Monte Carlo dosimetry for I125 and Pd103 eye plaque brachytherapy.

abstract：:Radiographic image guidance has emerged as the new paradigm for patient positioning, target localization, and external beam alignment in radiotherapy. Although widely varied in modality and method, all radiographic guidance techniques have one thing in common--they can give a significant radiation dose to the patient....

journal_title：Medical physics

authors： Murphy MJ,Balter J,Balter S,BenComo JA Jr,Das IJ,Jiang SB,Ma CM,Olivera GH,Rodebaugh RF,Ruchala KJ,Shirato H,Yin FF

更新日期：2007-10-01 00:00:00

abstract：PURPOSE:Radiation Therapy (RT) induced pulmonary function change may depend on the location, underlying function of that lung prior to radiations, radiation dose/fractionation and other factors. We propose to evaluate the radiation induced pulmonary function change using static breath-hold MRI scans with vascular infor...

journal_title：Medical physics

authors： Ding K,Cao K,Du K,Chen Q,Ennis D,Christensen G,Reinhardt J,Libby B,Benedict S,Sheng K

更新日期：2012-06-01 00:00:00

abstract：PURPOSE:The simultaneous measurement of PET and magnetic resonance imaging (MRI) is an emerging field for molecular imaging research. Although optical fiber based PET∕MRI systems have advantages on less interference between PET and MRI, there is a drawback in reducing the scintillation light due to the fiber. To reduce...

journal_title：Medical physics

authors： Yamamoto S,Watabe H,Kanai Y,Watabe T,Aoki M,Sugiyama E,Kato K,Hatazawa J

更新日期：2012-11-01 00:00:00

abstract：:Transthoracic electrical impedance Z consists of a constant baseline component Z0 and the time variable component delta Z such that Z = Z0 + delta Z. The first time derivative of Z has a negative peak, the magnitude of which is (dZ/dt)min. Measurements of 170 volunteers show that (dZ/dt)min is a function of the consta...

journal_title：Medical physics

authors： Djordjevich L,Sadove MS

更新日期：1981-01-01 00:00:00

abstract：PURPOSE:To investigate the geometry dependence of the detector response function (DRF) of three commonly used scanning ionization chambers and its impact on a convolution-based method to address the volume averaging effect (VAE). METHODS:A convolution-based approach has been proposed recently to address the ionization...

journal_title：Medical physics

authors： Barraclough B,Li JG,Lebron S,Fan Q,Liu C,Yan G

更新日期：2016-05-01 00:00:00

abstract：:In Monte Carlo simulations of light transport in tissues, a grid system is set up to score physical quantities. This study of cylindrically symmetrical problems found that the optimized radial and angular positions for the averaged physical quantities in each grid element are off-center. The error of the extrapolated ...

journal_title：Medical physics

authors： Wang L,Jacques SL

更新日期：1994-07-01 00:00:00

abstract：PURPOSE:The Nakagami statistical model and Nakagami shape parameter m have been widely used in linear tissue characterization and preliminarily characterized the envelope distributions of nonlinear encapsulated microbubbles (EMBs). However, the Nakagami distribution of nonlinear scattering EMBs lacked a systematical in...

journal_title：Medical physics

authors： Wang D,Sang Y,Zhang X,Hu H,Lu S,Zhang Y,Fu C,Cloutier G,Wan M

更新日期：2019-12-01 00:00:00

abstract：PURPOSE:Osteoporosis is a common bone disease associated with increased risk of low-trauma fractures leading to substantial morbidity, mortality, and financial costs. Clinically, osteoporosis is defined by low bone mineral density (BMD); however, increasing evidence suggests that trabecular bone (TB) microarchitectural...

journal_title：Medical physics

authors： Saha PK,Liu Y,Chen C,Jin D,Letuchy EM,Xu Z,Amelon RE,Burns TL,Torner JC,Levy SM,Calarge CA

更新日期：2015-09-01 00:00:00

abstract：PURPOSE:To develop a new design of an x-ray beam shaper for helical computed tomography (CT) that increases the dose utilization. METHODS:For typical reconstruction algorithms in helical CT, different data are utilized with different weights during back-projection. In particular, data of the outer detector rows, i.e.,...

journal_title：Medical physics

authors： Köhler T,Brendel B,Proksa R

更新日期：2011-07-01 00:00:00

abstract：:Deionized water is commonly used to couple microwave applicators to the patient surface in the administration of local hyperthermia. Profiles of the specific absorption rate (SAR) at 1-cm depth show that deionized water coupling significantly distorts the SAR distributions of the Clini-Therm 915-MHz 10 X 10 and 15 X 1...

journal_title：Medical physics

authors： Waterman FM,Nerlinger RE

更新日期：1986-05-01 00:00:00

abstract：:Recent work has shown that there is significant uncertainty in measuring build-up doses in mega-voltage photon beams especially at high energies. In this present investigation we used a phantom-embedded extrapolation chamber (PEEC) made of Solid Water to validate Monte Carlo (MC)-calculated doses in the dose build-up ...

journal_title：Medical physics

authors： Abdel-Rahman W,Seuntjens JP,Verhaegen F,Deblois F,Podgorsak EB

更新日期：2005-01-01 00:00:00

abstract：PURPOSE:The small number of samples available for training and testing is often the limiting factor in finding the most effective features and designing an optimal computer-aided diagnosis (CAD) system. Training on a limited set of samples introduces bias and variance in the performance of a CAD system relative to that...

journal_title：Medical physics

authors： Way TW,Sahiner B,Hadjiiski LM,Chan HP

更新日期：2010-02-01 00:00:00

abstract：PURPOSE:The electronic portal imaging device (EPID) is a system for checking the patient setup; as a result of its integration with the linear accelerator and software customized for dosimetry, it is increasingly used for verification of the delivery of fixed-field intensity-modulated radiation therapy (IMRT). In order...

journal_title：Medical physics

authors： Iori M,Cagni E,Paiusco M,Munro P,Nahum AE

更新日期：2010-01-01 00:00:00

abstract：:Radiographic magnification is often employed in mammography to improve detection of small anatomical details of clinical interest, such as microcalcifications. The image size depends on the conventional magnification factor, on the focal spot size, and on the x-ray angulation. In this paper magnification effects are i...

journal_title：Medical physics

authors： Schiabel H,Ventura A,Frère AF

更新日期：1994-02-01 00:00:00

abstract：:The wall of an ionization chamber is commonly assumed to have a negligible effect on chamber response in electron beams. For cylindrical chambers with thin walls this assumption is valid. However, parallel-plate chambers commonly possess large mechanical supports which may affect chamber response in a manner not accou...

journal_title：Medical physics

authors： Hunt MA,Kutcher GJ,Buffa A

更新日期：1988-01-01 00:00:00

abstract：PURPOSE:The most common material for shielding is concrete, which can be made using various materials of different densities as aggregates. New techniques in radiotherapy, as IMRT and VMAT, require more monitor units and it is important to develop specifically designed shielding materials. METHODS:Arraela S.L. has dev...

journal_title：Medical physics

authors： Mera M,Pereira L,Mera M,Pereira L,Meilán E,Moral FD,Teijeiro A,Salgado M,Andrade B,Gomez F,Fuentes-Vázquez V,Caruncho J,Medina A

更新日期：2012-06-01 00:00:00

abstract：PURPOSE:Dual-energy computed tomography and dual-energy cone-beam computed tomography (DE-CBCT) are promising modalities for applications ranging from vascular to breast, renal, hepatic, and musculoskeletal imaging. Accordingly, the optimization of imaging techniques for such applications would benefit significantly fr...

journal_title：Medical physics

authors： Gang GJ,Zbijewski W,Webster Stayman J,Siewerdsen JH

更新日期：2012-08-01 00:00:00

abstract：:We compare the results of absorbed dose determined at reference conditions according to the AAPM TG-21 dose calibration protocol and the new AAPM TG-51 protocol. The AAPM TG-21 protocol for absorbed dose calibration is based on ionization chambers having exposure calibration factors for 60Co gamma rays, N(x). The new ...

journal_title：Medical physics

authors： Ding GX,Cygler JE,Kwok CB

更新日期：2000-06-01 00:00:00

abstract：:Two recently developed A 150 plastic-equivalent gas mixtures have been tested for suitability in proportional counter applications. Methane- and propane-based "tissue-equivalent" gases were also included for comparison purposes. Event-size weighted dose distributions were measured in a 14.8-MeV neutron beam. Resolutio...

journal_title：Medical physics

authors： DeLuca PM Jr,Schell MC,Pearson DW,Higgins PD,Attix FH

更新日期：1984-07-01 00:00:00

abstract：:In prostate seed implants, radioactive seeds are implanted into the prostate through a guiding needle with the help of a template and real-time imaging. The ideal locations of the guiding needles and the relative positions of the seeds in each needle are determined before the implantation under the assumption that the...

journal_title：Medical physics

authors： Nath S,Chen Z,Yue N,Trumpore S,Peschel R

更新日期：2000-05-01 00:00:00

abstract：:In previous work it has been shown that a standard backpropagation neural network can be trained to reconstruct sections of single photon emission computed tomography (SPECT) images based on the planar image projections as inputs. In this study, it is demonstrated that an artificial neural network (ANN) trained on a s...

journal_title：Medical physics

authors： Kerr JP,Bartlett EB

更新日期：1995-05-01 00:00:00

abstract：:Monte Carlo (MC) simulations were performed to estimate brachytherapy dose distributions for Collaborative Ocular Melanoma Study (COMS) eye plaques. Brachytherapy seed models 200, 6711, and CS-1 Rev2 carrying 103Pd, 125I, and 131Cs radionuclides, respectively, were modeled and benchmarked against previously published ...

journal_title：Medical physics

authors： Melhus CS,Rivard MJ

更新日期：2008-07-01 00:00:00

abstract：PURPOSE:Repeated brain MRI scans are performed in many clinical scenarios, such as follow up of patients with tumors and therapy response assessment. In this paper, the authors show an approach to utilize former scans of the patient for the acceleration of repeated MRI scans. METHODS:The proposed approach utilizes the...

journal_title：Medical physics

authors： Weizman L,Eldar YC,Ben Bashat D

更新日期：2015-09-01 00:00:00

abstract：PURPOSE:Stationary computed tomography (s-CT) conceptually offers several advantages over existing rotating gantry-based CT. Over the last 40 yr, s-CT has been investigated using different technological approaches. We are developing a s-CT system specifically for head/brain imaging using carbon nanotube (CNT)-based fie...

journal_title：Medical physics

authors： Spronk D,Luo Y,Inscoe CR,Lee YZ,Lu J,Zhou O

更新日期：2020-12-31 00:00:00

abstract：PURPOSE:To evaluate the dose distribution of a 120-MeV laser-plasma accelerated electron beam which may be of potential interest for high-energy electron radiation therapy. METHODS:In the interaction between an intense laser pulse and a helium gas jet, a well collimated electron beam with very high energy is produced....

journal_title：Medical physics

authors： Lundh O,Rechatin C,Faure J,Ben-Ismaïl A,Lim J,De Wagter C,De Neve W,Malka V

更新日期：2012-06-01 00:00:00

abstract：:The Gafchromic EBT was recently introduced in film dosimetry for external beam therapy (EBT). The high spatial resolution, weak energy dependence, and near-tissue equivalence of EBT films make them suitable for measurement of dose distributions in radiotherapy, especially intensity-modulated radiation therapy (IMRT). ...

journal_title：Medical physics

authors： Fiandra C,Ricardi U,Ragona R,Anglesio S,Giglioli FR,Calamia E,Lucio F

更新日期：2006-11-01 00:00:00

abstract：PURPOSE:Low-dose CT has attracted increasing attention due to growing concerns about radiation exposure in medical scans. However, the frugal use of x-ray radiation inevitably reduces the quality of the CT images, introducing artifacts such as noise and streaks which make the reconstructed images difficult to read in c...

journal_title：Medical physics

authors： Xu W,Mueller K

更新日期：2012-08-01 00:00:00

abstract：PURPOSE:Different approaches have been used in dynamic elastography to assess mechanical properties of biological tissues. Most techniques are based on a simple inversion based on the measurement of the shear wave speed to assess elasticity, whereas some recent strategies use more elaborated analytical or finite elemen...

journal_title：Medical physics

authors： Ouared A,Kazemirad S,Montagnon E,Cloutier G

更新日期：2016-04-01 00:00:00

abstract：:We applied Monte Carlo methods for the simulation of x-ray scattering in water phantoms. The phantom thickness was varied from 5 to 20 cm, and the monoenergetic incident x rays were varied from 15 to 100 keV. Eight screen pairs and a total absorption system were used as x-ray receptors. We determined the angular, spec...

journal_title：Medical physics

authors： Chan HP,Doi K

更新日期：1985-03-01 00:00:00

abstract：PURPOSE:Different low-signal correction (LSC) methods have been shown to efficiently reduce noise streaks and noise level in CT to provide acceptable images at low-radiation dose levels. These methods usually result in CT images with highly shift-variant and anisotropic spatial resolution and noise, which makes the par...

journal_title：Medical physics

authors： Gomez-Cardona D,Hayes JW,Zhang R,Li K,Cruz-Bastida JP,Chen GH

更新日期：2018-05-01 00:00:00