The collapsed cone superposition algorithm applied to scatter dose calculations in brachytherapy.

abstract：PURPOSE:Cone-beam computed tomography (CBCT) is an increasingly utilized imaging modality for the diagnosis and treatment planning of the patients with craniomaxillofacial (CMF) deformities. Accurate segmentation of CBCT image is an essential step to generate three-dimensional (3D) models for the diagnosis and treatmen...

journal_title：Medical physics

authors： Wang L,Chen KC,Gao Y,Shi F,Liao S,Li G,Shen SG,Yan J,Lee PK,Chow B,Liu NX,Xia JJ,Shen D

更新日期：2014-04-01 00:00:00

abstract：PURPOSE:The purpose of this study is to investigate whether the microvascular pseudodiffusion effects resulting with non-monoexponential behavior are present in breast cancer, taking into account tumor spatial heterogeneity. Additionally, methodological factors affecting the signal in low and high diffusion-sensitizing...

journal_title：Medical physics

authors： Panek R,Borri M,Orton M,O'Flynn E,Morgan V,Giles SL,deSouza N,Leach MO,Schmidt MA

更新日期：2015-08-01 00:00:00

abstract：PURPOSE:An optimized air ventilation system design for a treatment room in Heavy-ion Medical Facility is an important issue in the aspects of nuclear safety because the activated air produced in a treatment room can directly affect the medical staff and the general public in the radiation-free area. METHODS:Optimized ...

journal_title：Medical physics

authors： Kum O

更新日期：2018-06-01 00:00:00

abstract：:To more accurately and precisely delineate a tumor in a 3D PET image, we proposed a novel, semi-automatic, two-stage method by utilizing an adaptive region-growing algorithm and a dual-front active contour model. First, a rough region of interest (ROI) is manually drawn by a radiation oncologist that encloses a tumor....

journal_title：Medical physics

authors： Li H,Thorstad WL,Biehl KJ,Laforest R,Su Y,Shoghi KI,Donnelly ED,Low DA,Lu W

更新日期：2008-08-01 00:00:00

abstract：:Imaging parameters associated with a clinical magnetic resonance imaging (MRI) system, evaluated with the use of simple and inexpensive phantoms, are described in evaluation of a clinical MRI system. Images, obtained with a Diasonics 0.35-T MRI system using an elliptical whole-body radio frequency coil, are presented ...

journal_title：Medical physics

authors： Brateman L,Jennings LW,Nunnally RL,Vaughan JT

更新日期：1986-07-01 00:00:00

abstract：:Measurements of a 670-MeV/amu 20Ne beam at the Lawrence Berkeley Laboratory Bevalac heavy-ion accelerator with various thicknesses of water absorber were obtained with the BERKLET. The BERKLET, a simple three-stage solid-state telescope detector, has been described previously. This instrument measures the linear energ...

journal_title：Medical physics

authors： Llacer J,Schmidt JB,Tobias CA

更新日期：1990-03-01 00:00:00

abstract：PURPOSE:To Validate Brainlab-ExacTrac IGRT with Dot-Decimal electron compensator(BolusECT) for accurate patient positioning. METHODS:Dot-Decimal electron compensators(BolusECT) are used to achieve conformal dose distributions and greater sparing to normal structures for cases with varying patient contours and treated ...

journal_title：Medical physics

authors： Prabhu A,Saini D,Patadiya B,Shankar R,Garthwaite T

更新日期：2012-06-01 00:00:00

abstract：:Molecular imaging is the direct or indirect noninvasive monitoring and recording of the spatial and temporal distribution of in vivo molecular, genetic, and/or cellular processes for biochemical, biological, diagnostic, or therapeutic applications. Molecular images that indicate the presence of malignancy can be acqui...

journal_title：Medical physics

authors： Munley MT,Kagadis GC,McGee KP,Kirov AS,Jang S,Mutic S,Jeraj R,Xing L,Bourland JD

更新日期：2013-10-01 00:00:00

abstract：:Currently, patients with brain neoplasms must undergo both computed tomography (CT) and magnetic resonance (MR) imaging to take advantage of CT's density information and MR's soft tissue imaging capabilities. A method has been developed that allows virtual simulation, digitally reconstructed radiographs (DRRs), and 3-...

journal_title：Medical physics

authors： Ramsey CR,Oliver AL

更新日期：1998-10-01 00:00:00

abstract：:Plaque rupture with superimposed thrombosis is the main cause of the acute coronary syndromes of unstable angina, myocardial infarction, and sudden death. Endothelial disruption leading to plaque rupture may relate to mechanical fatigue associated with cyclic flexion of plaques. A novel method is proposed to assess st...

journal_title：Medical physics

authors： Wu HC,Chen SY,Shroff SG,Carroll JD

更新日期：2003-11-01 00:00:00

abstract：PURPOSE:The absolute dose rate of the Imaging and Medical Beamline (IMBL) on the Australian Synchrotron was measured with a graphite calorimeter. The calorimetry results were compared to measurements from the existing free-air chamber, to provide a robust determination of the absolute dose in the synchrotron beam and p...

journal_title：Medical physics

authors： Harty PD,Lye JE,Ramanathan G,Butler DJ,Hall CJ,Stevenson AW,Johnston PN

更新日期：2014-05-01 00:00:00

abstract：PURPOSE:Computed tomography (CT) and, in particular, cone beam CT (CBCT) have been increasingly used as a diagnostic tool in recent years. Patient motion during acquisition is common in CBCT due to long scan times. This results in degraded image quality and may potentially increase the number of retakes. Our aim was to...

journal_title：Medical physics

authors： Niebler S,Schömer E,Tjaden H,Schwanecke U,Schulze R

更新日期：2019-10-01 00:00:00

abstract：:A method for optimizing MR imaging pulse sequence parameters in a statistical framework is presented. Parameters are defined to be optimal when the resulting scalar images yield optimal image segmentations using Bayesian pixel classification. Thus, Bayes risk is used as the objective function to minimize. Approximatio...

journal_title：Medical physics

authors： Prince JL,Pham D,Tan O

更新日期：1995-10-01 00:00:00

abstract：:The commonly used Blunck and Leisegang electron energy-loss distribution falls off too rapidly with increasing energy loss. Also, for large thicknesses and/or low-Z media, where their distribution should approach Landau's, it normalizes to 0.92 rather than 1.0, it overestimates the number of very small energy-loss eve...

journal_title：Medical physics

authors： Weinhous MS,Nath R

更新日期：1984-05-01 00:00:00

abstract：:Studies suggest that clinical outcomes are improved in repeat trigeminal neuralgia (TN) Gamma Knife radiosurgery if a different part of the nerve from the previous radiosurgery is treated. The MR images taken in the first and repeat radiosurgery need to be coregistered to map the first radiosurgery volume onto the sec...

journal_title：Medical physics

authors： Li X,Zhang P,Brisman R,Kutcher G

更新日期：2005-07-01 00:00:00

abstract：PURPOSE:In radiotherapy (RT) based on magnetic resonance imaging (MRI) as the only modality, the information on electron density must be derived from the MRI scan by creating a so-called pseudo computed tomography (pCT). This is a nontrivial task, since the voxel-intensities in an MRI scan are not uniquely related to e...

journal_title：Medical physics

authors： Andreasen D,Van Leemput K,Hansen RH,Andersen JA,Edmund JM

更新日期：2015-04-01 00:00:00

abstract：PURPOSE:In this work the performance of a compact multiresolution and multicontrast x-ray phase system based on edge illumination is investigated. It has been designed for small animal imaging and with a limited footprint for ease of deployment in laboratories. METHODS:The presented edge illumination system is based o...

journal_title：Medical physics

authors： Massimi L,Meganck JA,Towns R,Olivo A,Endrizzi M

更新日期：2020-10-27 00:00:00

abstract：PURPOSE:Planning for the delivery of intensity-modulated radiation therapy (IMRT) to a moving target, referred to as four-dimensional (4D) IMRT planning, is a crucial step for achieving the treatment objectives for sites that move during treatment delivery. The authors proposed a simplistic method that accounts for bot...

journal_title：Medical physics

authors： Gui M,Feng Y,Yi B,Dhople AA,Yu C

更新日期：2010-05-01 00:00:00

abstract：PURPOSE/OBJECTIVE:Couch and MLC tracking are two novel techniques to mitigate intrafractional tumor motion on a conventional linear accelerator, but both techniques still have residual dosimetric errors. Here, we first propose and experimentally validate a software tool to simulate couch and MLC tracking, and then use ...

journal_title：Medical physics

authors： Toftegaard J,Hansen R,Ravkilde T,Macek K,Poulsen PR

更新日期：2017-03-01 00:00:00

abstract：:An indirect flat-panel imager (FPI) with avalanche gain is being investigated for low-dose x-ray imaging. It is made by optically coupling a structured x-ray scintillator CsI(Tl) to an amorphous selenium (a-Se) avalanche photoconductor called HARP (high-gain avalanche rushing photoconductor). The final electronic imag...

journal_title：Medical physics

authors： Zhao W,Li D,Reznik A,Lui BJ,Hunt DC,Rowlands JA,Ohkawa Y,Tanioka K

更新日期：2005-09-01 00:00:00

abstract：:The purpose of this work is to demonstrate a proof of feasibility of the application of a commercial prototype deformable model algorithm to the problem of delineation of anatomic structures on four-dimensional (4D) computed tomography (CT) image data sets. We acquired a 4D CT image data set of a patient's thorax that...

journal_title：Medical physics

authors： Ragan D,Starkschall G,McNutt T,Kaus M,Guerrero T,Stevens CW

更新日期：2005-07-01 00:00:00

abstract：:Gd2O2S phosphor screens between 250 and 1000 mg/cm2 thick were evaluated for use in megavoltage imaging systems. The phosphor layers were placed on brass plates ranging from 1 to 5 mm thick, each with and without an optical back reflector (white paint). Light output and spatial resolution were measured at 6- and 23-MV...

journal_title：Medical physics

authors： Wowk B,Shalev S

更新日期：1994-08-01 00:00:00

abstract：:The purpose of this study is to understand the effect of pitch on raw data interpolation in multislice spiral/helical computed tomography (CT) and provide guidelines for scanner design and protocol optimization. Multislice spiral CT is mainly characterized by the three parameters: the number of detector arrays, the de...

journal_title：Medical physics

authors： Wang G,Vannier MW

更新日期：1999-12-01 00:00:00

abstract：PURPOSE:Total and regional body composition are important indicators of health and mortality risk, but their measurement is usually restricted to controlled environments in clinical settings with expensive and specialized equipment. A method that approaches the accuracy of the current gold standard method, dual-energy ...

journal_title：Medical physics

authors： Tian IY,Ng BK,Wong MC,Kennedy S,Hwaung P,Kelly N,Liu E,Garber AK,Curless B,Heymsfield SB,Shepherd JA

更新日期：2020-12-01 00:00:00

abstract：:A beam intensity monitor was tested in a 230-MeV proton beam at the Loma Linda Proton Therapy Accelerator during its commissioning at Fermi National Accelerator Laboratory. The intensity monitor was designed to regulate the beam intensity extracted from the proton synchrotron. The proton beam is tunable between 70 and...

journal_title：Medical physics

authors： Coutrakon G,Miller D,Kross BJ,Anderson DF,DeLuca P Jr,Siebers J

更新日期：1991-07-01 00:00:00

abstract：:Machine outputs, peak scatter factors, and central axis percentage depth dose distributions were measured for various phantom sizes in large radiation fields produced at extended distances by cobalt, 6-MV, and 10-MV photon beams. The results can be applied to practical total body irradiation procedures which usually i...

journal_title：Medical physics

authors： Podgorsak EB,Pla C,Evans MD,Pla M

更新日期：1985-09-01 00:00:00

abstract：PURPOSE:Two-dimensional ultrasound (2D US) imaging is commonly used for diagnostic and intraoperative guidance of interventional liver procedures; however, 2D US lacks volumetric information that may benefit interventional procedures. Over the past decade, three-dimensional ultrasound (3D US) has been developed to prov...

journal_title：Medical physics

authors： Neshat H,Cool DW,Barker K,Gardi L,Kakani N,Fenster A

更新日期：2013-11-01 00:00:00

abstract：:The nucletron Leipzig applicator is designed for (HDR) 192Ir brachy radiotherapy of surface lesions. The dosimetric characteristics of this applicator were investigated using simulation method based on Monte Carlo N-particle (MCNP) code and phantom measurements. The simulation method was validated by comparing calcula...

journal_title：Medical physics

authors： Niu H,Hsi WC,Chu JC,Kirk MC,Kouwenhoven E

更新日期：2004-12-01 00:00:00

abstract：PURPOSE:To present a system for robotic 4D ultrasound (US) imaging concurrent with radiotherapy beam delivery and estimate the proportion of liver stereotactic ablative body radiotherapy (SABR) cases in which robotic US image guidance can be deployed without interfering with clinically used VMAT beam configurations. M...

journal_title：Medical physics

authors： Schlosser J,Gong RH,Bruder R,Schweikard A,Jang S,Henrie J,Kamaya A,Koong A,Chang DT,Hristov D

更新日期：2016-11-01 00:00:00

abstract：PURPOSE:To analyze the noise performance of the edge illumination phase-based x-ray imaging technique when applying "single-shot" phase retrieval. The latter consists in applying a sample-specific low-pass filter to the raw data, leading to "hybrid" images in which phase and attenuation contrast are merged with each ot...

journal_title：Medical physics

authors： Hagen CK,Roche I Morgó O,Olivo A

更新日期：2020-09-01 00:00:00