Abstract：
:The use of the stable isotope 48Ca as a tracer in biological systems has been studied. Determination of 48Ca concentrations in samples was accomplished by proton activation via the (p,n) reaction with subsequent measurement of gamma-ray spectra from 44-h 48Sc and 4-h 44Sc. With protons of about 5.5 MeV and a Ge(Li) gamma-ray detector, and with no chemical processing of the samples, ratios of these two radioisotopes can be determined with sufficient precision to allow 48Ca tracer studies to be performed with sensitivity at least equivalent to that possible with the common 45Ca radioactive tracer.
journal_name
Med Physjournal_title
Medical physicsauthors
Edwards FM,Kraushaar JJ,Ristinen RA,Rudolph Hdoi
10.1118/1.594303subject
Has Abstractpub_date
1977-01-01 00:00:00pages
58-65issue
1eissn
0094-2405issn
2473-4209journal_volume
4pub_type
杂志文章相关文献
MEDICAL PHYSICS文献大全abstract：PURPOSE:To evaluate the image quality of virtual monochromatic images synthesized from dual-source dual-energy computed tomography (CT) in comparison with conventional polychromatic single-energy CT for the same radiation dose. METHODS:In dual-energy CT, besides the material-specific information, one may also synthesi...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3658568
更新日期：2011-12-01 00:00:00
abstract：:A scintillation dosemeter is calibrated for 90Sr/90Y beta rays from an ophthalmic applicator, using an extrapolation ionization chamber as a reference instrument. The calibration factor for the scintillation dosemeter agrees with that given by the manufacturer of the dosemeter within ca. 2%. The estimated overall unce...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.1709490
更新日期：2004-05-01 00:00:00
abstract：:The scattered-photon part of pencil-beam dose kernels for high-energy x-ray beams can be derived experimentally by differentiating the broad-beam scatter-to-primary dose ratio as a function of radius. Formally, this requires a uniform and parallel beam, and the procedure is complicated by the nonideal, actual beam con...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.597884
更新日期：1996-09-01 00:00:00
abstract：PURPOSE:This paper provides a comparison between a fast, commercial, in-patient Monte Carlo dose calculation algorithm (GPUMCD) and geant4. It also evaluates the dosimetric impact of the application of an external 1.5 T magnetic field. METHODS:A stand-alone version of the Elekta™ GPUMCD algorithm, to be used within th...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4939808
更新日期：2016-02-01 00:00:00
abstract：PURPOSE:In this report, the authors introduce the general concept of the completeness map, as a means to evaluate the completeness of data acquired by a given CT system design (architecture and scan mode). They illustrate the utility of completeness map by applying the completeness map concept to a number of candidate ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3700172
更新日期：2012-05-01 00:00:00
abstract：:Current methods for imaging joint motion are limited to either two-dimensional (2D) video fluoroscopy, or to animated motions from a series of static three-dimensional (3D) images. 3D movement patterns can be detected from biplane fluoroscopy images matched with computed tomography images. This involves several x-ray ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.2000647
更新日期：2005-09-01 00:00:00
abstract：:Boron neutron capture therapy (BNCT) is an experimental type of radiotherapy, presently being used to treat glioblastoma and melanoma. To improve patient safety and to determine the radiobiological characteristics of the epithermal neutron beam of Finnish BNCT facility (FiR 1) dose-response studies were carried on the...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.1517048
更新日期：2002-11-01 00:00:00
abstract：:In order to use negative pions for the treatment of large deep-seated tumors in radiotherapy, it is necessary to produce depth-dose distributions tailored to specific shapes. We present here a method of beam shaping which utilizes a fluid-filled piston having a programmable, computer-controlled, time-dependent thickne...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.594313
更新日期：1977-09-01 00:00:00
abstract：PURPOSE:4d cone-beam computed tomography (CBCT) scans are usually reconstructed by extracting the motion information from the 2d projections or an external surrogate signal, and binning the individual projections into multiple respiratory phases. In this "after-the-fact" binning approach, however, projections are uneve...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4817479
更新日期：2013-09-01 00:00:00
abstract：PURPOSE:Quantitative SPECT imaging is limited by many factors, including penetration of high energy photons through the collimator. Even small peaks of high energy yield extensive contamination in the photopeak energy window. Rotating slat collimators typically offer a 40- to 50-fold increase in geometric detection eff...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3177312
更新日期：2009-09-01 00:00:00
abstract：PURPOSE:Intracavitary accelerated partial breast irradiation (APBI) has become a popular treatment for early stage breast cancer in recent years due to its shortened course of treatment and simplified treatment planning compared to traditional external beam breast conservation therapy. However, the exit dose to the ski...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3429089
更新日期：2010-06-01 00:00:00
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
pub_type： 杂志文章
doi：10.1118/1.4868455
更新日期：2014-04-01 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
pub_type： 杂志文章
doi：10.1118/1.4735033
更新日期：2012-06-01 00:00:00
abstract：PURPOSE:Several works have recently focused on flattening-filter-free (FFF) beams of linear accelerators of various companies (in particular, Varian and Elekta), but no overview as yet exists for the flattening-filter free 7XU beam (Siemens Artiste). METHODS:Dosimetric properties of the 7XU beam were measured in May a...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3703835
更新日期：2012-05-01 00:00:00
abstract：PURPOSE:To construct a Monte Carlo (MC)-based simulation model for analyzing the dependence of tumor oxygen distribution on different variables related to tumor vasculature [blood velocity, vessel-to-vessel proximity (vessel proximity), and inflowing oxygen partial pressure (pO2)]. METHODS:A voxel-based tissue model c...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4892386
更新日期：2014-09-01 00:00:00
abstract：PURPOSE:In order to build up a reliable dose monitoring system for boron neutron capture therapy (BNCT) applications at the TRIGA reactor in Mainz, a computer model for the entire reactor was established, simulating the radiation field by means of the Monte Carlo method. The impact of different source definition techni...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4897242
更新日期：2014-11-01 00:00:00
abstract：:Computed tomography colonography (CTC) is a minimally invasive method that allows the evaluation of the colon wall from CT sections of the abdomen/pelvis. The primary goal of CTC is to detect colonic polyps, precursors to colorectal cancer. Because imperfect cleansing and distension can cause portions of the colon wal...
journal_title：Medical physics
pub_type： 临床试验,杂志文章
doi：10.1118/1.1796171
更新日期：2004-10-01 00:00:00
abstract：:A modified neutron production target assembly has been developed to provide improved performance of the proton-cyclotron-based neutron radiotherapy facility at the University of Washington for applications involving neutron capture enhanced fast-neutron therapy. The new target produces a neutron beam that yields essen...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.598839
更新日期：2000-02-01 00:00:00
abstract：:A commercially available open MRI unit is under routine use for radiation therapy simulation. The effects of a gradient distortion correction (GDC) program used to post process the images were assessed by comparison with the known geometry of a phantom. The GDC reduced the magnitude of the distortions at the periphery...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.1513991
更新日期：2002-11-01 00:00:00
abstract：:In this study we address the problem of predicting the position of a moving lung tumor during respiration on the basis of external breathing signals--a technique used for beam gating, tracking, and other dynamic motion management techniques in radiation therapy. We demonstrate the use of neural network filters to corr...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.2134958
更新日期：2005-12-01 00:00:00
abstract：PURPOSE:Radiochromic film provides dose measurement at high spatial resolution, but often is not preferred for routine evaluation of patient-specific intensity modulated radiation therapy (IMRT) plans owing to ease-of-use factors. The authors have established an efficient protocol that combines calibration and measurem...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4754797
更新日期：2012-10-01 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
pub_type： 杂志文章
doi：10.1118/1.597209
更新日期：1994-08-01 00:00:00
abstract：PURPOSE:The purpose of this study was to detect and analyze anomalies between a large number of computed tomography (CT) scanners, tracked over time, utilized to collect human pulmonary CT data for a national multicenter study: chronic obstructive pulmonary disease genetic epidemiology study (COPDGene). METHODS:A cust...
journal_title：Medical physics
pub_type： 杂志文章,多中心研究
doi：10.1118/1.4747342
更新日期：2012-09-01 00:00:00
abstract：PURPOSE:The purpose of this study was to quantitatively characterize the fundamental aspects of image quality (IQ) associated with different computed tomography (CT) reconstruction algorithms, the resolution, noise texture, noise magnitude per dose, and use those data to devise a methodology to match IQ between differe...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.12554
更新日期：2017-11-01 00:00:00
abstract：:Anatomy-based positron emission tomography (PET) image enhancement techniques have been shown to have the potential for improving PET image quality. However, these techniques assume an accurate alignment between the anatomical and the functional images, which is not always valid when imaging the chest due to respirato...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.2804721
更新日期：2007-12-01 00:00:00
abstract：PURPOSE:To determine the accuracy and test-retest repeatability of fast radiofrequency (RF) transmit measurement approaches used in Dynamic Contrast Enhanced Magnetic Resonance Imaging (DCE-MRI). Spatial variation in the transmitted RF field introduces bias and increased variance in quantitative DCE-MRI metrics includi...
journal_title：Medical physics
pub_type： 杂志文章,多中心研究
doi：10.1002/mp.13518
更新日期：2019-06-01 00:00:00
abstract：PURPOSE:A multi-institution dosimetry intercomparison has been undertaken of prostate intensity modulated radiation therapy (IMRT) delivery. The dosimetry intercomparison was incorporated into the quality assurance for site credentialing for the Trans-Tasman Radiation Oncology Group Prostate Fractionated Irradiation Tr...
journal_title：Medical physics
pub_type： 临床试验,杂志文章,多中心研究
doi：10.1118/1.4808151
更新日期：2013-07-01 00:00:00
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
pub_type： 杂志文章
doi：10.1118/1.2775667
更新日期：2007-10-01 00:00:00
abstract：PURPOSE:The measurement of malignant pleural mesothelioma is critical to the assessment of tumor response to therapy. Current response assessment standards utilize summed linear measurements acquired on three computed tomography (CT) sections. The purpose of this study was to evaluate manual area measurements as an alt...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4810940
更新日期：2013-08-01 00:00:00
abstract：PURPOSE:Until recently the treatment verification for patients undergoing fast neutron therapy at our facility was accomplished through a combination of neutron beam portal films aligned with a graticule mounted on an orthronormal x-ray tube. To eliminate uncertainty with respect to the relative positions of the x-ray ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4734951
更新日期：2012-06-01 00:00:00
