Bremsstrahlung production at 50 MeV in different target materials and configurations.

abstract：PURPOSE:The purpose of this work was to investigate the use of an experimental complementary metal-oxide-semiconductor (CMOS) active pixel sensor (APS) for tracking of moving fiducial markers during radiotherapy. METHODS:The APS has an active area of 5.4 × 5.4 cm and maximum full frame read-out rate of 20 frame s(-1),...

journal_title：Medical physics

authors： Osmond JP,Zin HM,Harris EJ,Lupica G,Allinson NM,Evans PM

更新日期：2011-11-01 00:00:00

abstract：:System modeling is used to investigate the effect of various system parameters on the image quality in CCD-based x-ray imaging systems. The systems considered consist of a typical phosphor-based scintillating screen coupled to a CCD through lens or fiberoptic taper. Two applications, chest radiography and mammography,...

journal_title：Medical physics

authors： Hejazi S,Trauernicht DP

更新日期：1997-02-01 00:00:00

abstract：:Electron-beam characteristics of a Philips SL25 linear accelerator have been studied. Central-axis percentage depth doses, cross-beam profiles and beam output factors of 6-, 10-, and 20-MeV beams, selected from the available energy range of 4 to 22 MeV, are reported in this paper. The main thrust of this work is to de...

journal_title：Medical physics

authors： Rashid H,Islam MK,Gaballa H,Rosenow UF,Ting JY

更新日期：1990-07-01 00:00:00

abstract：:This article is the first in a series on the calculation of electron dose using multiple-scattering theory. In it we develop a unified theory, which we term Gaussian multiple-scattering theory, starting from a number of contributions already in the literature: the Fermi-Eyges multiple-scattering theory, the Yang path ...

journal_title：Medical physics

authors： Jette D

更新日期：1988-03-01 00:00:00

abstract：:The objective is to understand the differences in the lesion formation processes between microwave and high-intensity focused ultrasound (HIFU) ablation. The lesions formed by microwaves and HIFU were real-time monitored and compared using transparent tissue-mimicking phantoms at 60 and 70 W of driving electrical powe...

journal_title：Medical physics

authors： Chen WS,Wu CC,Fang HY,Liu HL

更新日期：2006-05-01 00:00:00

abstract：PURPOSE:The paper presents a complete computer-aided detection (CAD) system for the detection of lung nodules in computed tomography images. A new mixed feature selection and classification methodology is applied for the first time on a difficult medical image analysis problem. METHODS:The CAD system was trained and t...

journal_title：Medical physics

authors： Tan M,Deklerck R,Jansen B,Bister M,Cornelis J

更新日期：2011-10-01 00:00:00

abstract：:The widespread application of positron emission tomography (PET) in clinical oncology has driven this imaging technology into a number of new research and clinical arenas. Increasing numbers of patient scans have led to an urgent need for efficient data handling and the development of new image analysis techniques to ...

journal_title：Medical physics

authors： Montgomery DW,Amira A,Zaidi H

更新日期：2007-02-01 00:00:00

abstract：PURPOSE:To investigate how x-ray tube projection angle affects organ and effective doses to patients undergoing a CT examination on a cone beam scanner. METHODS:The authors investigated two cone beam CT systems that use a flat panel detector to capture the x-ray pattern transmitted through patients. One system had the...

journal_title：Medical physics

authors： He W,Huda W,Magill D,Tavrides E,Yao H

更新日期：2010-05-01 00:00:00

abstract：PURPOSE:Severe artifacts in kilovoltage-CT simulation images caused by large metallic implants can significantly degrade the conspicuity and apparent CT Hounsfield number of targets and anatomic structures, jeopardize the confidence of anatomical segmentation, and introduce inaccuracies into the radiation therapy treat...

journal_title：Medical physics

authors： Li H,Noel C,Chen H,Harold Li H,Low D,Moore K,Klahr P,Michalski J,Gay HA,Thorstad W,Mutic S

更新日期：2012-12-01 00:00:00

abstract：:Intensity Modulated Arc Therapy (IMAT) is a rotational variant of Intensity Modulated Radiation Therapy (IMRT) that can be implemented with or without angular dose rate optimization. The purpose of this study is to determine the inter-relationship among arc range, Multi-Leaf Collimator (MLC) leaf positions and angular...

journal_title：Medical physics

authors： Oliver M,Chen J,Wong E

更新日期：2008-07-01 00:00:00

abstract：PURPOSE:Breast density is a significant breast cancer risk factor. Although various methods are used to estimate breast density, there is no standard measurement for this important factor. The authors are developing a breast density standardization method for use in full field digital mammography (FFDM). The approach c...

journal_title：Medical physics

authors： Heine JJ,Cao K,Beam C

更新日期：2009-12-01 00:00:00

abstract：PURPOSE:In a recent paper by Bouchard et al. [Med. Phys. 36(10), 4654-4663 (2009)], a theoretical model of quality correction factors for idealistic so-called plan-class specific reference (PCSR) fields was proposed. The reasoning was founded on the definition of PCSR fields made earlier by Alfonso et al. [Med. Phys. 3...

journal_title：Medical physics

authors： Bouchard H,Seuntjens J,Palmans H

更新日期：2012-03-01 00:00:00

abstract：:The last 50 years have seen great advances in the accuracy of external beam radiation therapy. Geometrical uncertainties have been reduced from a centimeter or more in presimulation, skin-mark guided days to 1-2 mm in today's image-guided radiation therapy treatments. Medical physicists, with the support and guidance ...

journal_title：Medical physics

authors： Yorke ED,Keall P,Verhaegen F

更新日期：2008-03-01 00:00:00

abstract：PURPOSE:To generate hybrid VMAT-IMRT treatment plans by utilizing an IMRT beam-angle-optimality (BAO) search under a commercially available TPS without the aid of custom optimization software or high performance computing. METHODS:The high dose modulation provided by IMRT beams can be exploited to improve the quality ...

journal_title：Medical physics

authors： Schulze D,Ionascu D,Tyagi N

更新日期：2012-06-01 00:00:00

abstract：PURPOSE:To analyze the noise performance of the edge illumination phase-based x-ray imaging technique when applying "single-shot" phase retrieval. The latter consists in applying a sample-specific low-pass filter to the raw data, leading to "hybrid" images in which phase and attenuation contrast are merged with each ot...

journal_title：Medical physics

authors： Hagen CK,Roche I Morgó O,Olivo A

更新日期：2020-09-01 00:00:00

abstract：PURPOSE:Water equivalent diameter (WED) is the preferred surrogate for patient size in CT. It is better than geometric size surrogates and patient weight/height/BMI/age because it correlates the best with x-ray attenuation. The administration of oral/IV contrast agents increases a patient's attenuation and should there...

journal_title：Medical physics

authors： Viggiano B,Rose S,Szczykutowicz TP

更新日期：2021-01-13 00:00:00

abstract：PURPOSE:In this article, the authors propose a new gold standard data set for the validation of two-dimensional/three-dimensional (2D/3D) and 3D/3D image registration algorithms. METHODS:A gold standard data set was produced using a fresh cadaver pig head with attached fiducial markers. The authors used several imagin...

journal_title：Medical physics

authors： Pawiro SA,Markelj P,Pernus F,Gendrin C,Figl M,Weber C,Kainberger F,Nöbauer-Huhmann I,Bergmeister H,Stock M,Georg D,Bergmann H,Birkfellner W

更新日期：2011-03-01 00:00:00

abstract：PURPOSE:Consistency verification between the data from treatment planning system (TPS), record and verification system (R&V), and delivered recorder with visual inspection is time consuming and subject to human error. The purpose of this work is to develop a software tool to automatically perform such verifications. M...

journal_title：Medical physics

authors： Chen G,Li X

更新日期：2012-06-01 00:00:00

abstract：PURPOSE:The aim of this study was to use MRI gel dosimetry to determine the dose profile of 50kV MAGNUM® X-ray tube, MOXTEK Inc., in order to calibrate small solid dosimeters of alanine, tooth enamel and LiF-TLDs, commonly used in clinical quality assurance and datation dosimetry. METHODS:MAGIC-f polymer gel was kept ...

journal_title：Medical physics

authors： Schwarcke M,Marques T,Nicolucci P,Filho OB

更新日期：2012-06-01 00:00:00

abstract：:The relatively precise placement of brachytherapy sources afforded by stereotactic frames for brain implants is not generally achievable for other sites, which lack the fixed geometry of the cranium and its contents. An exception is a source-containing rigid mold that delivers brachytherapy when inserted securely in a...

journal_title：Medical physics

authors： Anderson LL,Zlotolow IM,McCormick B,Harrison LB

更新日期：1995-03-01 00:00:00

abstract：PURPOSE:To quantify the inter fraction variation of spatial location of high dose regions of OARs in MR-image based cervix brachytherapy using rigid registration algorithm. METHODS:Retrospective analysis of 27 previously treated patients under EMBRACE multi-centric trial was evaluated. Each patient had two application...

journal_title：Medical physics

authors： Swamidas J,Mahantshetty U,Deshpande D,Shrivastava S

更新日期：2012-06-01 00:00:00

abstract：PURPOSE:An original radionuclide calibrator method for activity determination is presented. The method could be used for intercomparison surveys for short half-life radioactive sources used in Nuclear Medicine, such as(99m)Tc or most positron emission tomography radiopharmaceuticals. METHODS:By evaluation of the resul...

journal_title：Medical physics

authors： Oliveira PA,Santos JA

更新日期：2014-07-01 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：PURPOSE:The limited-angle intrafractional verification (LIVE) system was developed to track tumor movement during stereotactic body radiation therapy (SBRT). However, the four-dimensional (4D) MV/kV imaging procedure results in additional radiation dose to patients. This study is to quantify imaging radiation dose from...

journal_title：Medical physics

authors： Ding GX,Zhang Y,Ren L

更新日期：2019-06-01 00:00:00

abstract：:IMRT treatment plans for step-and-shoot delivery have traditionally been produced through the optimization of intensity distributions (or maps) for each beam angle. The optimization step is followed by the application of a leaf-sequencing algorithm that translates each intensity map into a set of deliverable aperture ...

journal_title：Medical physics

authors： Shepard DM,Earl MA,Li XA,Naqvi S,Yu C

更新日期：2002-06-01 00:00:00

abstract：PURPOSE:To determine the feasibility and potential utility of cone beam CT on breast biopsies. METHODS:CBCT simulations were done with a setup which emulates an MX-20 digital specimen radiography system (Faxitron X-Ray Corporation, Chicago, IL), albeit a DQE = 1 was assumed. The phantom consisted of a 5mm diameter cyl...

journal_title：Medical physics

authors： Laamanen C,LeClair R

更新日期：2012-07-01 00:00:00

abstract：PURPOSE:Radiation therapy is often delivered by multiple sequential treatment plans. For an accurate radiobiological evaluation of the overall treatment, fractionation corrections to each dose distribution must be applied before summing the three-dimensional dose matrix of each plan since the simpler approach of perfor...

journal_title：Medical physics

authors： Mavroidis P,Ferreira BC,Papanikolaou N,Lopes Mdo C

更新日期：2013-03-01 00:00:00

abstract：PURPOSE:In recent years, laser-based acceleration of charged particles has rapidly progressed and medical applications, e.g., in radiotherapy, might become feasible in the coming decade. Requirements are monoenergetic particle beams with long-term stable and reproducible properties as well as sufficient particle intens...

journal_title：Medical physics

authors： Beyreuther E,Enghardt W,Kaluza M,Karsch L,Laschinsky L,Lessmann E,Nicolai M,Pawelke J,Richter C,Sauerbrey R,Schlenvoigt HP,Baumann M

更新日期：2010-04-01 00:00:00

abstract：PURPOSE:The determination of absorbed dose to water from external beam radiotherapy using radiation detectors is currently rooted in calibration protocols that do not account for modulations encountered in patient-specific deliveries. Detector response in composite clinical fields has not been extensively studied due t...

journal_title：Medical physics

authors： Desai VK,Labby ZE,Hyun MA,DeWerd LA,Culberson WS

更新日期：2019-02-01 00:00:00

abstract：PURPOSE:The nonlocal influence from distant magnetization will affect the magnetic field at a voxel in question. Existing reports on BOLD simulation only consider vasculature inside a single voxel, thus omitting the contribution from the surrounding regions. In this article, the authors study the effect of the surround...

journal_title：Medical physics

authors： Chen Z,Caprihan A,Calhoun V

更新日期：2010-04-01 00:00:00