Patient specific optimization of the relation between CT-hounsfield units and proton stopping power with proton radiography.

abstract：PURPOSE:The recent introduction of digital tomosynthesis imaging into routine clinical use has enabled the acquisition of volumetric patient data within a standard radiographic examination. Tomosynthesis requires the acquisition of multiple projection views, requiring additional dose compared to a standard projection e...

journal_title：Medical physics

authors： Sabol JM

更新日期：2009-12-01 00:00:00

abstract：:The bremsstrahlung spectrum from an 8-MeV linear accelerator has been measured using a NaI(T1) spectrometer system. The spectrum shows a low-energy cutoff at 0.4 MeV and the maximum photon energy to be approximately 6% greater than the nominal energy. The maximum emission of energy fluence was 1.6 and 1.8 MeV for meas...

journal_title：Medical physics

authors： Levy LB,Waggener RG,Wright AE

更新日期：1976-05-01 00:00:00

abstract：PURPOSE:To quantify detector perturbation effects in megavoltage small photon fields and support the theoretical explanation on the nature of quality correction factors in these conditions. METHODS:In this second paper, a modern approach to radiation dosimetry is defined for any detector and applied to small photon fi...

journal_title：Medical physics

authors： Bouchard H,Kamio Y,Palmans H,Seuntjens J,Duane S

更新日期：2015-10-01 00:00:00

abstract：:The authors are investigating the concept of a direct-conversion flat-panel imager with avalanche gain for low-dose x-ray imaging. It consists of an amorphous selenium (a-Se) photoconductor partitioned into a thick drift region for x-ray-to-charge conversion and a relatively thin region called high-gain avalanche rush...

journal_title：Medical physics

authors： Wronski MM,Rowlands JA

更新日期：2008-12-01 00:00:00

abstract：PURPOSE:The treatment of thoracic cancer using external beam radiation requires an optimal selection of the radiation beam directions to ensure effective coverage of the target volume and to avoid unnecessary treatment of normal healthy tissues. Intensity modulated radiation therapy (IMRT) planning is a lengthy process...

journal_title：Medical physics

authors： Amit G,Purdie TG,Levinshtein A,Hope AJ,Lindsay P,Marshall A,Jaffray DA,Pekar V

更新日期：2015-04-01 00:00:00

abstract：:This study proposes an algorithm for selecting beam weight, wedge angle, and wedge orientation for three-dimensional radiation therapy treatment planning. According to dose gradient analysis, the necessary and sufficient condition for achieving a homogeneous dose over the target volume is that the total vector sum of ...

journal_title：Medical physics

authors： Dai J,Zhu Y

更新日期：2000-08-01 00:00:00

abstract：:Stereotactic Body Radiation Therapy (SBRT) is an important form of cancer therapy with increasingly broad application across a spectrum of tumor types in primary and metastatic settings. In this presentation the radiation biology, clinical experience from various trials, and cautionary updates on normal tissue toleran...

journal_title：Medical physics

authors： Read P

更新日期：2012-06-01 00:00:00

abstract：PURPOSE:In prostate radiotherapy, dose distribution may be calculated on CT images, while the MRI can be used to enhance soft tissue visualization. Therefore, a registration between MR and CT images could improve the overall treatment planning process, by improving visualization with a demonstrated interobserver deline...

journal_title：Medical physics

authors： Hamdan I,Bert J,Rest CCL,Tasu JP,Boussion N,Valeri A,Dardenne G,Visvikis D

更新日期：2017-12-01 00:00:00

abstract：PURPOSE:Repeated brain MRI scans are performed in many clinical scenarios, such as follow up of patients with tumors and therapy response assessment. In this paper, the authors show an approach to utilize former scans of the patient for the acceleration of repeated MRI scans. METHODS:The proposed approach utilizes the...

journal_title：Medical physics

authors： Weizman L,Eldar YC,Ben Bashat D

更新日期：2015-09-01 00:00:00

abstract：:This study presents experimental results about the effective depth of penetration and about the radiofrequency (rf) power absorption in humans as a function of frequency. The frequency range investigated covers 10 up to 220 MHz. For the main part, the results were derived from bench measurements of the quality factor ...

journal_title：Medical physics

authors： Röschmann P

更新日期：1987-11-01 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

authors： Zhang H,Wang J,Zeng D,Tao X,Ma J

更新日期：2018-10-01 00:00:00

abstract：PURPOSE:In the past decade, phase-contrast imaging (PCI) has been applied to study different kinds of tissues and human body parts, with an increased improvement of the image quality with respect to simple absorption radiography. A technique closely related to PCI is phase-retrieval imaging (PRI). Indeed, PCI is an ima...

journal_title：Medical physics

authors： De Caro L,Scattarella F,Giannini C,Tangaro S,Rigon L,Longo R,Bellotti R

更新日期：2010-07-01 00:00:00

abstract：PURPOSE:Many biological objects, including neuronal dendrites, blood vasculature, airways, phylogenetic trees, produce tree structured data. Current methods of analysis either ignore the complex structure of trees or use distance-based methods which limit the scope of multivariate modeling. METHODS:We propose a branch...

journal_title：Medical physics

authors： Roy Choudhury K,Skwerer S

更新日期：2018-03-01 00:00:00

abstract：PURPOSE:Stereotactic body radiation therapy (SBRT) is a radiotherapy technique which uses high dose fractions with multiple coplanar and noncoplanar beams. Due to the large fractional doses, treatments are typically protracted and there are more fields than in conventional radiation treatment schemes. The effect of tem...

journal_title：Medical physics

authors： Schmitt JD,Warren GW,Wang IZ

更新日期：2012-06-01 00:00:00

abstract：PURPOSE:Photoacoustic imaging has proven to be able to detect vascularization-driven optical absorption contrast associated with tumors. In order to detect breast tumors located a few centimeter deep in tissue, a sensitive ultrasound detector is of crucial importance for photoacoustic mammography. Further, because the ...

journal_title：Medical physics

authors： Xia W,Piras D,van Hespen JC,van Veldhoven S,Prins C,van Leeuwen TG,Steenbergen W,Manohar S

更新日期：2013-03-01 00:00:00

abstract：:As a potentially important technology for medical x-ray computed tomography (CT), lambda tomography (LT) is to reconstruct a gradient-like image only from local projection data. Based on our recently derived exact fan-beam LT formula, [H. Y. Gu and G. Wang, Int. J. Biomed. Imaging 2006(1), 1-9 (2006)] here we propose ...

journal_title：Medical physics

authors： Yu H,Ye Y,Wang G

更新日期：2006-10-01 00:00:00

abstract：:A four-parameter Laplace transform pair model, which accurately reconstructs an experimental bremsstrahlung spectrum from attenuation data, is presented. Computed spectral values with both aluminum and copper attenuators generally agree with experimental 70-kVp data to better than 2%. Reconstructed spectra at other kV...

journal_title：Medical physics

authors： Archer BR,Wagner LK

更新日期：1982-11-01 00:00:00

abstract：PURPOSE:X-ray fluorescence computed tomography (XFCT) experiments have typically used pencil beams for data acquisition, which yielded good quality images of gold nanoparticles (AuNP) but prolonged the imaging time. Here we propose three novel collimator geometries for use with faster sheet beam XFCT data acquisition. ...

journal_title：Medical physics

authors： Dunning CAS,Bazalova-Carter M

更新日期：2018-06-01 00:00:00

abstract：:A combination of Monte Carlo, convolution, and experimental techniques have been used to investigate bremsstrahlung production at 50 MeV in full-range targets to produce narrow elementary photon beams for scanning. Calculations using the ITS 3.0 Monte Carlo system for various target designs, including particle transpo...

journal_title：Medical physics

authors： Sätherberg A,Andreo P,Karlsson M

更新日期：1996-04-01 00:00:00

abstract：PURPOSE:To evaluate if the recently described problems with the calibration of jaws at Varian linear accelerators can be detected with the DAVID system. METHODS:Recently Varian Clinac field size issues resulted in a widespread medical device correction notice, stating that incorrect jaw positioning due to excessive co...

journal_title：Medical physics

authors： Poppe B,Looe H,Harder D

更新日期：2012-06-01 00:00:00

abstract：:In this work, the authors have evaluated ten different ionization chambers for the relative dosimetry of kilovoltage x-ray beams in the energy range of 50-280 kVp. Percentage depth doses in water and relative detector response (in Solid Water and in air) were measured for each of the x-ray beams studied using a number...

journal_title：Medical physics

authors： Hill R,Mo Z,Haque M,Baldock C

更新日期：2009-09-01 00:00:00

abstract：:Anisotropy of dose distributions around 103Pd, 125I, and 192Ir sources for interstitial brachytherapy was examined. Dose rates around 125I models 6702 and 6711 and 192Ir sources were measured using lithium fluoride thermoluminescence dosimeters (LiF TLDs) in a water-equivalent, solid phantom. From these measured data ...

journal_title：Medical physics

authors： Nath R,Meigooni AS,Muench P,Melillo A

更新日期：1993-09-01 00:00:00

abstract：PURPOSE:Ablative hyperthermia (>55 °C) has been used as a definitive treatment for accessible solid tumors not amenable to surgery, whereas mild hyperthermia (40-45 °C) has been shown effective as an adjuvant for both radiotherapy and chemotherapy. An optimal mild hyperthermia treatment is spatially accurate, with prec...

journal_title：Medical physics

authors： Partanen A,Tillander M,Yarmolenko PS,Wood BJ,Dreher MR,Kohler MO

更新日期：2013-01-01 00:00:00

abstract：PURPOSE:The possible clinical applications which can be performed using a newly developed detector depend on the detector's characteristic performance in a number of metrics including the dynamic range, resolution, uniformity, and stability. The authors have evaluated a prototype energy resolved fast photon counting x-...

journal_title：Medical physics

authors： Cho HM,Barber WC,Ding H,Iwanczyk JS,Molloi S

更新日期：2014-09-01 00:00:00

abstract：PURPOSE:The authors investigate performance of thin-film cadmium telluride (CdTe) in detecting high-energy (6 MV) x rays. The utilization of this material has become technologically feasible only in recent years due to significant development in large area photovoltaic applications. METHODS:The CdTe film is combined w...

journal_title：Medical physics

authors： Parsai EI,Shvydka D,Kang J

更新日期：2010-08-01 00:00:00

abstract：:Preclinical experiments are carried out with approximately 20-30 microm wide, approximately 10 mm high parallel microbeams of hard, broad-"white"-spectrum x rays (approximately 50-600 keV) to investigate microbeam radiation therapy (MRT) of brain tumors in infants for whom other kinds of radiotherapy are inadequate an...

journal_title：Medical physics

authors： Bräuer-Krisch E,Bravin A,Lerch M,Rosenfeld A,Stepanek J,Di Michiel M,Laissue JA

更新日期：2003-04-01 00:00:00

abstract：PURPOSE:Periodic MV∕KV radiographs taken during volumetric modulated arc therapy (VMAT) for hypofractionated treatment provide guidance in intrafractional motion management. The choice of imaging frequency and timing are key components in delivering the desired dose while reducing associated overhead such as imaging do...

journal_title：Medical physics

authors： Zhang P,Hunt M,Happersett L,Cox B,Mageras G

更新日期：2012-09-01 00:00:00

abstract：PURPOSE:The purpose of the study is to investigate the characteristics of a two-dimensional (2D) liquid-filled ion chamber detector array, which is used for the verification of radiotherapy treatment plans that use small field sizes of up to 10 × 10 cm. METHODS:The device used in this study was Octavius 1000 SRS model...

journal_title：Medical physics

authors： Markovic M,Stathakis S,Mavroidis P,Jurkovic IA,Papanikolaou N

更新日期：2014-05-01 00:00:00

abstract：:A commercial optical system developed by Solid Photography, Inc., has been used to generate precise paraffin--polyethylene tissue compensators. A program with the objective of constructing a medical facility has been undertaken to access patient topology for treatment planning, tissue-compensator fabrication, and pati...

journal_title：Medical physics

authors： Lerch IA,Barish RJ,Stern H

更新日期：1978-11-01 00:00:00

abstract：PURPOSE:Using a new linear accelerator with high dose rate (800 MU/min), fast MLC motions (5.0 cm/s), fast gantry rotation (15 s/rotation), and 1 cm wide MLCs, we aimed to quantify the effects of complexity, arc number, and fractionation on interplay for breast and lung treatments under target motion. METHODS:To study...

journal_title：Medical physics

authors： Netherton T,Li Y,Nitsch P,Shaitelman S,Balter P,Gao S,Klopp A,Muruganandham M,Court L

更新日期：2018-06-01 00:00:00