zalcman, Keven Ponte, Solène Collet, Jean-Marc Constans, Guénaëlle Levallet, Karim Bordji, Edwige Petit, Pierre Branger, Evelyne Emery, Alain Manrique, Louisa Barré, Myriam Bernaudin, Jean-Sébastien Guillamo
PURPOSE: Hypoxia in gliomas is associated with tumor resistance to radio- and chemotherapy. However, positron emission tomography (PET) imaging of hypoxia remains challenging, and the validation of biological markers is, therefore, of great importance. We investigated the relationship between uptake of the PET hypoxia tracer [18F]-FMISO and other markers of hypoxia and angiogenesis and with patient survival. PATIENTS AND METHODS: In this prospective single center clinical study, 33 glioma patients (grade IV: n = 24, III: n = 3, and II: n = 6) underwent [18F]-FMISO PET and MRI including relative cerebral blood volume (rCBV) maps before surgery...
March 18, 2017: European Journal of Nuclear Medicine and Molecular Imaging
https://www.readbyqxmd.com/read/28300372/lung-volume-reproducibility-under-abc-control-and-self-sustained-breath-holding
#20
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
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