Mazza A.,Medical Physics, Inc.
Clinical Nuclear Medicine | Year: 2017
ABSTRACT: This 16-year-old boy presented with acute retrosternal pain possibly representing acute myocardial infarction. Cardiac enzymes were within reference ranges. There were marked increases in metanephrine to 3299 μg/24 h (reference, <400 μg/24 h), normetanephrine to 1309 μg/24 h (reference, 0–390 μg/24 h), and chromogranin A to 1605 ng/mL (reference, 0–150 μg/24 h). An incidental left adrenal mass was found during CTPA performed to exclude pulmonary embolism. I-MIBG scintigraphy was negative, and genetic screening detected SDHB (succinate dehydrogenase syndrome subunit B) gene mutation. Based on the gene mutation, F-DOPA PET/CT was performed, confirming a left-sided pheochromocytoma. Copyright © 2017 Wolters Kluwer Health, Inc. All rights reserved.
News Article | April 18, 2017
Miami Cancer Institute expects to be the primary destination for cancer patients in the southeastern United States, Latin America and the Caribbean. The center provides all cancer services under one roof. Besides the proton facility, Miami Cancer Institute hosts other front-line treatment modalities from Accuray, Elekta, Varian and ViewRay. The customer has chosen C-RAD’s SIGRT (Surface Image Guided Radiation Therapy) solution to optimize patient safety before and during treatment. Due to the precision of proton therapy in delivering radiation dose to the tumor, a high level of accuracy is required for patient positioning before and during treatment. The Catalyst™ system will be delivered with the complete software suite with modules for Respiratory Gating, Patient Setup and Positioning and Motion Monitoring. The C-RAD SIGRT solution provides a continuous monitoring of the patient during a treatment fraction. Patient motion above a clinically defined threshold will interrupt the treatment beam. C-RAD provides interfaces to seamlessly integrate its products into the workflow. In April 2015, C-RAD validated its respiratory gating interface for IBA proton and particle therapy. It is the intention to cooperate with Miami Cancer Institute to develop a dedicated clinical workflow for proton therapy. C-RAD Sentinel 4DCT is an easy-to-use, laser-based optical surface scanning system with functionality for 4D CT reconstruction and gated imaging in a CT room. It also provides reference images for patient positioning. Alonso N. Gutierrez, PhD, MBA, Chief of Medical Physics, from Miami Cancer Institute says: “We are excited to welcome this technology to our state-of-the-art proton center. Using the Catalyst HD system, we believe we will be able to improve our initial patient set up, monitor any patient motion during beam-on and gate the proton beam in an efficient manner to facilitate patient throughput.” “We are honored to work with the team from Miami Cancer Institute on this prestigious project. It is our intention to build-up this site as an international reference site in the proton therapy landscape.” says Tim Thurn, CEO and President of C-RAD AB, “The overall development within radiation therapy is encouraging for C-RAD. The demand for accurate patient positioning is continuously increasing, and I am confident that C-RAD will contribute to help cure more cancer patients with our cutting-edge solutions and as being a trusted partner to our customers.” The order amounts to a total of approximately 7,5 mSEK and includes the delivery of the systems and a service contract for a period of five years. Ít is expected to commence delivery and installation in the second quarter 2017. The project is booked as order intake in the second quarter 2017. Baptist Health is the largest healthcare organization in South Florida, with seven hospitals (Baptist Hospital, Baptist Children’s Hospital, Doctors Hospital, Homestead Hospital, Mariners Hospital, South Miami Hospital and West Kendall Baptist Hospital) and more than 30 outpatient and urgent care facilities spanning three counties. Not-for-profit, faith-based Baptist Health has more than 15,000 employees and 2,200 affiliated physicians, and also includes Baptist Heath Medical Group, Baptist Outpatient Services and internationally renowned centers of excellence. Baptist Health Foundation, the organization’s fundraising arm, supports services at all hospitals and facilities. Baptist Health is listed by Fortune magazine as one of the 100 Best Companies to Work for in America (No. 23 in the nation) and has remained on the list for 15 years. It is also recognized as one of the World’s Most Ethical Companies for the fifth year in a row by Ethisphere Institute. C-RAD develops innovative solutions for use in advanced radiation therapy. The C-RAD group offers products and solutions for patient positioning, tumor localization and radiation treatment systems. All product development is conducted in three fully owned subsidiaries: C-RAD Positioning AB, C-RAD Imaging AB and C-RAD Innovation AB, all of which are located in Uppsala, Sweden. C-RAD has established three companies for direct sales: C-RAD Inc. in the US, C-RAD GmbH in Germany and C-RAD WOFE in China. Cyrpa International SPRL, a Franco-Belgian laser company, is a wholly owned subsidiary whose operations are integrated. C-RAD AB is listed on NASDAQ Stockholm. For more information on C-RAD, please visit http://www.c-rad.com This information is information that C-RAD AB (publ) is obliged to make public pursuant to the EU Market Abuse Regulation. The information was submitted for publication at 08:30 CET on April 18, 2017.
Multiparametric prostate mr imaging with T2-weighted, diffusion-weighted, and dynamic contrast-enhanced sequences : Are all pulse sequences necessary to detect locally recurrent prostate cancer after radiation therapy
Jung S.I.,Konkuk University |
Gultekin D.H.,Medical Physics, Inc. |
Zheng J.,Biostatistics |
Moskowitz C.S.,Biostatistics |
Zelefsky M.J.,Sloan Kettering Cancer Center
Radiology | Year: 2013
Purpose: To compare diagnostic accuracy of T2-weighted magnetic resonance (MR) imaging with that of multiparametric (MP) MR imaging combining T2-weighted imaging with diffusion-weighted (DW) MR imaging, dynamic contrast material-enhanced (DCE) MR imaging, or both in the detection of locally recurrent prostate cancer (PCa) after radiation therapy (RT). Materials and Methods: This retrospective HIPAA-compliant study was approved by the institutional review board; informed consent was waived. Fifty-three men (median age, 70 years) suspected of having post-RT recurrence of PCa underwent MP MR imaging, including DW and DCE sequences, within ±months after biopsy. Two readers independently evaluated the likelihood of PCa with a five-point scale for T2-weighted imaging alone, T2-weighted imaging with DW imaging, T2-weighted imaging with DCE imaging, and T2-weighted imaging with DW and DCE imaging, with at least a 4-week interval between evaluations. Areas under the receiver operating characteristic curve (AUC) were calculated. Interreader agreement was assessed, and quantitative parameters (apparent diffusion coefficient [ADC], volume transfer constant [Ktrans], and rate constant [kep]) were assessed at sextantand patient-based levels with generalized estimating equations and the Wilcoxon rank sum test, respectively. Results: At biopsy, recurrence was present in 35 (66%) of 53 patients. In detection of recurrent PCa, T2-weighted imaging with DW imaging yielded higher AUCs (reader 1, 0.79-0.86; reader 2, 0.75-0.81) than T2-weighted imaging alone (reader 1, 0.63-0.67; reader 2, 0.46-0.49 [P ? .014 for all]). DCE sequences did not contribute significant incremental value to T2-weighted imaging with DW imaging (reader 1, P . .99; reader 2, P = .35). Interreader agreement was higher for combinations of MP MR imaging than for T2-weighted imaging alone (k = 0.34-0.63 vs k = 0.17-0.20). Medians of quantitative parameters differed significantly (P < .0001 to P = .0233) between benign tissue and PCa (ADC, 1.64 31023 mm2/sec vs 1.13 31023 mm2/sec; Ktrans, 0.1±min21 vs 0.33 min21; kep, 0.3±min21 vs 0.62 min21). Conclusion: MP MR imaging has greater accuracy in the detection of recurrent PCa after RT than T2-weighted imaging alone, with no additional benefit if DCE is added to T2-weighted imaging and DW imaging. © 2013 RSNA.
Ashburner M.J.,Medical Physics, Inc. |
Tudor S.,Medical Physics, Inc.
Journal of Applied Clinical Medical Physics | Year: 2014
When the planning target volume (PTV), extends close to or beyond the skin, inverse-planned intensity-modulated radiotherapy can boost the fluence from tangential angles to superficial parts of the PTV due to the buildup effect. This can result in significant regions of high dose upon a small movement in the patient's position. We analyzed different methods of reducing this effect in the TomoTherapy planning system, including using pretend bolus, clipping the PTV back from the skin surface, and combinations of both. No alternative technique was seen to be unconditionally superior to a 5 mm planning bolus. A clip distance of 3 mm gave acceptable results, but consideration should be given to the reduction in minimum dose or increase in maximum dose seen in clip distances just 1 mm less or more, respectively, when treating head and neck cases in TomoTherapy.
Kennedy A.S.,Wake Radiology Oncology |
Kennedy A.S.,North Carolina State University |
Kleinstreuer C.,North Carolina State University |
Basciano C.A.,North Carolina State University |
Dezarn W.A.,Medical Physics, Inc.
International Journal of Radiation Oncology Biology Physics | Year: 2010
Purpose: Radioembolization (RE) via yttrium-90 (90Y) microspheres is an effective and safe treatment for unresectable liver malignancies. However, no data are available regarding the impact of local blood flow dynamics on 90Y-microsphere transport and distribution in the human hepatic arterial system. Methods and Materials: A three-dimensional (3-D) computer model was developed to analyze and simulate blood-microsphere flow dynamics in the hepatic arterial system with tumor. Supplemental geometric and flow data sets from patients undergoing RE were also available to validate the accuracy of the computer simulation model. Specifically, vessel diameters, curvatures, and branching patterns, as well as blood flow velocities/pressures and microsphere characteristics (i.e., diameter and specific gravity), were measured. Three-dimensional computer-aided design software was used to create the vessel geometries. Initial trials, with 10,000 noninteracting microspheres released into the hepatic artery, used resin spheres 32-μm in diameter with a density twice that of blood. Results: Simulations of blood flow subject to different branch-outlet pressures as well as blood-microsphere transport were successfully carried out, allowing testing of two types of microsphere release distributions in the inlet plane of the main hepatic artery. If the inlet distribution of microspheres was uniform (evenly spaced particles), a greater percentage would exit into the vessel branch feeding the tumor. Conversely, a parabolic inlet distribution of microspheres (more particles around the vessel center) showed a high percentage of microspheres exiting the branch vessel leading to the normal liver. Conclusions: Computer simulations of both blood flow patterns and microsphere dynamics have the potential to provide valuable insight on how to optimize 90Y-microsphere implantation into hepatic tumors while sparing normal tissue. © 2010 Elsevier Inc. All rights reserved.
Saeed N.P.,Ageing and Stroke Medicine |
Panerai R.B.,Medical Physics, Inc. |
Panerai R.B.,University of Leicester |
Horsfield M.A.,Medical Physics, Inc. |
And 2 more authors.
Cerebrovascular Diseases | Year: 2013
Background: It is known that dynamic cerebral autoregulation (dCA) is acutely impaired following ischaemic stroke (IS). However, the influence of stroke subtype, the affected (AF) and unaffected (UA) hemispheres, and the effects of a methodological approach on dCA estimates in stroke are all inconclusive. Therefore, we studied cortical and subcortical acute IS (AIS) patients to test the primary hypotheses that (1) dCA is impaired in stroke subtypes when compared to controls, (2) dCA impairment is more pronounced in the AF compared with the UA hemisphere, and (3) similar results are obtained with both spontaneous blood pressure (BP) fluctuation techniques, and sudden induced BP changes by thigh cuff deflation. Methods: We assessed the dCA values in AIS patients and in healthy controls (n = 10). The AIS patient group consisted of anterior circulation cortical (n = 11) and subcortical (n = 11) strokes within 48 h of symptom onset. Cerebral blood flow velocity was measured using transcranial Doppler ultrasound, and BP measurements were recorded before, during and after the release of bilateral thigh cuffs in 10 controls (7 males) of a mean age of 59 ±15 years (range 31-75), 11 cortical strokes (7 males) of a mean of age 65 ± 19 years (range 25-88) and 11 subcortical strokes (7 males) of a mean age of 60 ± 18 years (range 39-85). Autoregulation index (ARI) estimates, calculated using spontaneous fluctuations and thigh cuff manoeuvre, were derived. Differences in ARI (Tiecks' model) were tested with repeated-measures ANOVA. Results: A total of 22 patients were included, comprising 11 subcortical (lacunar clinical syndrome) and 11 cortical strokes (total anterior circulation stroke/partial anterior circulation syndrome). Of the 10 control subjects, 1 later withdrew because of intolerance to the thigh cuffs. Similar ARI estimates were obtained in both groups, whether assessed from spontaneous fluctuations or thigh cuff measurements (p = 0.37). ARI differences were not significantly different between hemispheres for both control and stroke populations. ARI was significantly impaired in AIS patients compared to age-, sex- and BP-matched control subjects, with a greater impairment of dCA observed in cortical IS. Conclusions: The results of this study suggest that both spontaneous fluctuations and thigh cuff deflation techniques are able to provide reliable estimates of ARI, with the estimates from both spontaneous fluctuations and thigh cuff deflation techniques being in keeping with those reported elsewhere in the literature. dCA was impaired following AIS compared to controls when stroke subtype was considered. Importantly, no differences were observed between UA and AF. This has implications for the assessment of CA after stroke and reinforces the need to define a 'gold standard' test for the investigation of CA. Copyright © 2013 S. Karger AG, Basel.
Clemente S.,Medical Physics, Inc.
Journal of applied clinical medical physics / American College of Medical Physics | Year: 2013
Intensity-modulated radiation therapy (IMRT) has become a standard treatment for prostate cancer based on the superior sparing of the bladder, rectum, and other surrounding normal tissues compared to three-dimensional conformal radiotherapy, despite the longer delivery time and the increased number of monitor units (MU). The novel RapidArc technique represents a further step forward because of the lower number of MUs per fraction and the shorter delivery time, compared to IMRT. This paper refers to MU optimization in RA plans for prostate cancer, using a tool incorporated in Varian TPS Eclipse. The goal was to get the lowest MU RA plan for each patient, keeping a well-defined level of PTV coverage and OAR sparing. Seven prostate RA plans (RA MU-Optimized) were retrospectively generated using the MU optimization tool in Varian Eclipse TPS. Dosimetric outcome and nontarget tissue sparing were, compared to those of RA clinical plans (RA Clinical) used to treat patients. Compared to RA Clinical, RA MU-Optimized plans resulted in an about 28% (p = 0.018) reduction in MU. The total integral dose (ID) to each nontarget tissue (but not the penile bulb) showed a consistent average relative reduction, statistically significant only for the femoral heads. Within the intermediate dose region (40-60 Gy), ID reductions (4%-17% p < 0.05) were found for the rectum, while a slight but significant (0.4%-0.9%, p < 0.05) higher ID was found for the whole body. Among the remaining data, the mean dose to the bladder was also reduced (-12%, p = 0.028). Plans using MU optimization are clinically applicable and more MU efficient, ameliorating the exposure of the rectum and the bladder to intermediate doses.
Battista J.J.,Medical Physics, Inc.
Journal of applied clinical medical physics / American College of Medical Physics | Year: 2012
The January 2010 articles in The New York Times generated intense focus on patient safety in radiation treatment, with physics staffing identified frequently as a critical factor for consistent quality assurance. The purpose of this work is to review our experience with medical physics staffing, and to propose a transparent and flexible staffing algorithm for general use. Guided by documented times required per routine procedure, we have developed a robust algorithm to estimate physics staffing needs according to center-specific workload for medical physicists and associated support staff, in a manner we believe is adaptable to an evolving radiotherapy practice. We calculate requirements for each staffing type based on caseload, equipment inventory, quality assurance, educational programs, and administration. Average per-case staffing ratios were also determined for larger-scale human resource planning and used to model staffing needs for Ontario, Canada over the next 10 years. The workload specific algorithm was tested through a survey of Canadian cancer centers. For center-specific human resource planning, we propose a grid of coefficients addressing specific workload factors for each staff group. For larger scale forecasting of human resource requirements, values of 260, 700, 300, 600, 1200, and 2000 treated cases per full-time equivalent (FTE) were determined for medical physicists, physics assistants, dosimetrists, electronics technologists, mechanical technologists, and information technology specialists, respectively.
Zakaria A.,University of Manitoba |
Gilmore C.,Medical Physics, Inc. |
LoVetri J.,University of Manitoba
Inverse Problems | Year: 2010
With respect to the microwave imaging of the dielectric properties in an imaging region, the full derivation of a new inversion algorithm based on the contrast source inversion (CSI) algorithm and a finite-element method (FEM) discretization of the Helmholtz differential operator formulation for the scattered electromagnetic field is presented. The unknown dielectric properties are represented as nodal values on a two-dimensional (2D) arbitrary triangular mesh using linear basis functions. The use of FEM to represent the Helmholtz operator allows for the flexibility of having an inhomogeneous background medium, as well as the ability to accurately model any boundary shape or type: both conducting and absorbing. The resulting sparse and symmetric FEM matrix equation can be solved efficiently, and it is shown how its solution can be used to calculate the gradient operators required in the conjugate-gradient CSI update without storing the inverse of the FEM matrix. The inversion algorithm is applied to conductive-enclosures of various shapes and unbounded-region microwave tomography configurations where the 2D transverse magnetic (TM) approximation can be applied. © 2010 IOP Publishing Ltd.
Agency: Department of Health and Human Services | Branch: | Program: SBIR | Phase: Phase I | Award Amount: 106.27K | Year: 2010
DESCRIPTION (provided by applicant): Insufficient oxygenation of the blood (hypoxemia) is a common symptom in ICU patients, and may be caused by a combination of four different pathologies: 1) decreased alveolar ventilation (hypoventilation), 2) oxygen diffusion limitation, 3) inequality in ventilation/perfusion, and 4) shunts. Hypoxemia can be assessed by any of the following physiological parameters: 1) arterial PO2 and PCO2, 2) difference in alveolar and arterial PO2, 3) venous admixture (known as a physiological shunt), and 4) physiological dead space. However, while these parameters are clinically useful, they offer quite limited information and are subject to misinterpretation when the underlying assumptions are not met. For the most part, the exact causes of hypoxemia are difficult to distinguish in any given patient using presently available tools. A multiple inert gas elimination technique (MIGET) was introduced in the early 1970s as a way to overcome many of the limitations imposed by the classical methods mentioned above. The uniqueness of MIGET is its use of inert gas data to quantitate the many pathological features of O2 and CO2 gas exchange in the acutely ill. Taking advantage of simpler gas exchange models applied to inert gases (compared to O2 and CO2), MIGET provides quantitative distributions of ventilation and blood flow with respect to Vand / Qand ratio. It is the acquisition of these distributions that form the basis for the many calculations of O2 and CO2 gas exchange parameters that MIGET provides. Importantly, a special strength of MIGET is that it distinguishes regions of low Vand A / Qand ratio from unventilated regions (shunt), and also regions of high Vand A / Qand ratio from unperfused lung. MIGET also allows additional insights into gas exchange, which include 1) identification of the presence of diffusion limitation for O2, and 2) quantification of the role of extrapulmonary factors on arterial PO2 and PCO2 gas exchange limitation. However, MIGET has never evolved from a research tool to a clinical management tool due to: 1) measurement time delays; 2) operational complexity; and 3) substantial invasiveness. The goal of this proposed work is to develop and validate the instrumentation and methodology that provides the complex Vand / Qand distribution and analysis of MIGET - but without the cited disadvantages. PUBLIC HEALTH RELEVANCE: For over 30 years, MIGET (Multiple Inert Gas Elimination Technique) has been a valuable research tool used to understand and characterize lung abnormalities. Physiological information from this technique could greatly improve therapy in the Intensive Care Unit (ICU), but the highly invasive methods make it impractical in any clinical setting. This proposed Non-Invasive MIGET System (NIMS) has the potential to provide MIGET information to improve patient management both in and outside of the ICU.