Verification of treatment parameter transfer by means of electronic portal dosimetry.

abstract：PURPOSE:MR thermometry based on the proton resonance frequency shift (PRFS) is the most commonly used method for the monitoring of thermal therapies. As the chemical shift of water protons is temperature dependent, the local temperature variation (relative to an initial baseline) may be calculated from time-dependent p...

journal_title：Medical physics

authors： Viallon M,Terraz S,Roland J,Dumont E,Becker CD,Salomir R

更新日期：2010-04-01 00:00:00

abstract：PURPOSE:The variable resolution x-ray (VRX) CT scanner provides substantial improvement in the spatial resolution by matching the scanner's field of view (FOV) to the size of the object being imaged. Intercell x-ray cross-talk is one of the most important factors limiting the spatial resolution of the VRX detector. In ...

journal_title：Medical physics

authors： Arabi H,Asl AR,Ay MR,Zaidi H

更新日期：2011-03-01 00:00:00

abstract：:Testing computer-controlled linear accelerators for patient safety and proper patient dose delivery requires that certain beam characteristics be monitored over an extended period of time. Computer-controlled conformal radiation therapy using asymmetric collimator jaw settings necessitates stable symmetric treatment b...

journal_title：Medical physics

authors： Loyd MD,Lane RG,Laxton J,Chow CH,Rosen II

更新日期：1989-07-01 00:00:00

abstract：:Neutron energy spectra and spectra of dose deposition in tissue-equivalent material have been measured for neutron sources produced by 16-, 22-, 35-, and 45.5-MeV deuterons and 22.5-, 35-, 45-, and 65.5-MeV protons incident upon a thick beryllium target. Neutron spectra were measured using time-of-flight techniques an...

journal_title：Medical physics

authors： Heintz PH,Johnsen SW,Peek NF

更新日期：1977-05-01 00:00:00

abstract：PURPOSE:Incorporating training into image segmentation is a good approach to achieve additional robustness. This work aims to develop an effective strategy to utilize shape prior knowledge, so that the segmentation label evolution can be driven toward the desired global optimum. METHODS:In the variational image segmen...

journal_title：Medical physics

authors： Zhao T,Ruan D

更新日期：2016-05-01 00:00:00

abstract：PURPOSE:The primary feasibility steps of demonstrating the ability of microwave-induced thermoacoustic (TA) in phantoms have been previously reported. However, none were shown to target a diseased site in living subjects in thermoacoustic tomography (TAT) field so far. To determine the expressions of oncogenic surface ...

journal_title：Medical physics

authors： Nie L,Ou Z,Yang S,Xing D

更新日期：2010-08-01 00:00:00

abstract：:Scanning film densitometry routinely used for obtaining dosimetric information about therapy treatment beams is subject to several sources of inaccuracies. The most significant of these are described and appropriate methods of testing are presented. This establishes the need for adequate acceptance testing followed by...

journal_title：Medical physics

authors： Holmes TW,McCullough EC

更新日期：1983-09-01 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：:In this work, gray-scale invariant ranklet texture features are proposed for false positive reduction (FPR) in computer-aided detection (CAD) of breast masses. Two main considerations are at the basis of this proposal. First, false positive (FP) marks surviving our previous CAD system seem to be characterized by speci...

journal_title：Medical physics

authors： Masotti M,Lanconelli N,Campanini R

更新日期：2009-02-01 00:00:00

abstract：:A simple method to measure the line spread function of computed tomographic scanners has been developed. The line spread function of the EMI-Scanner was measured and the MTF of the scanner was calculated. The reproducibility of the method indicated this technique could be utilized to compare the spatial resolution of ...

journal_title：Medical physics

authors： Judy PF

更新日期：1976-07-01 00:00:00

abstract：PURPOSE:This study (1) examines a variety of real-world cases where systematic errors were not detected by widely accepted methods for IMRT/VMAT dosimetric accuracy evaluation, and (2) drills-down to identify failure modes and their corresponding means for detection, diagnosis, and mitigation. The primary goal of detai...

journal_title：Medical physics

authors： Nelms BE,Chan MF,Jarry G,Lemire M,Lowden J,Hampton C,Feygelman V

更新日期：2013-11-01 00:00:00

abstract：PURPOSE:State of the art to access radiofrequency (RF) heating near implants is computer modeling of the devices and solving Maxwell's equations for the specific setup. For a set of input parameters, a fixed result is obtained. This work presents a theoretical approach in the alternating current (ac) limit, which can p...

journal_title：Medical physics

authors： Ballweg V,Eibofner F,Graf H

更新日期：2011-10-01 00:00:00

abstract：:Small photon fields are increasingly used in modern radiotherapy and especially in IMRT and SRS/SRT treatments. The uncertainties related to small field profile measurements can introduce significant systematic errors to the overall treatment process. These measurements are challenging mainly due to the absence of cha...

journal_title：Medical physics

authors： Pappas E,Maris TG,Zacharopoulou F,Papadakis A,Manolopoulos S,Green S,Wojnecki C

更新日期：2008-10-01 00:00:00

abstract：:This paper examines statistical errors in the measurement of arterial stenoses by digital videodensitometry. Images of vessel phantoms were acquired using digital subtraction angiographic techniques with low concentrations of an iodine contrast medium and low levels of x-ray exposure. Effects of the spatial and tempor...

journal_title：Medical physics

authors： Wright GA,Taylor KW,Rowlands JA

更新日期：1985-11-01 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

authors： Vasi F,Schneider U

更新日期：2021-01-28 00:00:00

abstract：:Plaque rupture with superimposed thrombosis is the main cause of the acute coronary syndromes of unstable angina, myocardial infarction, and sudden death. Endothelial disruption leading to plaque rupture may relate to mechanical fatigue associated with cyclic flexion of plaques. A novel method is proposed to assess st...

journal_title：Medical physics

authors： Wu HC,Chen SY,Shroff SG,Carroll JD

更新日期：2003-11-01 00:00:00

abstract：PURPOSE:Two-dimensional ultrasound (2D US) imaging is commonly used for diagnostic and intraoperative guidance of interventional liver procedures; however, 2D US lacks volumetric information that may benefit interventional procedures. Over the past decade, three-dimensional ultrasound (3D US) has been developed to prov...

journal_title：Medical physics

authors： Neshat H,Cool DW,Barker K,Gardi L,Kakani N,Fenster A

更新日期：2013-11-01 00:00:00

abstract：PURPOSE:To balance dose reduction and image registration accuracy in breast setup imaging. In particular, the authors demonstrate the relationship between scan angle and dose delivery for cone beam tomosynthesis (CBTS) when employed for setup verification of breast cancer patients with surgical clips. METHODS:The dose...

journal_title：Medical physics

authors： Winey BA,Zygmanski P,Cormack RA,Lyatskaya Y

更新日期：2010-08-01 00:00:00

abstract：PURPOSE:To identify which physical properties of nanoparticles are correlated with the survival fraction of cells exposed in vitro to low-energy protons in combination with nanoparticles. METHODS:The Geant4 simulation toolkit (version 10.3) was used to model nanoparticles of different sizes (5-50 nm) and materials (Ti...

journal_title：Medical physics

authors： Heuskin AC,Gallez B,Feron O,Martinive P,Michiels C,Lucas S

更新日期：2017-08-01 00:00:00

abstract：PURPOSE:Intraventricular hemorrhage (IVH) is a major cause of brain injury in preterm neonates. Three dimensional ultrasound (US) imaging systems have been developed to visualize 3D anatomical structure of preterm neonatal intracranial ventricular system with IVH and ventricular dilation. To allow quantitative analysis...

journal_title：Medical physics

authors： Chen Y,Qiu W,Kishimoto J,Gao Y,Chan RH,de Ribaupierre S,Fenster A,Chiu B

更新日期：2015-11-01 00:00:00

abstract：PURPOSE:Prostate cancer ranks as one of the most common malignancies and currently represents the second leading cancer-specific cause of death in men. The current use of single modality transrectal ultrasound (TRUS) for biopsy guidance has a limited sensitivity and specificity for accurately identifying cancerous lesi...

journal_title：Medical physics

authors： Wan Y,Borsic A,Heaney J,Seigne J,Schned A,Baker M,Wason S,Hartov A,Halter R

更新日期：2013-06-01 00:00:00

abstract：:A new scheme, called direct aperture deformation (DAD), for online correction of interfraction geometric uncertainties under volumetric imaging guidance is presented. Using deformable image registration, the three-dimensional geometric transformation matrix can be derived that associates the planning image set and the...

journal_title：Medical physics

authors： Feng Y,Castro-Pareja C,Shekhar R,Yu C

更新日期：2006-12-01 00:00:00

abstract：PURPOSE:To present EBT2 film verification of treatment planning with the eXtend System, a relocatable frame system for multiple-fraction or serial multiple-session radiosurgery. METHODS:A human head shaped phantom simulated the verification process for fractionated Gamma Knife (GK) treatment. Phantom preparation for e...

journal_title：Medical physics

authors： Gopishankar N,Bisht RK

更新日期：2012-06-01 00:00:00

abstract：BACKGROUND AND PURPOSE:Differential baseline shifts between primary tumor and involved lymph nodes in locally advanced lung cancer patients compromise the accuracy of radiotherapy. The purpose of this study was to evaluate the performance of an average anatomy model (AAM) derived from repeat imaging and deformable regi...

journal_title：Medical physics

authors： Abdoli M,Van Kranen SR,Stankovic U,Rossi MMG,Belderbos JSA,Sonke JJ

更新日期：2017-07-01 00:00:00

abstract：:Monte Carlo calculations have been performed for the purpose of characterizing the dosimetric properties of three brachytherapy sources. The three sources are manufactured by Syncor Pharmaceuticals Inc. and consist of two 125I seeds (BT-125-1 and BT-125-2) and one 103Pd seed (BT-103-3). The BT-125-1 and BT-125-2 seed ...

journal_title：Medical physics

authors： DeMarco JJ,Hugo G,Solberg TD

更新日期：2002-05-01 00:00:00

abstract：PURPOSE:For the past two decades, high-Z nanoparticles have been of high interest to improve the therapeutic outcomes of radiation therapy, especially for low-energy X-rays. Monte Carlo (MC) simulations have been used to evaluate the boost of dose deposition induced by Auger electrons near the nanoparticle surface, by ...

journal_title：Medical physics

authors： Poignant F,Monini C,Testa É,Beuve M

更新日期：2020-11-04 00:00:00

abstract：PURPOSE:Within the European project ALLEGRO (grant agreement no. 231965), the out-of-field dose delivered to a patient when treated with different radiotherapy modalities was investigated. The study compared the dose distribution during photon and particle irradiations both in a water and an anthropomorphic phantom to ...

journal_title：Medical physics

authors： Kaderka R,Durante M,Berger T,Reitz G,Tessa C

更新日期：2012-06-01 00:00:00

abstract：PURPOSE:The purpose of this study is to estimate the effect of edema, developed during implant procedure, on tumor cell surviving fraction(SF) and tumor control probability(TCP) in the patients of prostate cancer who underwent 131 Cs permanent seed implants. METHODS:The impact of edema on SF and TCP, was calculated us...

journal_title：Medical physics

authors： Kehwar TS,Huq MS,Smith RP

更新日期：2012-06-01 00:00:00

abstract：PURPOSE:Cone beam computed tomography (CBCT) image quality suffers from contamination from scattered photons in the projection images. Monte Carlo simulations are a powerful tool to investigate the properties of scattered photons.egs_cbct, a recent EGSnrc user code, provides the ability of performing fast scatter calcu...

journal_title：Medical physics

authors： Thing RS,Mainegra-Hing E

更新日期：2014-07-01 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

authors： Kawrakow I

更新日期：2006-06-01 00:00:00