Abstract：
:DICOM format is the de facto standard for communications between therapeutic and diagnostic modalities. A plan generated by a treatment planning system (TPS) is often exported to DICOM format. BEAMnrc/DOSXYZnrc is a widely used Monte Carlo (MC) package for beam and dose simulations in radiotherapy. It has its own definition for beam orientation, which is not in compliance with the one defined in DICOM standard. Dose simulations using TPS generated plans require transformation of beam orientations to DOSXYZnrc coordinate system (c.s.) after extracting the necessary parameters from DICOM RP files. The transformation is nontrivial. There have been two studies for the coordinate transformations. The transformation equation sets derived have been helpful to BEAMnrc/DOSXYZnrc users. However, both the transformation equation sets are complex mathematically and not easy to program. In this study, we derive a new set of transformation equations, which are more compact, better understandable, and easier for computational implementation. The derivation of polar angle θ and azimuthal angle φ is similar to the existing studies by applying a series of rotations to a vector in DICOM patient c.s. The derivation of beam rotation Φcol for DOSXYZnrc, however, is different. It is obtained by a direct combination of the actual collimator rotation with the projection of the couch rotation to the collimator rotating plane. Verification of the transformation has been performed using clinical plans created with Eclipse. The comparison between Eclipse and MC results show exact geometrical agreement for field placements, together with good agreement in dose distributions.
journal_name
Med Physjournal_title
Medical physicsauthors
Zhan L,Jiang R,Osei EKdoi
10.1118/1.4740186subject
Has Abstractpub_date
2012-07-01 00:00:00pages
4639-4640issue
7Part4eissn
0094-2405issn
2473-4209journal_volume
39pub_type
杂志文章相关文献
MEDICAL PHYSICS文献大全abstract：PURPOSE:The present study was conducted to investigate salivary iodine kinetics and dosimetry during repeated courses of radioiodine ((131)I) therapy for differentiated thyroid cancer (DTC). Such data could provide a better understanding of the mechanisms of (131)I induced salivary toxicity and help to develop appropri...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3602459
更新日期：2011-10-01 00:00:00
abstract：:Quantitative evaluation of cardiac image data obtained using multidetector row computed tomography (CT) is compromised by partial scan reconstructions, which improve the temporal resolution but significantly increase image-to-image CT number variations for a fixed region of interest compared to full reconstruction ima...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.2805476
更新日期：2007-12-01 00:00:00
abstract：:The head-scatter factors H were examined for four different linear accelerators and were found to be similar at field sizes larger than 3 x 3 cm2. Sharply reduced values for small collimator openings were observed for all the accelerators. It is concluded that the head-scatter (or collimator-scatter) factor has two ma...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.597256
更新日期：1994-01-01 00:00:00
abstract：PURPOSE:The cone beam computed tomography (CBCT) guided small animal radiation research platform (SARRP) has been developed for focal tumor irradiation, allowing laboratory researchers to test basic biological hypotheses that can modify radiotherapy outcomes in ways that were not feasible previously. CBCT provides exce...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4914860
更新日期：2015-04-01 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：:Statistical image reconstruction (SIR) methods have shown potential to substantially improve the image quality of low-dose x-ray computed tomography (CT) as compared to the conventional filtered back-projection (FBP) method. According to the maximum a posteriori (MAP) estimation, the SIR methods are typically formulat...
journal_title：Medical physics
pub_type： 杂志文章,评审
doi：10.1002/mp.13123
更新日期：2018-10-01 00:00:00
abstract：:Automatic exposure control (AEC) systems have been developed by computed tomography (CT) manufacturers to improve the consistency of image quality among patients and to control the absorbed dose. Since a multichannel helical CT scan may easily increase individual radiation doses, this technical improvement is of speci...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.2746492
更新日期：2007-07-01 00:00:00
abstract：:Significant advances have been made in recent years to improve photon dose calculation. However, accurate prediction of dose perturbation effects near the interfaces of different media, where charged particle equilibrium is not established, remain unsolved. Furthermore, changes in atomic number, which affect the multi...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.597611
更新日期：1995-07-01 00:00:00
abstract：:A new high dose rate 20 mm 32P intravascular brachytherapy (IVB) beta source used with automated stepping has recently been introduced. The AAPM Task Group 60 recommends that beta IVB sources should have well characterized dosimetric parameters in water. In this study, Monte Carlo simulations (MCNPX v 2.4) were used t...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.1646651
更新日期：2004-03-01 00:00:00
abstract：PURPOSE:To investigate the inconsistency of recent literature on the effect of magnetic field on the response of radiochromic films, we studied the influence of 0.35 T magnetic field on dosimetric response of EBT3 and EBT-XD GafchromicTM films. METHODS:Two different models of radiochromic films, EBT3 and EBT-XD, were ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.14313
更新日期：2020-09-01 00:00:00
abstract：PURPOSE:We propose a new method for efficient particle transportation in voxelized geometry for Monte Carlo simulations. We describe its use for calculating dose distribution in CT images for radiation therapy. MATERIAL AND METHODS:The proposed approach, based on an implicit volume representation named segmented volum...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.2884854
更新日期：2008-04-01 00:00:00
abstract：PURPOSE:Since the introduction of clinical x-ray phase-contrast mammography (PCM), a technique that exploits refractive-index variations to create edge enhancement at tissue boundaries, a number of optimization studies employing physical image-quality metrics have been performed. Ideally, task-based assessment of PCM w...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3676183
更新日期：2012-02-01 00:00:00
abstract：PURPOSE:The primary objective of this work is to measure the secondary neutron field produced by an uncollimated proton pencil beam impinging on different tissue-equivalent phantom materials using organic scintillation detectors. Additionally, the Monte Carlo code mcnpx-PoliMi was used to simulate the detector response...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4963813
更新日期：2016-11-01 00:00:00
abstract：:IMRT treatment plans for step-and-shoot delivery have traditionally been produced through the optimization of intensity distributions (or maps) for each beam angle. The optimization step is followed by the application of a leaf-sequencing algorithm that translates each intensity map into a set of deliverable aperture ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.1477415
更新日期：2002-06-01 00:00:00
abstract：:We have made a comparative investigation of the estimated spectra obtained by the Laplace transform analysis of the transmitted exposure data measured in an absorption study of a 4-MV x-ray beam. Four transform pair models currently used with this method have been evaluated. It has been determined that the Archer-Wagn...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.595878
更新日期：1986-05-01 00:00:00
abstract：PURPOSE:The most common metric for comparing measured to calculated dose, such as for pretreatment quality assurance of intensity-modulated photon fields, is a pass rate (%) generated using percent difference (%Diff), distance-to-agreement (DTA), or some combination of the two (e.g., gamma evaluation). For many dosimet...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3651695
更新日期：2011-11-01 00:00:00
abstract：:An anthropomorphic 1H MRS head phantom has been developed which mimics the in vivo structure, metabolite concentrations, and relaxation times (for both water and metabolites) of human brain tissue. Different brain regions and two tumor types, fluid-containing ventricles, and air-filled sinus, and subcutaneous fat are ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.598306
更新日期：1998-07-01 00:00:00
abstract：PURPOSE:There is an increasing interest in calculating linear energy transfer (LET) distributions for proton therapy treatments in order to assess the influence of this quantity in biological terms. Microdosimetric Monte Carlo (MC) simulations are useful tools to calculate dose-averaged LET, as this has been broadly pr...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.13643
更新日期：2019-09-01 00:00:00
abstract：:Conventional chest radiography is limited by the presence of scattered radiation and the small useful exposure range of radiographic film. A computer-assisted scanning system to minimize these two effects is outlined. The system uses a small beam of radiation swept over the patient's chest in a raster pattern to expos...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.595327
更新日期：1983-09-01 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：:High false-positive (FP) rate remains to be one of the major problems to be solved in CAD study because too many false-positively cued signals will potentially degrade the performance of detecting true-positive regions and increase the call-back rate in CAD environment. In this paper, we proposed a novel classificatio...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.1344203
更新日期：2001-02-01 00:00:00
abstract：:Like Medical Physics, Imaging Informatics encompasses concepts touching every aspect of the imaging chain from image creation, acquisition, management and archival, to image processing, analysis, display and interpretation. The two disciplines are in fact quite complementary, with similar goals to improve the quality ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4735777
更新日期：2012-06-01 00:00:00
abstract：:Noise, partial volume (PV) effect, and image-intensity inhomogeneity render a challenging task for segmentation of brain magnetic resonance (MR) images. Most of the current MR image segmentation methods focus on only one or two of the above-mentioned effects. The objective of this paper is to propose a unified framewo...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.1944912
更新日期：2005-07-01 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：:We report our experimental results of measurements of x-ray attenuation coefficients of aqueous solutions of a light absorbing dye, indocyanine green, and an immunoadjuvant, glycated chitosan. In the treatment of metastatic tumors in rats using a novel laser immunotherapy these solutions were administered in situ. The...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.598633
更新日期：1999-07-01 00:00:00
abstract：PURPOSE:Diffusion magnetic resonance imaging (MRI) in combination with functional MRI promises a whole new vista for scientists to investigate noninvasively the structural and functional connectivity of the human brain-the human connectome, which had heretofore been out of reach. As with other imaging modalities, diffu...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3700166
更新日期：2012-05-01 00:00:00
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：:Inverse treatment planning of intensity-modulated radiation therapy (IMRT) is complicated by several sources of error, which can cause deviations of optimized plans from the true optimal solution. These errors include the systematic and convergence error, the local minima error, and the optimizer convergence error. We...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.2896070
更新日期：2008-05-01 00:00:00
abstract：:Inherent in the line-spread function approach in modulation transfer function (MTF) determinations is the use of a microdensitometer to scan the density pattern resulting from the line exposure. In such a procedure, loss of fidelity in the distribution being scanned is expected. This loss is due in part to the use of ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.594187
更新日期：1975-09-01 00:00:00
abstract：:In this paper, we describe an algorithm to segment a needle from a three-dimensional (3D) ultrasound image by using two orthogonal two-dimensional (2D) image projections. Not only is the needle more conspicuous in a projected (volume-rendered) image, but its direction in 3D lies in the plane defined by the projection ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.1538231
更新日期：2003-02-01 00:00:00
