Abstract：
:The feasibility of using film dosimetry data as the input data for patient treatment planning was evaluated. The central-axis depth dose and the off-axis ratios obtained from film measurements in a solid phantom were compared with those of ion-chamber measurements in water. Two techniques were used to generate isodose distributions. The first technique used only the film data, i.e., the central-axis depth dose and the off-axis ratios used for the reconstruction were determined from the film optical density (corrected for film nonlinearity). In the second technique, the central-axis depth dose measured by an ion chamber in a water phantom was combined with the off-axis ratios measured using film in the "solid water" phantom. The resulting isodose distributions from both techniques were compared with the ion-chamber measurements in water for 7-, 12-, and 18-MeV electrons, and the second technique showed better agreement with the ion-chamber measurements than did the first technique. The differences were within a clinically acceptable range.
journal_name
Med Physjournal_title
Medical physicsauthors
Shiu AS,Otte VA,Hogstrom KRdoi
10.1118/1.596409subject
Has Abstractpub_date
1989-11-01 00:00:00pages
911-5issue
6eissn
0094-2405issn
2473-4209journal_volume
16pub_type
杂志文章相关文献
MEDICAL PHYSICS文献大全abstract：PURPOSE:The thermoluminescence dosimeter (TLD) has desirable features including low cost, reusability, small size, and relatively low energy dependence. However, the commonly available poly-crystal TLDs (e.g., TLD-100) exhibit high interdetector variability that requires individual calibration for high detection accura...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.13895
更新日期：2020-01-01 00:00:00
abstract：:Imaging of radiation dose distribution in gel phantoms by magnetic resonance techniques has previously been reported. In this paper a method of producing gels in which the distributions of radiation dose can also be visualized as a color change is reported. The color developed depends qualitatively and quantitatively ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.596676
更新日期：1991-03-01 00:00:00
abstract：:With the recent clinical implementation of real-time MRI-guided x-ray beam therapy (MRXT), attention is turning to the concept of combining real-time MRI guidance with proton beam therapy; MRI-guided proton beam therapy (MRPT). MRI guidance for proton beam therapy is expected to offer a compelling improvement to the c...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.12371
更新日期：2017-08-01 00:00:00
abstract：PURPOSE:Tissue textures have been recognized as biomarkers for various clinical tasks. In computed tomography (CT) image reconstruction, it is important but challenging to preserve the texture when lowering x-ray exposure from full- toward low-/ultra-low dose level. Therefore, this paper aims to explore the texture-dos...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.14449
更新日期：2020-10-01 00:00:00
abstract：:Soft-tissue detectability in cone-beam computed tomography (CBCT) was evaluated via two-alternative forced-choice (2AFC) tests. Investigations included the dependence of detectability on radiation dose, the influence of the asymmetric three-dimensional (3D) noise-power spectrum (NPS) in axial and sagittal or coronal p...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.2790586
更新日期：2007-11-01 00:00:00
abstract：PURPOSE:A series of examples are presented in which potential errors in the delivery of radiation therapy were prevented through use of incident learning. These examples underscore the value of reporting near miss incidents. METHODS:Using a departmental incident learning system, eight incidents were noted over a two-y...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4760774
更新日期：2012-11-01 00:00:00
abstract：PURPOSE:Radiotherapy, especially with charged particles, is sensitive to executional and preparational uncertainties that propagate to uncertainty in dose and plan quality indicators, for example, dose-volume histograms (DVHs). Current approaches to quantify and mitigate such uncertainties rely on explicitly computed e...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.14414
更新日期：2020-10-01 00:00:00
abstract：PURPOSE:Accurate segmentation of lungs with severe interstitial lung disease (ILD) in thoracic computed tomography (CT) is an important and difficult task in the development of computer-aided diagnosis (CAD) systems. Therefore, we developed in this study a texture analysis-based method for accurate segmentation of lung...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3222872
更新日期：2009-10-01 00:00:00
abstract：:Recently, the clinical application of electronic portal imaging devices has enabled more frequent verification of patient setup for radiation treatment. However, the image quality has sometimes proven to be inadequate, motivating the investigation of alternative sensors with better image quality. Amorphous selenium (a...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.598219
更新日期：1998-04-01 00:00:00
abstract：:Current generation electronic portal imaging devices (EPID) contain a 1.0 mm copper conversion plate to increase detection efficiency of a therapeutic megavoltage spectrum. When using these EPIDs for low-Z target imaging, the conversion plate largely attenuates the large populations of diagnostic energy photons, there...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4740105
更新日期：2012-07-01 00:00:00
abstract：:One of the methods currently being used to treat choroidal melanoma employs an episcleral plaque containing I-125 radioactive seeds. However, comprehensive dosimetry studies on the plaque are scarce and controversial. For this work, we use film to study the dosimetry outside the lip of the gold shield of the eye plaqu...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.596556
更新日期：1990-09-01 00:00:00
abstract：:During our routine calibration of a Varian Clinac-20 linear accelerator, the absorbed dose for a fixed monitor unit (mu) was found to decrease with increasing dose rate. Between dose rates of 100 and 500 mu/min, there was up to 20% difference in absorbed dose for a 20-MeV electron beam. The cause of this problem was a...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.596192
更新日期：1988-09-01 00:00:00
abstract：PURPOSE:Metastatic melanoma lesions experienced marked regression after systemic targeted alpha therapy in a phase 1 clinical trial. This unexpected response was ascribed to tumor antivascular alpha therapy (TAVAT), in which effective tumor regression is achieved by killing endothelial cells (ECs) in tumor capillaries ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3681010
更新日期：2012-03-01 00:00:00
abstract：:In a recent paper of Miller et al. (Med. Phys. 43(5), 2141-2152 (2016), the voltage dependence polarity effect of microionization chambers was studied. It was identified that polarity effect arises from the difference in electric potential between the collecting electrode and the guard electrode, which in turn deforms...
journal_title：Medical physics
pub_type： 信件
doi：10.1002/mp.12019
更新日期：2017-03-01 00:00:00
abstract：PURPOSE:Adding magnetic resonance (MR)-derived information to standard transrectal ultrasound (TRUS) images for guiding prostate biopsy is of substantial clinical interest. A tumor visible on MR images can be projected on ultrasound (US) by using MR-US registration. A common approach is to use surface-based registratio...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4917481
更新日期：2015-05-01 00:00:00
abstract：:For the case of eye tumor therapy with protons, improvements are introduced compared to the standard dose calculation which implies straight-line optics and the constant-density assumption for the eye and its surrounding. The progress consists of (i) taking account of the lateral scattering of the protons in tissue by...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.2168067
更新日期：2006-03-01 00:00:00
abstract：PURPOSE:To commission and benchmark a vendor-supplied (Varian Medical Systems) Monte Carlo phase-space data for the 6 MV flattening filter free (FFF) energy mode on a TrueBeam linear accelerator for the purpose of quality assurance of clinical volumetric modulated arc therapy (VMAT) treatment plans. A method for render...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4773883
更新日期：2013-02-01 00:00:00
abstract：:A computer dose model for a low energy gamma-emitting stent in a heterogeneous medium is described. The method is based on the Sievert model which is adapted to the dose-point-kernel (DPK) model to compute the dose distribution about filtered gamma sources (Sievert-DPK model). The new gamma stent model can take into a...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.1380214
更新日期：2001-07-01 00:00:00
abstract：PURPOSE:Arterial distensibility is a marker that can measure vessel wall functional and structural changes resulting from atherosclerosis with applications including estimation of mechanical properties of the wall. We sought to assess the feasibility of using magnetic resonance imaging (MRI) to include wall distensibil...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4754302
更新日期：2012-10-01 00:00:00
abstract：PURPOSE:Small animal immobilization devices facilitate positioning of animals for reproducible imaging and accurate focal radiation therapy. In this study, the authors demonstrate the use of three-dimensional (3D) printing technology to fabricate a custom-designed mouse head restraint. The authors evaluate the accuracy...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4933200
更新日期：2015-11-01 00:00:00
abstract：:When a beam-modifying filter such as a wedge or a compensator is placed in an x-ray beam, scattered photons are generated in the filter material. The magnitude of the dose contribution from these photons for a 4-MV x-ray beam was measured. At a distance of 30 cm from the filter, a copper sheet of 1-cm thickness produc...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.595923
更新日期：1986-01-01 00:00:00
abstract：PURPOSE:Recent recommendations of the International Commission on Radiological Protection state that the use of effective dose (E) for assessing patient exposure has severe limitations, though it can be kept for dose comparisons. In cardiology procedures, the equivalent dose (H(T)) is one of the most appropriate dose q...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3561508
更新日期：2011-04-01 00:00:00
abstract：PURPOSE:A high resolution, water equivalent, optical and passive x-ray dosimeter has been constructed using plastic scintillator and optical fiber. This dosimeter has a peak edge-on spatial resolution of 100 μm in one dimension, with a 10 μm resolution dosimeter under investigation. The dosimeter design has a potential...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.12209
更新日期：2017-05-01 00:00:00
abstract：:This paper presents a numerical investigation of the effective point of measurement of thimble ionization chambers in megavoltage photon beams using Monte Carlo simulations with the EGSNRC system. It is shown that the effective point of measurement for relative photon beam dosimetry depends on every detail of the cham...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.2201147
更新日期：2006-06-01 00:00:00
abstract：PURPOSE:Recently, brain tumor segmentation has made important progress. However, the quality of manual labels plays an important role in the performance, while in practice, it could vary greatly and in turn could substantially mislead the learning process and decrease the accuracy. We need to design a mechanism to comb...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.14480
更新日期：2020-09-24 00:00:00
abstract：:Surgical guidance with fluorescence has been demonstrated in individual clinical trials for decades, but the scientific and commercial conditions exist today for a dramatic increase in clinical value. In the past decade, increased use of indocyanine green based visualization of vascular flow, biliary function, and tis...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4951732
更新日期：2016-06-01 00:00:00
abstract：PURPOSE:The authors had previously published measurements of the detectability of disk-shaped contrast objects in images obtained from a C-arm CT system. A simple approach based on Rose's criterion was used to scale the date, assuming the threshold for the smallest diameter detected should be inversely proportional to ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3397465
更新日期：2010-05-01 00:00:00
abstract：PURPOSE:The image registration literature comprises many methods for 2D-3D registration for which accuracy has been established in a variety of applications. However, clinical application is limited by a small capture range. Initial offsets outside the capture range of a registration method will not converge to a succe...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3366252
更新日期：2010-04-01 00:00:00
abstract：:In this investigation, five experimental data sets are used to evaluate the ability of the EGSnrc Monte Carlo code to calculate the change in chamber response associated with changes in wall material and cavity dimension at 60Co energies. Calculations of the ratios of response per unit mass of air as a function of cav...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3013701
更新日期：2008-12-01 00:00:00
abstract：BACKGROUND:X-ray dark-field radiography could enhance mammography by providing more information on imaged tissue and microcalcifications. The dark field signal is a measure of small angle scattering and can thus provide additional information on the imaged materials. This information can be useful for material distinct...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.14043
更新日期：2020-04-01 00:00:00
