Abstract：
:An addendum to the AAPM's TG-51 protocol for the determination of absorbed dose to water in megavoltage photon beams is presented. This addendum continues the procedure laid out in TG-51 but new kQ data for photon beams, based on Monte Carlo simulations, are presented and recommendations are given to improve the accuracy and consistency of the protocol's implementation. The components of the uncertainty budget in determining absorbed dose to water at the reference point are introduced and the magnitude of each component discussed. Finally, the consistency of experimental determination of ND,w coefficients is discussed. It is expected that the implementation of this addendum will be straightforward, assuming that the user is already familiar with TG-51. The changes introduced by this report are generally minor, although new recommendations could result in procedural changes for individual users. It is expected that the effort on the medical physicist's part to implement this addendum will not be significant and could be done as part of the annual linac calibration.
journal_name
Med Physjournal_title
Medical physicsauthors
McEwen M,DeWerd L,Ibbott G,Followill D,Rogers DW,Seltzer S,Seuntjens Jdoi
10.1118/1.4866223subject
Has Abstractpub_date
2014-04-01 00:00:00pages
041501issue
4eissn
0094-2405issn
2473-4209journal_volume
41pub_type
杂志文章相关文献
MEDICAL PHYSICS文献大全abstract：:The precision of noninvasive optical measurement of the concentration changes in oxy-, deoxy-, and total-hemoglobin depends on wavelength. For estimating the precision, we calculated the noise level of the concentration changes as the uncertainty in measurements using several wavelength pairs of light. Seven laser dio...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.1373401
更新日期：2001-06-01 00:00:00
abstract：:We have developed two prototypes of portable gamma cameras for medical applications based on a previous prototype designed and tested by our group. These cameras use a CsI(Na) continuous scintillation crystal coupled to the new flat-panel-type multianode position-sensitive photomultiplier tube, H8500 from Hamamatsu Ph...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.2358199
更新日期：2006-11-01 00:00:00
abstract：PURPOSE:Theoretical reasoning suggests that direct conversion digital x-ray detectors based upon photoconductive amorphous-selenium (a-Se) could attain very high values of the MTF (modulation transfer function) at spatial frequencies well beyond 20 cycles mm(-1). One of the fundamental factors affecting resolution loss...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3673957
更新日期：2012-02-01 00:00:00
abstract：PURPOSE:To determine if NSCLC GTV CT textures can be predictive for tumor shrinkage after proton therapy with concurrent chemotherapy. METHODS:Simulation and weekly 4DCTs were obtained from 25 patients with locally advanced NSCLC treated by proton therapy at a 74 Gy dose level with concurrent chemotherapy. In-house de...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4735027
更新日期：2012-06-01 00:00:00
abstract：PURPOSE:To validate GPUMCD, a new package for fast Monte Carlo dose calculations based on the GPU (graphics processing unit), as a tool for low-energy single seed brachytherapy dosimetry for specific seed models. As the currently accepted method of dose calculation in low-energy brachytherapy computations relies on sev...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3598441
更新日期：2011-07-01 00:00:00
abstract：:With the increased sophistication of lasers used for patient positioning in radiotherapy comes increased possibilities for mistakes in installing the lasers, which can result in serious patient positioning errors. Two principles must be followed when mounting cross-projecting lasers: (1) the horizontal line must be on...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.594960
更新日期：1981-05-01 00:00:00
abstract：:Dose calculations for treatment planning of photon beam radiotherapy require a model of the beam to drive the dose calculation models. The beam shaping process involves scattering and filtering that yield radiation components which vary with collimator settings. The necessity to model these components has motivated th...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.1898485
更新日期：2005-06-01 00:00:00
abstract：:Image correlation is often required to utilize the complementary information in CT, MRI, and SPECT. A practical method for automatic image correlation in three-dimensions (3D) based on chamfer matching is described. The method starts with automatic extraction of contour points in one modality and automatic segmentatio...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.597344
更新日期：1994-07-01 00:00:00
abstract：:A single-field rotational total skin electron irradiation technique has recently been developed at the McGill University for treatment of skin malignancies. The dose received by a given surface point during rotation in a uniform large electron field depends on the radius of rotation of the surface point, on the local ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.595524
更新日期：1984-07-01 00:00:00
abstract：PURPOSE:Liver segmentation is an important prerequisite for the assessment of liver cancer treatment options like tumor resection, image-guided radiation therapy (IGRT), radiofrequency ablation, etc. The purpose of this work was to evaluate a new approach for liver segmentation. METHODS:A graph cuts segmentation metho...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3682171
更新日期：2012-03-01 00:00:00
abstract：PURPOSE:To design volume-specific breast phantoms from breast CT (bCT) data sets and estimate the associated normalized mean glandular dose coefficients for breast CT using Monte Carlo methods. METHODS:A large cohort of bCT data sets (N = 215) was used to evaluate breast volume into quintiles (plus the top 5%). The av...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.12477
更新日期：2017-10-01 00:00:00
abstract：PURPOSE:This article presents a new reconstruction method for 3D imaging using a multiple 360 degrees circular orbit cone beam CT system, specifically a way to combine 3D volumes reconstructed with each orbit. The main goal is to improve the noise performance in the combined image while avoiding cone beam artifacts. M...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3484058
更新日期：2010-10-01 00:00:00
abstract：:A fully automatic radiophotoluminescent glass rod dosimeter (GRD) system has recently become commercially available. This article discusses the dosimetric properties of the GRD including uniformity and reproducibility of signal, dose linearity, and energy and directional dependence in high-energy photon beams. In addi...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.1758351
更新日期：2004-07-01 00:00:00
abstract：PURPOSE:A three-dimensional finite element analysis based canine heart model is introduced that would enable the assessment of cardiac function. METHODS:The three-dimensional canine heart model is based on the cardiac deformation and motion model obtained from the Cardiac Mechanics Research Group at UCSD. The canine h...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3496326
更新日期：2010-11-01 00:00:00
abstract：:Many problems in physics involve imaging objects with high spatial frequency content in a limited amount of time. The limitation of available experimental data leads to the infamous problem of diffraction limited data which manifests itself by causing ringing in the image. This ringing is due to the interference pheno...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.596427
更新日期：1989-05-01 00:00:00
abstract：PURPOSE:To estimate organ and effective radiation doses due to backscatter security scanners using Monte Carlo simulations and a voxelized phantom set. METHODS:Voxelized phantoms of male and female adults and children were used with the GEANT4 toolkit to simulate a backscatter security scan. The backscatter system was...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4718680
更新日期：2012-06-01 00:00:00
abstract：:The performance of an indirect-detection, active matrix flat-panel imager (FPI) at diagnostic energies is reported in terms of measured and theoretical signal size, noise power spectrum (NPS), and detective quantum efficiency (DQE). Based upon a 1536 x 1920 pixel, 127 microns pitch array of a-Si:H thin-film transistor...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.598243
更新日期：1998-05-01 00:00:00
abstract：:The use of characteristic-line radiation from rare-earth targets bombarded by high-energy (up to 1 MeV) electron beams has been evaluated as an x-ray source for dual energy K-edge subtraction imaging of the human coronary arteries. Two characteristic-line x-ray sources, one using the split K alpha 1 and K alpha 2 line...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.596648
更新日期：1991-09-01 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
pub_type： 杂志文章
doi：10.1118/1.3284974
更新日期：2010-02-01 00:00:00
abstract：:Atomic Energy of Canada Limited 60Co teletherapy units have adjustable collimator hinges to adapt to source diameters from 0.75 to 2.50 cm. Adjustment of the collimator hinge to the manfacturer's settings can cause a loss of radiation field flatness as high as 20% for large fields. The recommended settings appear to c...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.594170
更新日期：1975-03-01 00:00:00
abstract：PURPOSE:Manual delineation of head and neck (H&N) organ-at-risk (OAR) structures for radiation therapy planning is time consuming and highly variable. Therefore, we developed a dynamic multiatlas selection-based approach for fast and reproducible segmentation. METHODS:Our approach dynamically selects and weights the a...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.13854
更新日期：2019-12-01 00:00:00
abstract：:The modulation transfer function (MTF) and the noise power spectrum (NPS) are widely recognized as the most relevant metrics of resolution and noise performance in radiographic imaging. These quantities have commonly been measured using various techniques, the specifics of which can have a bearing on the accuracy of t...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.2188816
更新日期：2006-05-01 00:00:00
abstract：PURPOSE:A radiophotoluminescent glass rod dosimeter (RGD) has recently become commercially available. It is being increasingly used for dosimetry in radiotherapy to measure the absorbed dose including scattered low-energy photons on the body surface of a patient and for postal dosimetry audit. In this article, the dosi...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4747261
更新日期：2012-10-01 00:00:00
abstract：PURPOSE:A nanodosimeter is a type of detector which measures single ionizations in a small gaseous volume in order to obtain ionization cluster size probability distributions for characterization of radiation types. Working nanodosimeter detectors are usually bulky machines which require a lot of space. In this work, t...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.14738
更新日期：2021-01-28 00:00:00
abstract：PURPOSE:The aim of this study was to investigate the effect of scatter and its correction on kinetic parameters in dynamic brain positron emission tomography (PET) tumor imaging. The 2-tissue compartment model was used, and two different reconstruction methods and two scatter correction (SC) schemes were investigated. ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4897610
更新日期：2014-11-01 00:00:00
abstract：PURPOSE:It is important for many quantitative brain studies to label meaningful anatomical regions in MR brain images. However, due to high complexity of brain structures and ambiguous boundaries between different anatomical regions, the anatomical labeling of MR brain images is still quite a challenging task. In many ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4940399
更新日期：2016-02-01 00:00:00
abstract：PURPOSE:Brachytherapy with 106 Ru/106 Rh plaques offers good outcomes for small-to-medium choroidal melanomas and retinoblastomas. The dose measurement of the plaques is challenging, due to the small range of the emitted beta particles and steep dose gradients involved. The scarce publications on film dosimetry of 106 ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.12777
更新日期：2018-04-01 00:00:00
abstract：PURPOSE:There are several options to consider in the design of a vault that will house a cyclotron for radioisotopes production with regards to the door entrance. Alternatives are a direct-shielded door, a simple maze, or a double-legged maze. In this work, the impact of the neutron and photon doses at the vault entran...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3515458
更新日期：2010-12-01 00:00:00
abstract：:A novel iterative penalized likelihood algorithm with evolutionary components for the optimization of beamlet fluences for intensity modulated radiation therapy (IMRT) is presented. This algorithm is designed to be flexible in terms of the objective function and automatically escalates dose, as long as the objective f...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.1773631
更新日期：2004-08-01 00:00:00
abstract：PURPOSE:The Monte Carlo simulation of electron transport in Linac targets using the condensed history technique is known to be problematic owing to a potential dependence of absorbed dose distributions on the electron step length. In the PENELOPE code, the step length is partially determined by the transport parameters...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4916686
更新日期：2015-06-01 00:00:00
