The NMR blood flowmeter--applications.

abstract：PURPOSE:Current on-board imaging systems commonly used by modern linear accelerators (LINACs) have a limited field of view (FOV) for a cone-beam CT (CBCT) scan, which is typically less than 50 cm. Consequently, truncation artifacts often occur for large patients. The goal of this work is to investigate a novel method t...

journal_title：Medical physics

authors： Li T,Li X,Yang Y,Heron DE,Huq MS

更新日期：2010-12-01 00:00:00

abstract：:We discuss a formalism for clinical proton beam dosimetry based on the use of ionization chamber absorbed dose-to-water calibration and beam quality correction factors. A quantity kQ, the beam quality correction factor, is defined which corrects the absorbed dose-to-water calibration factor ND,w in a reference beam of...

journal_title：Medical physics

authors： Vatnitsky SM,Siebers JV,Miller DW

更新日期：1996-01-01 00:00:00

abstract：:A measurement technique previously proposed for determining dose from primary radiation has been tested using 60Co gamma rays. It is shown that the dose from primary radiation is reliably determined for field sizes of 10 X 10 and 20 X 20 cm2 at depths of 0.5, 5, and 10 cm in water. With further development this techni...

journal_title：Medical physics

authors： Nizin PS,Kase KR

更新日期：1990-01-01 00:00:00

abstract：:Using high-energy photon and electron beams, the response of two solid water parallel-plate chambers is evaluated against a PTW (Physicallsch-Technische Werkstatten) Farmer-type chamber. These two chambers are (1) a Memorial "Holt" chamber which was further modified by this author to take advantage of electrically con...

journal_title：Medical physics

authors： Kubo H

更新日期：1993-03-01 00:00:00

abstract：:It is well established that the diffusion approximation (DA) is valid for light propagation in highly scattering media, but it breaks down in nonscattering void regions. The methods that handle the void with refractive index matched boundary were previously developed. For the void with refractive index mismatched boun...

journal_title：Medical physics

authors： Lee JH,Kim S,Kim YT

更新日期：2004-08-01 00:00:00

abstract：PURPOSE:Partial scan reconstruction (PSR) artifacts are present in myocardial perfusion imaging using dynamic multidetector computed tomography (MDCT). PSR artifacts appear as temporal CT number variations due to inconsistencies in the angular data range used to reconstruct images and compromise the quantitative value ...

journal_title：Medical physics

authors： Ramirez-Giraldo JC,Yu L,Kantor B,Ritman EL,McCollough CH

更新日期：2012-01-01 00:00:00

abstract：PURPOSE:The authors' objective was to compare internal dose estimates obtained using the Organ Level Dose Assessment with Exponential Modeling (OLINDA/EXM) software, the voxel S value technique, and Monte Carlo simulation. Monte Carlo dose estimates were used as the reference standard to assess the impact of patient-sp...

journal_title：Medical physics

authors： Grimes J,Celler A

更新日期：2014-09-01 00:00:00

abstract：PURPOSE:Radiopharmaceutical applications in nuclear medicine require a detailed dosimetry estimate of the radiation energy delivered to the human tissues. Over the past years, several publications addressed the problem of internal dose estimate in volumes of several sizes considering photon and electron sources. Most o...

journal_title：Medical physics

authors： Yoriyaz H,Moralles M,Siqueira Pde T,Guimarães Cda C,Cintra FB,dos Santos A

更新日期：2009-11-01 00:00:00

abstract：:Based on direction from AAM Board of Directors, JMPLSC has redefined its scope and name. On November 4, 2011 the subcommittee renamed itself the Medical Physics Licensure and Regulatory Recognition Subcommittee. Its newly defined charge is to promote the protection of the public through the recognition of the professi...

journal_title：Medical physics

authors： Pizzutiello R

更新日期：2012-06-01 00:00:00

abstract：PURPOSE:The aim of this paper is to investigate the accuracy of a laser∕camera surface imaging system (Sentinel) when used on patients treated in the thorax or pelvic regions and to evaluate system employment conditions and patient setup procedures that provide more accurate results. METHODS:The system was tested on t...

journal_title：Medical physics

authors： Pallotta S,Simontacchi G,Marrazzo L,Ceroti M,Paiar F,Biti G,Bucciolini M

更新日期：2013-01-01 00:00:00

abstract：PURPOSE:In this work the performance of a compact multiresolution and multicontrast x-ray phase system based on edge illumination is investigated. It has been designed for small animal imaging and with a limited footprint for ease of deployment in laboratories. METHODS:The presented edge illumination system is based o...

journal_title：Medical physics

authors： Massimi L,Meganck JA,Towns R,Olivo A,Endrizzi M

更新日期：2020-10-27 00:00:00

abstract：:A new type of radiographic film, EDR (extended dose range) film, has been recently become available for film dosimetry. It is particularly attractive for composite isodose verification of intensity modulated radiation therapy because of its low sensitivity relative to the more common Kodak XV film. For XV film, the re...

journal_title：Medical physics

authors： Zhu XR,Yoo S,Jursinic PA,Grimm DF,Lopez F,Rownd JJ,Gillin MT

更新日期：2003-05-01 00:00:00

abstract：:Cardiac arrhythmias are a major health burden, associated with reduced quality of life and substantial morbidity and mortality. Current therapy includes moderately effective medication and catheter-based ablation of arrhythmogenic substrates in the heart. Catheter interventions frequently have to be repeated due to re...

journal_title：Medical physics

authors： Graeff C,Bert C

更新日期：2018-11-01 00:00:00

abstract：:An energy discriminating detector for dual-energy radiography can be configured as a two-layer sandwich, where the mean energy of photons detected by the two layers differs. To characterize the quantum noise of such a detector, the noise covariance between the two layers must be known in addition to the noise variance...

journal_title：Medical physics

authors： Sones RA,Barnes GT

更新日期：1989-11-01 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

authors： Huang CY,Oborn BM,Guatelli S,Allen BJ

更新日期：2012-03-01 00:00:00

abstract：PURPOSE:X-ray fluorescence (XRF) is a promising technique with sufficient specificity and sensitivity for identifying and quantifying features in small samples containing high atomic number (Z) materials such as iodine, gadolinium, and gold. In this study, the feasibility of applying XRF to early breast cancer diagnosi...

journal_title：Medical physics

authors： Ren L,Wu D,Li Y,Wang G,Wu X,Liu H

更新日期：2014-03-01 00:00:00

abstract：:Digital tomosynthesis (DTS) is a fast, low-dose three-dimensional (3D) imaging approach which yields slice images with excellent in-plane resolution, though low plane-to-plane resolution. A stack of DTS slices can be reconstructed from a single limited-angle scan, with typical scan angles ranging from 10 degrees to 40...

journal_title：Medical physics

authors： Godfrey DJ,Ren L,Yan H,Wu Q,Yoo S,Oldham M,Yin FF

更新日期：2007-08-01 00:00:00

abstract：:A beam stop technique was used to measure the densitometric scatter fractions under three regions of a humanoid chest phantom utilizing LaOBr and Gd2O2S screens. For these receptors, the scatter fractions under the lung and retrocardiac areas were 13%-36% lower than published values for CaWO4. In the mediastinal area,...

journal_title：Medical physics

authors： Petrone TJ,Steidley KD

更新日期：1993-03-01 00:00:00

abstract：PURPOSE:Plastic scintillation detectors are used for dosimetry in small radiation fields with high dose gradients, e.g., provided by β-emitting sources like 106 Ru/106 Rh eye plaques. A drawback is a background signal caused by Cerenkov radiation generated by electrons passing the optical fibers (light guides) of this ...

journal_title：Medical physics

authors： Eichmann M,Thomann B

更新日期：2017-09-01 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

authors： Ma G,Gao Y,Wu G,Wu L,Shen D

更新日期：2016-02-01 00:00:00

abstract：:Generating an optimized radiation treatment plan requires understanding the factors affecting tumour control. Mathematical models of tumour dynamics may help in future studies of factors predicting tumor sensitivity to radiotherapy. In this study, a time-dependent differential model, incorporating biological cancer ma...

journal_title：Medical physics

authors： Campbell A,Davidson M,Lock M,Wong E

更新日期：2008-07-01 00:00:00

abstract：PURPOSE:The need for four-dimensional (4D) treatment planning becomes indispensable when it comes to radiation therapy for moving tumors in the thoracic and abdominal regions. The primary purpose of this study is to combine the actual breathing trace during each individual treatment fraction with the Linac's log file i...

journal_title：Medical physics

authors： Freislederer P,von Münchow A,Kamp F,Heinz C,Gerum S,Corradini S,Söhn M,Reiner M,Roeder F,Floca R,Alber M,Belka C,Parodi K

更新日期：2019-07-01 00:00:00

abstract：PURPOSE:The aiming is getting accurate liver contour structures automatically for following adaptive radiation therapy in daily CBCT images which is very low-contrast comparing the planning CT. METHODS:Probabilistic atlas is constructed by 50 intravenous contrast planning CT images by iterative affine registration pro...

journal_title：Medical physics

authors： Li D,Li H,Yin Y,Chen J

更新日期：2012-06-01 00:00:00

abstract：:An important aspect of the intensity modulated radiotherapy (IMRT) process is that of optimizing the beam intensity profiles. Most such methods use a comparison between the defined dose distribution (including prescription dose and dose limits for critical structures) and the current distribution. The comparison may i...

journal_title：Medical physics

authors： Jones L,Hoban P

更新日期：2002-01-01 00:00:00

abstract：PURPOSE:Since the first publications on intensity modulated radiation therapy (IMRT) in the early 1980s almost all efforts have been focused on fairly time consuming dynamic or segmental multileaf collimation. With narrow fast scanned photon beams, the flexibility and accuracy in beam shaping increases, not least in co...

journal_title：Medical physics

authors： Andreassen B,Strååt SJ,Holmberg R,Näfstadius P,Brahme A

更新日期：2011-08-01 00:00:00

abstract：:In this x-ray/MR hybrid system an x-ray flat panel detector is placed under the patient cradle, close to the MR volume of interest (VOI), where the magnetic field strength is approximately 0.5 T. Immersed in this strong field, several electronic components inside the detector become magnetized and create an additional...

journal_title：Medical physics

authors： Wen Z,Fahrig R,Williams ST,Pelc NJ

更新日期：2008-09-01 00:00:00

abstract：PURPOSE:A number of techniques are available to determine the dosimetric impact of intrafraction motion during intensity modulated radiation therapy (IMRT). Motion-induced dose perturbations can be determined both computationally and experimentally using a number of different dosimetric metrics. However, these measures...

journal_title：Medical physics

authors： Waghorn BJ,Meeks SL,Langen KM

更新日期：2011-08-01 00:00:00

abstract：PURPOSE:Modern clinical accelerators are capable of producing ion beams from protons up to neon. This work compares the depth dose distribution and corresponding dose averaged linear energy transfer (LET) distribution, which is related to the biological effectiveness, for different ion beams (¹H, ⁴He, ⁶Li, ⁸Be, ¹⁰B, ¹²...

journal_title：Medical physics

authors： Kantemiris I,Karaiskos P,Papagiannis P,Angelopoulos A

更新日期：2011-12-01 00:00:00

abstract：:A method for finding optimal primary fluence profiles for multiple field external beam radiation therapy techniques has been developed using a radiobiologically based objective function that quantifies the probability of achieving complication-free tumor control, P+. The objective function P+ has the valuable property...

journal_title：Medical physics

authors： Södertröm S,Brahme A

更新日期：1993-07-01 00:00:00

abstract：:Due to practical limitations in data acquisition, 3-D computed tomography systems must attempt to provide rapid reconstructions of acceptable quality from a limited number of views. The use of convolution backprojection (CBP) for image reconstruction from an inadequate number of projections, results in view aliasing a...

journal_title：Medical physics

authors： Galigekere RR,Wiesent K,Holdsworth DW

更新日期：1999-06-01 00:00:00