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David jaffray

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https://www.readbyqxmd.com/read/29762285/cone-beam-computed-tomography-guided-navigation-in-complex-osteotomies-improves-accuracy-at-all-competence-levels-a-study-assessing-accuracy-and-reproducibility-of-joint-sparing-bone-cuts
#1
Amir Sternheim, Aidin Kashigar, Michael Daly, Harley Chan, Jimmy Qiu, Robert Weersink, David Jaffray, Jonathan C Irish, Peter C Ferguson, Jay S Wunder
BACKGROUND: The objective of this study was to assess the accuracy and reproducibility of a novel cone-beam computed tomography (CBCT)-guided navigation system designed for osteotomies with joint-sparing bone cuts. METHODS: Eighteen surgeons participated in this study. First, 3 expert tumor surgeons resected bone tumors in 3 Sawbones tumor models identical to actual patient scenarios. They first performed these osteotomies without navigation and then performed them using a navigation system and 3-dimensional (3D) planning tools based on CBCT imaging...
May 16, 2018: Journal of Bone and Joint Surgery. American Volume
https://www.readbyqxmd.com/read/29762137/spatial-frequency-performance-limitations-of-radiation-dose-optimization-and-beam-positioning
#2
James M P Stewart, Shawn Stapleton, Naz Chaudary, Patricia E Lindsay, David A Jaffray
The flexibility and sophistication of modern radiotherapy treatment planning and delivery methods have advanced techniques to improve the therapeutic ratio. Contemporary dose optimization and calculation algorithms facilitate radiotherapy plans which closely conform the three-dimensional dose distribution to the target, with beam shaping devices and image guided field targeting ensuring the fidelity and accuracy of treatment delivery. Ultimately, dose distribution conformity is limited by the maximum deliverable dose gradient; shallow dose gradients challenge techniques to deliver a tumoricidal radiation dose while minimizing dose to surrounding tissue...
May 15, 2018: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/29726358/how-advances-in-imaging-will-affect-precision-radiation-oncology
#3
David A Jaffray, Shiva Das, Paula M Jacobs, Robert Jeraj, Philippe Lambin
Radiation oncology is 1 of the most structured disciplines in medicine. It is of a highly technical nature with reliance on robotic systems to deliver intervention, engagement of diverse expertise, and early adoption of digital approaches to optimize and execute the application of this highly effective cancer treatment. As a localized intervention, the dependence on sensitive, specific, and accurate imaging to define the extent of disease, its heterogeneity, and adjacency to normal tissues directly affects the therapeutic ratio...
June 1, 2018: International Journal of Radiation Oncology, Biology, Physics
https://www.readbyqxmd.com/read/29723251/spatiotemporal-assessment-of-spontaneous-metastasis-formation-using-multimodal-in-vivo-imaging-in-her2-and-triple-negative-metastatic-breast-cancer-xenograft-models-in-mice
#4
Inga B Fricke, Raquel De Souza, Lais Costa Ayub, Giulio Francia, Robert Kerbel, David A Jaffray, Jinzi Zheng
BACKGROUND: Preclinical breast cancer models recapitulating the clinical course of metastatic disease are crucial for drug development. Highly metastatic cell lines forming spontaneous metastasis following orthotopic implantation were previously developed and characterized regarding their biological and histological characteristics. This study aimed to non-invasively and longitudinally characterize the spatiotemporal pattern of metastasis formation and progression in the MDA-MB-231-derived triple negative LM2-4 and HER2+ LM2-4H2N cell lines, using bioluminescence imaging (BLI), contrast enhanced computed tomography (CT), fluorescence imaging, and 2-deoxy-2-[fluorine-18]fluoro-D-glucose positron emission tomography ([18F]FDG-PET)...
2018: PloS One
https://www.readbyqxmd.com/read/29680257/measurement-of-tumor-hypoxia-in-patients-with-locally-advanced-cervical-cancer-using-positron-emission-tomography-with-18-f-fluoroazomyin-arabinoside
#5
Kathy Han, Tina Shek, Douglass Vines, Brandon Driscoll, Anthony Fyles, David Jaffray, Harald Keller, Ur Metser, Melania Pintilie, Jason Xie, Ivan Yeung, Michael Milosevic
PURPOSE: To assess cervical tumor hypoxia using the hypoxia tracer 18 F-fluoroazomycin arabinoside (18 F-FAZA) and compare different reference tissues and thresholds for quantifying tumor hypoxia. METHODS AND MATERIALS: Twenty-seven patients with cervical cancer were studied prospectively by positron emission tomography (PET) imaging with 18 F-FAZA before starting standard chemoradiation. The hypoxic volume was defined as all voxels within a tumor (T) with standardized uptake values (SUVs) greater than 3 standard deviations from the mean gluteus maximus muscle SUV value (M) or SUVs greater than 1 to 1...
March 2, 2018: International Journal of Radiation Oncology, Biology, Physics
https://www.readbyqxmd.com/read/29645282/quality-control-methods-for-linear-accelerator-radiation-and-mechanical-axes-alignment
#6
Daniel Létourneau, Harald Keller, Nathan Becker, Md Nurul Amin, Bernhard Norrlinger, David A Jaffray
PURPOSE: The delivery accuracy of highly conformal dose distributions generated using intensity modulation and collimator, gantry and couch degrees of freedom is directly affected by the quality of the alignment between the radiation beam and the mechanical axes of a linear accelerator. For this purpose, quality control (QC) guidelines recommend a tolerance of ± 1 mm for the coincidence of the radiation and mechanical isocenters. Traditional QC methods for assessment of radiation and mechanical axes alignment (based on pointer alignment) are time consuming and complex tasks that provide limited accuracy...
April 12, 2018: Medical Physics
https://www.readbyqxmd.com/read/29493533/design-and-implementation-of-a-3d-mr-ct-geometric-image-distortion-phantom-analysis-system-for-stereotactic-radiosurgery
#7
A Z Damyanovich, M Rieker, B Zhang, J-P Bissonnette, D A Jaffray
The design, construction and application of a multimodality, 3D magnetic resonance/computed tomography (MR/CT) image distortion phantom and analysis system for stereotactic radiosurgery (SRS) is presented. The phantom is characterized by (1) a 1 × 1 × 1 (cm)3 MRI/CT-visible 3D-Cartesian grid; (2) 2002 grid vertices that are 3D-intersections of MR-/CT-visible 'lines' in all three orthogonal planes; (3) a 3D-grid that is MR-signal positive/CT-signal negative; (4) a vertex distribution sufficiently 'dense' to characterize geometrical parameters properly, and (5) a grid/vertex resolution consistent with SRS localization accuracy...
March 27, 2018: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/29476017/administration-of-hypoxia-activated-prodrug-evofosfamide-after-conventional-adjuvant-therapy-enhances-therapeutic-outcome-and-targets-cancer-initiating-cells-in-preclinical-models-of-colorectal-cancer
#8
Jennifer Haynes, Trevor D McKee, Andrew Haller, Yadong Wang, Cherry Leung, Deena M A Gendoo, Evelyne Lima-Fernandes, Antonija Kreso, Robin Wolman, Eva Szentgyorgyi, Douglass C Vines, Benjamin Haibe-Kains, Bradly G Wouters, Ur Metser, David A Jaffray, Myles Smith, Catherine A O'Brien
Purpose: Cancer-initiating cells (C-IC) have been described in multiple cancer types, including colorectal cancer. C-ICs are defined by their capacity to self-renew, thereby driving tumor growth. C-ICs were initially thought to be static entities; however, recent studies have determined these cells to be dynamic and influenced by microenvironmental cues such as hypoxia. If hypoxia drives the formation of C-ICs, then therapeutic targeting of hypoxia could represent a novel means to target C-ICs. Experimental Design: Patient-derived colorectal cancer xenografts were treated with evofosfamide, a hypoxia-activated prodrug (HAP), in combination with 5-fluorouracil (5-FU) or chemoradiotherapy (5-FU and radiation; CRT)...
May 1, 2018: Clinical Cancer Research: An Official Journal of the American Association for Cancer Research
https://www.readbyqxmd.com/read/29469936/2d-3d-registration-for-cranial-radiation-therapy-using-a-3d-kv-cbct-and-a-single-limited-field-of-view-2d-kv-radiograph
#9
Reshma Munbodh, Jonathan Ps Knisely, David A Jaffray, Douglas J Moseley
PURPOSE: We present and evaluate a fully automated 2D-3D intensity-based registration framework using a single limited field-of-view (FOV) 2D kV radiograph and a 3D kV CBCT for 3D estimation of patient setup errors during brain radiotherapy. METHODS: We evaluated two similarity measures, the Pearson correlation coefficient on image intensity values (ICC) and maximum likelihood measure with Gaussian noise (MLG), derived from the statistics of transmission images...
May 2018: Medical Physics
https://www.readbyqxmd.com/read/29360154/monte-carlo-analysis-of-beam-blocking-grid-design-parameters-scatter-estimation-and-the-importance-of-electron-backscatter
#10
Gregory J Bootsma, Lei Ren, Hong Zhang, Jian-Yue Jin, David A Jaffray
PURPOSE: Beam blocking grids provide a simple and direct measurement of the scattered photon signal which degrades image quality in x-ray imaging systems, such as cone-beam CT (CBCT). This study evaluates the scatter estimation accuracy of the beam blocking method to optimize the design parameters of the grid system (e.g., grid thickness, source-to-grid distance (SGD), septa width, air interspace, and grid ratio) using Monte Carlo (MC) simulations. METHOD: A MC model of a CBCT imaging system with a beam blocking grid in place is made using code based on EGSnrc, with the x-ray tube portion of the simulation including electron backscatter between the anode and cathode...
March 2018: Medical Physics
https://www.readbyqxmd.com/read/29273939/impact-of-tissue-transport-on-pet-hypoxia-quantification-in-pancreatic-tumours
#11
Edward Taylor, Jennifer Gottwald, Ivan Yeung, Harald Keller, Michael Milosevic, Neesha C Dhani, Iram Siddiqui, David W Hedley, David A Jaffray
BACKGROUND: The clinical impact of hypoxia in solid tumours is indisputable and yet questions about the sensitivity of hypoxia-PET imaging have impeded its uptake into routine clinical practice. Notably, the binding rate of hypoxia-sensitive PET tracers is slow, comparable to the rate of diffusive equilibration in some tissue types, including mucinous and necrotic tissue. This means that tracer uptake on the scale of a PET imaging voxel-large enough to include such tissue and hypoxic cells-can be as much determined by tissue transport properties as it is by hypoxia...
December 22, 2017: EJNMMI Research
https://www.readbyqxmd.com/read/29246584/serial-4dct-4dpet-imaging-to-predict-and-monitor-response-for-locally-advanced-non-small-cell-lung-cancer-chemo-radiotherapy
#12
Jean-Pierre Bissonnette, Mei Ling Yap, Katy Clarke, Andrea Shessel, Jane Higgins, Douglass Vines, Eshetu G Atenafu, Nathan Becker, Claudia Leavens, Andrea Bezjak, David A Jaffray, Alexander Sun
BACKGROUND AND PURPOSE: A FDG-PET/CT image feature with optimal prognostic potential for locally-advanced non-small cell lung cancer (LA-NSCLC) patients has yet to be identified, and neither has the optimal time for FDG-PET/CT response assessment; furthermore, nodal features have been largely ignored in the literature. We propose to identify image features or imaging time point with maximal prognostic power. MATERIALS AND METHODS: Consecutive consenting patients with LA-NSCLC receiving curative intent CRT were enrolled...
February 2018: Radiotherapy and Oncology: Journal of the European Society for Therapeutic Radiology and Oncology
https://www.readbyqxmd.com/read/29228390/altered-brain-morphology-after-focal-radiation-reveals-impact-of-off-target-effects-implications-for-white-matter-development-and-neurogenesis
#13
Kiran G Beera, Yu-Qing Li, Jun Dazai, James Stewart, Shannon Egan, Mashal Ahmed, C Shun Wong, David A Jaffray, Brian J Nieman
Background: Children with brain tumors treated with cranial radiation therapy (RT) often exhibit cognitive late effects, commonly associated with reduced white matter (WM) volume and decreased neurogenesis. The impact of radiation damage in particular regions or tissues on brain development as a whole has not been elucidated. Methods: We delivered whole-brain or focal radiation (8 Gy single dose) to infant mice. Focal treatments targeted white matter (anterior commissure), neuronal (olfactory bulbs), or neurogenic (subventricular zone) regions...
November 2, 2017: Neuro-oncology
https://www.readbyqxmd.com/read/29173909/voxel-by-voxel-correlation-between-radiologically-radiation-induced-lung-injury-and-dose-after-image-guided-intensity-modulated-radiotherapy-for-lung-tumors
#14
Michele Avanzo, Sara Barbiero, Marco Trovo, Jean-Pierre Bissonnette, Rajesh Jena, Joseph Stancanello, Giovanni Pirrone, Fabio Matrone, Emilio Minatel, Cristina Cappelletto, Carlo Furlan, David A Jaffray, Giovanna Sartor
PURPOSE: To correlate radiation dose to the risk of severe radiologically-evident radiation-induced lung injury (RRLI) using voxel-by-voxel analysis of the follow-up computed tomography (CT) of patients treated for lung cancer with hypofractionated helical Tomotherapy. METHODS AND MATERIALS: The follow-up CT scans from 32 lung cancer patients treated with various regimens (5, 8, and 25 fractions) were registered to pre-treatment CT using deformable image registration (DIR)...
October 2017: Physica Medica: PM
https://www.readbyqxmd.com/read/29173397/global-impact-of-radiotherapy-in-oncology-saving-one-million-lives-by-2035
#15
Yolande Lievens, Mary Gospodarowicz, Surbhi Grover, David Jaffray, Danielle Rodin, Julie Torode, Mei Ling Yap, Eduardo Zubizarreta
No abstract text is available yet for this article.
November 2017: Radiotherapy and Oncology: Journal of the European Society for Therapeutic Radiology and Oncology
https://www.readbyqxmd.com/read/29077574/monte-carlo-simulation-of-radiation-transport-and-dose-deposition-from-locally-released-gold-nanoparticles-labeled-with-111-in-177-lu-or-90-y-incorporated-into-tissue-implantable-depots
#16
Priscilla Lai, Zhongli Cai, Jean-Philippe Pignol, Eli Lechtman, Shahram Mashouf, Yijie Lu, Mitchell A Winnik, David A Jaffray, Raymond M Reilly
Permanent seed implantation (PSI) brachytherapy is a highly conformal form of radiation therapy but is challenged with dose inhomogeneity due to its utilization of low energy radiation sources. Gold nanoparticles (AuNP) conjugated with electron emitting radionuclides have recently been developed as a novel form of brachytherapy and can aid in homogenizing dose through physical distribution of radiolabeled AuNP when injected intratumorally (IT) in suspension. However, the distribution is unpredictable and precise placement of many injections would be difficult...
October 27, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28976913/monte-carlo-simulation-of-radiation-transport-and-dose-deposition-from-locally-released-gold-nanoparticles-labeled-with-sup-111-sup-in-sup-177-sup-lu-or-sup-90-sup-y-incorporated-into-tissue-implantable-depots
#17
Priscilla Lai, Zhongli Cai, Jean-Philippe Pignol, Eli Lechtman, Shahram Mashouf, Yijie Lu, Mitchell A Winnik, David A Jaffray, Raymond M Reilly
Permanent seed implantation (PSI) brachytherapy is a highly conformal form of radiation therapy but is challenged with dose inhomogeneity due to its utilization of low energy radiation sources. Gold nanoparticles (AuNP) conjugated with electron emitting radionuclides have recently been developed as a novel form of brachytherapy and can aid in homogenizing dose through physical distribution of radiolabeled AuNP when injected intratumorally (i.t.) in suspension. However, the distribution is unpredictable and precise placement of many injections would be difficult...
October 4, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28859933/evaluation-of-high-dose-volumetric-ct-to-reduce-inter-observer-delineation-variability-and-ptv-margins-for-prostate-cancer-radiotherapy
#18
Hamideh Alasti, Young-Bin Cho, Charles Catton, Alejandro Berlin, Peter Chung, Andrew Bayley, Aaron Vandermeer, Vickie Kong, David Jaffray
PURPOSE: The aim was to determine whether the enhanced soft tissue contrast provided by high-dose volumetric CT (HDVCT) can reduce inter-observer variability in delineating prostate compared to helical conventional CT (CCT) scans and 3T MRI scans for patients undergoing radical prostate cancer radiotherapy. Secondly, to quantify the potential PTV reduction with decreased inter-observer variability. MATERIALS AND METHODS: A 320 slice volumetric CT scanner was used...
October 2017: Radiotherapy and Oncology: Journal of the European Society for Therapeutic Radiology and Oncology
https://www.readbyqxmd.com/read/28764881/dosimetric-impact-of-intrafraction-changes-in-mr-guided-high-dose-rate-hdr-brachytherapy-for-prostate-cancer
#19
Alexandra Rink, Jette Borg, Anna Simeonov, Gerald O'Leary, Joelle Helou, Cynthia Ménard, Peter Chung, David A Jaffray, Alejandro Berlin
PURPOSE: To assess changes in implant and treatment volumes through the course of a prostate high-dose-rate brachytherapy procedure and their impact on plan quality metrics. METHODS AND MATERIALS: Sixteen MRI-guided high-dose-rate procedures included a post-treatment MR (ptMR) immediately after treatment delivery (135 min between MR scans). Target and organs at risk (OARs) were contoured, and catheters were reconstructed. The delivered treatment plan was applied to the ptMR image set...
January 2018: Brachytherapy
https://www.readbyqxmd.com/read/28760449/tumor-microenvironment-determines-response-to-a-heat-activated-thermosensitive-liposome-formulation-of-cisplatin-in-cervical-carcinoma
#20
Yannan N Dou, Naz Chaudary, Martin C Chang, Michael Dunne, Huang Huang, David A Jaffray, Michael Milosevic, Christine Allen
Significant heterogeneity in the tumor microenvironment of human cervical cancer patients is known to challenge treatment outcomes in this population. The current standard of care for cervical cancer patients is radiation therapy and concurrent cisplatin (CDDP) chemotherapy. Yet this treatment strategy fails to control loco-regional disease in 10-30% of patients. In order to improve the loco-regional control rate, a thermosensitive liposome formulation of CDDP (HTLC) was developed to increase local concentrations of drug in response to mild hyperthermia (HT)...
July 29, 2017: Journal of Controlled Release: Official Journal of the Controlled Release Society
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