A field-shaping multi-well avalanche detector for direct conversion amorphous selenium.

abstract：PURPOSE:Anomalous pixels may be defined as those pixels whose exposure response relationship is deviant from the typical, expected or calibrated response. A group of anomalous pixels may Result in visible correlated artifacts. Here we demonstrate an approach to identify anomalous pixels and correlated artifacts using f...

journal_title：Medical physics

authors： Dave J,Gingold E,Yorkston J,Bercha I,Goldman L,Walz-Flannigan A,Willis C

更新日期：2012-06-01 00:00:00

abstract：:The purposes of this study are: (i) to design field flattening filters for the Leipzig applicators of 2 and 3 cm of inner diameter with the source traveling parallel to the applicator contact surface, which are accessories of the microSelectron-HDR afterloader (Nucletron, Veenendaal, The Netherlands). These filters, m...

journal_title：Medical physics

authors： Granero D,Pérez-Calatayud J,Gimeno J,Ballester F,Casal E,Crispín V,van der Laarse R

更新日期：2008-02-01 00:00:00

abstract：:The method of magnetic resonance imaging (MRI) was an extension of nuclear magnetic resonance (NMR) spectroscopy that was enabled by computational systems capable of performing the Fast Fourier Transform. Initially, a diverse group of methods were proposed for producing images with NMR, with the multi-slice spin-warp ...

journal_title：Medical physics

authors： Clarke G

更新日期：2012-06-01 00:00:00

abstract：PURPOSE:To describe Acuros® CTS, a new software tool for rapidly and accurately estimating scatter in x-ray projection images by deterministically solving the linear Boltzmann transport equation (LBTE). METHODS:The LBTE describes the behavior of particles as they interact with an object across spatial, energy, and dir...

journal_title：Medical physics

authors： Maslowski A,Wang A,Sun M,Wareing T,Davis I,Star-Lack J

更新日期：2018-05-01 00:00:00

abstract：PURPOSE:To achieve more translatable preclinical research results, small animal irradiation needs to more closely simulate human radiotherapy. Although the clinical gold standard is intensity-modulated radiation therapy (IMRT), the direct translation of this method for small animals is impractical. In this study we des...

journal_title：Medical physics

authors： Woods K,Nguyen D,Neph R,Ruan D,O'Connor D,Sheng K

更新日期：2019-12-01 00:00:00

abstract：:A study of the objective imaging characteristics of a new asymmetric screen-film system is presented herein. The system is characterized by high x-ray absorption asymmetric screens, and a low-noise, high-contrast asymmetric film having near-zero crossover. Comparisons are made with the imaging characteristics of two w...

journal_title：Medical physics

authors： Van Metter R,Dickerson R

更新日期：1994-09-01 00:00:00

abstract：:The goal of this study was to develop a technique to distinguish benign and malignant breast lesions in secondarily digitized mammograms. A set of 51 mammograms (two views/patient) containing lesions of known pathology were evaluated using six different morphological descriptors: circularity, mu R/sigma R (where mu R ...

journal_title：Medical physics

authors： Pohlman S,Powell KA,Obuchowski NA,Chilcote WA,Grundfest-Broniatowski S

更新日期：1996-08-01 00:00:00

abstract：PURPOSE:Anatomical variations occur during head and neck (H&N) radiotherapy treatment. kV cone-beam computed tomography (CBCT) images can be used for daily dose monitoring to assess dose variations owing to anatomic changes. Deep learning methods (DLMs) have recently been proposed to generate pseudo-CT (pCT) from CBCT ...

journal_title：Medical physics

authors： Barateau A,De Crevoisier R,Largent A,Mylona E,Perichon N,Castelli J,Chajon E,Acosta O,Simon A,Nunes JC,Lafond C

更新日期：2020-10-01 00:00:00

abstract：PURPOSE:The authors have developed a system that monitors intrafractional target motion perpendicular to the treatment beam with the aid of radioopaque markers by means of separating kV image and megavoltage (MV) treatment field on a single flat-panel detector. METHODS:They equipped a research Siemens Artiste linear a...

journal_title：Medical physics

authors： Fast MF,Krauss A,Oelfke U,Nill S

更新日期：2012-01-01 00:00:00

abstract：:A scintillation dosemeter is calibrated for 90Sr/90Y beta rays from an ophthalmic applicator, using an extrapolation ionization chamber as a reference instrument. The calibration factor for the scintillation dosemeter agrees with that given by the manufacturer of the dosemeter within ca. 2%. The estimated overall unce...

journal_title：Medical physics

authors： Hakanen AT,Sipilä PM,Kosunen A

更新日期：2004-05-01 00:00:00

abstract：PURPOSE:We propose a new metric called Distance Discordance (DD), which is defined as the distance between two anatomic points from two moving images, which are co-located on some reference image, when deformed onto another reference image. METHODS:To demonstrate the concept of DD, we created a reference software phan...

journal_title：Medical physics

authors： Berns E

更新日期：2012-06-01 00:00:00

abstract：:The main purpose of this work is to demonstrate a practical means of determining the leaf transmission and scatter characteristics of a multileaf collimator (MLC) pertinent to the commissioning of dynamic intensity modulated radiotherapy, especially for the sweeping window technique. The data are necessary for the con...

journal_title：Medical physics

authors： Arnfield MR,Siebers JV,Kim JO,Wu Q,Keall PJ,Mohan R

更新日期：2000-10-01 00:00:00

abstract：:Interchange or transfer of radiographic techniques through measurement of penetration quality is discussed. The usefulness of this achievement is verified using an aluminum step wedge. Also, the procedure described provides a method for performance evaluation of kVp compensation on diagnostic x-ray installations. ...

journal_title：Medical physics

authors： Lin PJ

更新日期：1975-01-01 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：:An analytic expression is derived for the transmission of isotropic scattered radiation incident upon an ideal parallel grid. It is found that the expression for the transmission usually found in the literature overestimates the transmission by approximately a factor of two. ...

journal_title：Medical physics

authors： Siddon RL

更新日期：1981-11-01 00:00:00

abstract：PURPOSE:Body composition is known to be associated with many diseases including diabetes, cancers, and cardiovascular diseases. In this paper, we developed a fully automatic body tissue decomposition procedure to segment three major compartments that are related to body composition analysis - subcutaneous adipose tissu...

journal_title：Medical physics

authors： Fu Y,Ippolito JE,Ludwig DR,Nizamuddin R,Li HH,Yang D

更新日期：2020-11-01 00:00:00

abstract：PURPOSE:To investigate the accuracy of output factor measurements using a commercial (Exradin W1, SI) and a prototype, "in-house" developed, plastic scintillation dosimeter (PSD) in small photon fields. METHODS:Repetitive detector-specific output factor OFdet measurements were performed in water (parallel to the CAX) ...

journal_title：Medical physics

authors： Papaconstadopoulos P,Archambault L,Seuntjens J

更新日期：2017-02-01 00:00:00

abstract：PURPOSE:RapidArc is routinely used for stereotactic radiotherapy for lung cancer. While treatment dose is optimized and calculated on a static CT image, the motion of the target in conjunction with the motion of the MLC may Result in a delivered dose deviating from the planed dose. In this study, we investigate the dos...

journal_title：Medical physics

authors： Zou J,Yin L,Shen J,Corradetti M,Kirk M,Rengan R,Teo BK

更新日期：2012-06-01 00:00:00

abstract：PURPOSE:We investigated the feasibility of using simpler methods than manual whole-organ volume-of-interest (VOI) definition to estimate the organ activity concentration in single photon emission computed tomography (SPECT) in cases where the activity in the organ can be assumed to be uniformly distributed on the scale...

journal_title：Medical physics

authors： Vicente EM,Lodge MA,Rowe SP,Wahl RL,Frey EC

更新日期：2017-05-01 00:00:00

abstract：PURPOSE:To develop a novel three-dimensional (3D) hybrid-encoding framework using compressed sensing (CS) and Toeplitz encoding with variable phase-scrambled radio-frequency (RF) excitation, which has the following advantages: low power deposition of RF pulses, reduction of the signal dynamic range, no additional hardw...

journal_title：Medical physics

authors： Wang H,Liang D,Su S,King KF,Chang Y,Liu X,Zheng H,Ying L

更新日期：2020-04-01 00:00:00

abstract：:The half-life of two I-125 encapsulated clinical seeds was measured with a Si(Li) semiconductor detector. Two measurements of each seed yielded an average half-life of 59.56 +/- 0.17 days. The results are discussed in terms of the influence of possible I-126 contamination and leakage of I-125 activity through encapsul...

journal_title：Medical physics

authors： Kubo H

更新日期：1983-11-01 00:00:00

abstract：PURPOSE:Intensity modulated proton therapy (IMPT) of head and neck (H&N) cancer patients may be improved by plan adaptation. The decision to adapt the treatment plan based on a dose recalculation on the current anatomy requires a diagnostic quality computed tomography (CT) scan of the patient. As gantry-mounted cone be...

journal_title：Medical physics

authors： Landry G,Nijhuis R,Dedes G,Handrack J,Thieke C,Janssens G,Orban de Xivry J,Reiner M,Kamp F,Wilkens JJ,Paganelli C,Riboldi M,Baroni G,Ganswindt U,Belka C,Parodi K

更新日期：2015-03-01 00:00:00

abstract：:The Anisotropic Analytical Algorithm (AAA) of the Varian Eclipse treatment planning system calculates absolute dose for a variety of beam settings including those with an enhanced dynamic wedge (EDW). This algorithm has gone through a number of version updates since it was first released in July 2005. Previous version...

journal_title：Medical physics

authors： Salomons G,Kerr A,Mei X,Patel D

更新日期：2008-07-01 00:00:00

abstract：PURPOSE:The authors describe a design for prepatient region of interest attenuators (ROIAs) to reduce dose area product (DAP) for clinical use. The authors describe a model to predict DAP values from x-ray technique parameters recorded during a clinical procedure for image sequences obtained in the presence or absence ...

journal_title：Medical physics

authors： Robert N,Watt KN,Rochette S,Desponds L,Vaillant R,Rowlands JA

更新日期：2015-01-01 00:00:00

abstract：PURPOSE:By means of Monte Carlo (MC) simulations and indirect measurements, we have evaluated the maximum dose rates achievable with conventional x-ray tubes and related them to FLASH therapy dose rates of >40 Gy/s. METHODS:Monte Carlo models of two 160 kV x-ray tubes, the 3-kW MXR-160/22 and the 6-kW MXR-165, were bu...

journal_title：Medical physics

authors： Bazalova-Carter M,Esplen N

更新日期：2019-12-01 00:00:00

abstract：:We employed an elastic reservoir filled with tissue-equivalent fluid as an x-ray beam filter for exposure equalization. The filter is designed to be placed between the upper compression plate and the breast. During compression, it will conform to the shape of the peripheral region of the breast and fill the space betw...

journal_title：Medical physics

authors： Lam KL,Chan HP

更新日期：1990-03-01 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

authors： Baydush AH,Marks LB,Das SK

更新日期：2004-08-01 00:00:00

abstract：PURPOSE:Normal patient databases (NPDs) are used to distinguish between normal and abnormal perfusion in SPECT myocardial perfusion imaging (MPI) and have gained wide acceptance in the clinical environment, yet there are limitations to this approach. This study introduces a template-based method for semi-quantitative M...

journal_title：Medical physics

authors： Hughes T,Shcherbinin S,Celler A

更新日期：2011-07-01 00:00:00

abstract：:The gamma index is a tool that compares a dose distribution with a reference distribution by combining dose-difference and distance-to-agreement criteria. It has been widely used for ten years despite its high computational cost. This cost is due to both a search process for each reference point and the necessity to r...

journal_title：Medical physics

authors： Blanpain B,Mercier D

更新日期：2009-03-01 00:00:00

abstract：PURPOSE:Tumor motion during radiotherapy can cause a reduction in target dose coverage and an increase in healthy tissue exposure. Tumor motion is not strictly translational and often exhibits complex six degree-of-freedom (6DoF) translational and rotational motion. Although the dosimetric impact of prostate tumor tran...

journal_title：Medical physics

authors： Shi K,Dipuglia A,Booth J,Alnaghy S,Kyme A,Keall P,Nguyen DT

更新日期：2020-12-01 00:00:00