Conceptual design of beryllium targets for the generation of neutron beams for radiation therapy by the (p,n) reaction.

abstract：:A method for the in vivo determination of the isocenter dose, Diso, and mid-plane dose, Dm, using the transmitted signal St measured by 25 central pixels of an aSi-based EPID is here reported. The method has been applied to check the conformal radiotherapy of pelvic tumors and supplies accurate in vivo dosimetry avoid...

journal_title：Medical physics

authors： Piermattei A,Fidanzio A,Stimato G,Azario L,Grimaldi L,D'Onofrio G,Cilla S,Balducci M,Gambacorta MA,Di Napoli N,Cellini N

更新日期：2006-11-01 00:00:00

abstract：PURPOSE:The aim of this work is to investigate the predictive power of a common conventional intensity modulated radiation therapy (IMRT) quality assurance (QA) performance metric, the gamma passing rate (%GP), through the analysis of the sensitivity and of the correlation between %GP and different dose discrepancies b...

journal_title：Medical physics

authors： Stasi M,Bresciani S,Miranti A,Maggio A,Sapino V,Gabriele P

更新日期：2012-12-01 00:00:00

abstract：PURPOSE:Volumetric x-ray microcomputed tomography (CT) can be employed in a variety of quantitative research applications such as image-guided interventions or characterization of medical devices. To ensure the highest geometric fidelity of images for these applications, a phantom and image processing algorithm have be...

journal_title：Medical physics

authors： Waring CS,Bax JS,Samarabandu A,Holdsworth DW,Fenster A,Lacefield JC

更新日期：2012-10-01 00:00:00

abstract：PURPOSE:Quantitative SPECT imaging is limited by many factors, including penetration of high energy photons through the collimator. Even small peaks of high energy yield extensive contamination in the photopeak energy window. Rotating slat collimators typically offer a 40- to 50-fold increase in geometric detection eff...

journal_title：Medical physics

authors： Van Holen R,Staelens S,Vandenberghe S

更新日期：2009-09-01 00:00:00

abstract：PURPOSE:Removal of the linear accelerator (linac) flattening filter enables a high rate of dose deposition with reduced treatment time. When used for megavoltage imaging, an unflat beam has reduced primary beam scatter resulting in sharper images. In fluoroscopic imaging mode, the unflat beam has higher photon count pe...

journal_title：Medical physics

authors： Christensen JD,Kirichenko A,Gayou O

更新日期：2013-08-01 00:00:00

abstract：:The paper presents a theoretical derivation of the photon fluence simulation efficiency in photon beam treatment head simulations without and with bremsstrahlung splitting. The expressions obtained provide a rigorous explanation of the efficiency dependence on scoring zone size and splitting number and explain the lar...

journal_title：Medical physics

authors： Kawrakow I

更新日期：2005-07-01 00:00:00

abstract：:Cone beam computed tomography (CBCT) is a relatively new patient imaging technique that has proved invaluable for treatment target verification and patient positioning during image-guided radiotherapy (IGRT). It has been shown that CBCT results in additional dose to bone that may amount to 10% of the prescribed dose. ...

journal_title：Medical physics

authors： Walters BR,Ding GX,Kramer R,Kawrakow I

更新日期：2009-07-01 00:00:00

abstract：:We present a technique for semiautomated segmentation of human prostates using suprapubic ultrasound (US) images. In this approach, a speckle reducing anisotropic diffusion (SRAD) is applied to enhance the images and the instantaneous coefficient of variation (ICOV) is utilized for edge detection. Segmentation is acco...

journal_title：Medical physics

authors： Yu Y,Molloy JA,Acton ST

更新日期：2004-12-01 00:00:00

abstract：PURPOSE:Real-time sub-millimeter head motion compensation during frameless SRS delivery has the potential to achieve the accuracy of frame-based SRS while being significantly less invasive. Previously, we demonstrated real-time 6D head motion monitoring using an optical camera, however, at the time we were limited to o...

journal_title：Medical physics

authors： Belcher AH,Wiersma RD

更新日期：2012-06-01 00:00:00

abstract：:Computer algorithms for rotational therapy beams, in most cases, perform dose calculations by summing stored fixed beam data at finite angular steps. Such an algorithm, based on the Bentley beam model, was evaluated by comparing calculations with measured data for an 18-MV x-ray beam. Measurements were made in a speci...

journal_title：Medical physics

authors： Kurup RG,Hogstrom KR,Hwang CC

更新日期：1987-11-01 00:00:00

abstract：PURPOSE:The recent development of multifocal stereotactic radiosurgery (SRS) using a single isocenter volumetric modulated arc theory (VMAT) technique warrants a re-examination of the quality assurance (QA) tolerances for routine mechanical QA recommended by the American Association of Physicists in Medicine Task Group...

journal_title：Medical physics

authors： Faught AM,Trager M,Yin FF,Kirkpatrick J,Adamson J

更新日期：2016-10-01 00:00:00

abstract：PURPOSE:The management of thoracic malignancies with radiation therapy is complicated by continuous target motion. In this study, a real time motion analysis approach is proposed to improve the accuracy of patient setup. METHODS:For 11 lung cancer patients a long training fluoroscopy was acquired before the first trea...

journal_title：Medical physics

authors： Chen T,Jabbour SK,Qin S,Haffty BG,Yue N

更新日期：2013-04-01 00:00:00

abstract：:Projected light fields are used on treatment simulators and teletherapy treatment units to delineate the size and position of the radiation beam. Any discrepancy between these fields will lead to a systematic field placement error, with possibly serious implications with regard to the accuracy of the delivered dose di...

journal_title：Medical physics

authors： Luchka K,Chen D,Shalev S,Gluhchev G,Rajapakshe R

更新日期：1996-07-01 00:00:00

abstract：PURPOSE:To evaluate the treatment planning system (TPS) performance of the ZAP-X stereotactic radiosurgery (SRS) system through nondosimetric, dosimetric, and end-to-end (E2E) tests. METHODS:A comprehensive set of TPS commissioning and validation tests were developed using published guidelines. Nondosimetric validatio...

journal_title：Medical physics

authors： Srivastava SP,Jani SS,Pinnaduwage DS,Yan X,Rogers L,Barranco FD,Barani IJ,Sorensen S

更新日期：2021-01-28 00:00:00

abstract：:Determination of the relaxation times T1 and T2 which are important for tissue characterization generally requires the use of different pulse sequences in magnetic resonance imaging. In this study, a new pulse sequence which facilitates simultaneous determination of the T1 and T2 times is presented. Determination take...

journal_title：Medical physics

authors： Graumann R,Fischer H,Oppelt A

更新日期：1986-09-01 00:00:00

abstract：PURPOSE:To compare and evaluate intensity-based registration methods for computation of serial x-ray mammogram correspondence. METHODS:X-ray mammograms were simulated from MRIs of 20 women using finite element methods for modeling breast compressions and employing a MRI/x-ray appearance change model. The parameter con...

journal_title：Medical physics

authors： Pinto Pereira SM,Hipwell JH,McCormack VA,Tanner C,Moss SM,Wilkinson LS,Khoo LA,Pagliari C,Skippage PL,Kliger CJ,Hawkes DJ,Silva IM

更新日期：2010-09-01 00:00:00

abstract：:The purpose of this study is to develop a 4D inverse planning strategy capable of controlling the appearance of the implanted fiducial(s) in segmented IMRT fields for cine MV or combined MV/kV image-guided IMRT. This work is focused on enhancing the visibility of the implanted fiducial(s) in 4D IMRT inverse planning, ...

journal_title：Medical physics

authors： Ma Y,Lee L,Keshet O,Keall P,Xing L

更新日期：2009-06-01 00:00:00

abstract：:The dynamic range of the gray level of a digital image is limited by the noise it contains. Two statistical methods called "runs test" and "join-count statistic" are used to measure the noise level in a digital image. A residual image is formed by subtracting an original image from its smoothed version. Theoretically,...

journal_title：Medical physics

authors： Chuang KS,Huang HK

更新日期：1993-01-01 00:00:00

abstract：:Wireless capsule endoscopy (WCE) is a powerful tool for medical screening and diagnosis, where a small capsule is swallowed and moved by means of natural peristalsis and gravity through the human gastrointestinal (GI) tract. The camera-integrated capsule allows for visualization of the small intestine, a region which ...

journal_title：Medical physics

authors： Shamsudhin N,Zverev VI,Keller H,Pane S,Egolf PW,Nelson BJ,Tishin AM

更新日期：2017-08-01 00:00:00

abstract：PURPOSE:To develop a probabilistic treatment planning (PTP) method which is robust to systematic patient setup errors and to compare PTP plans with plans generated using a planning target volume (PTV) margin optimized to give the same target coverage probability as the PTP plan. METHODS:Plans adhering to the RTOG-0126...

journal_title：Medical physics

authors： Moore JA,Gordon JJ,Anscher M,Silva J,Siebers JV

更新日期：2012-02-01 00:00:00

abstract：:One limitation to the widespread implementation of Monte Carlo (MC) patient dose-calculation algorithms for radiotherapy is the lack of a general and accurate source model of the accelerator radiation source. Our aim in this work is to investigate the sensitivity of the photon-beam subsource distributions in a MC sour...

journal_title：Medical physics

authors： Fix MK,Keall PJ,Siebers JV

更新日期：2005-04-01 00:00:00

abstract：:A micro-angiographic detector was designed and its performance was previously tested to evaluate its feasibility as an improvement over current x-ray detectors for neuro-interventional imaging. The detector was shown to have a modulation transfer function value of about 2% at the Nyquist frequency of 10 cycles/mm and ...

journal_title：Medical physics

authors： Ganguly A,Rudin S,Bednarek DR,Hoffmann KR

更新日期：2003-11-01 00:00:00

abstract：PURPOSE:In C-arm computed tomography (CT), the field of view (FOV) is often not sufficient to acquire certain anatomical structures, e.g., a full hip or thorax. Proposed methods to extend the FOV use a fixed detector displacement and a 360° scan range to double the radius of the FOV. These trajectories are designed for...

journal_title：Medical physics

authors： Herbst M,Schebesch F,Berger M,Choi JH,Fahrig R,Hornegger J,Maier A

更新日期：2015-05-01 00:00:00

abstract：PURPOSE:Radiotherapy, especially with charged particles, is sensitive to executional and preparational uncertainties that propagate to uncertainty in dose and plan quality indicators, for example, dose-volume histograms (DVHs). Current approaches to quantify and mitigate such uncertainties rely on explicitly computed e...

journal_title：Medical physics

authors： Wahl N,Hennig P,Wieser HP,Bangert M

更新日期：2020-10-01 00:00:00

abstract：:This paper examines the distributions of the SAR (specific absorption rate) ratio and temperature elevation when an ultrasound beam propagates through the interface of muscle and bone. This interface is regarded as a flat boundary to partition the energy of the ultrasound beam, and the analytical solution of temperatu...

journal_title：Medical physics

authors： Lin WL,Liauh CT,Chen YY,Liu HC,Shieh MJ

更新日期：2000-05-01 00:00:00

abstract：PURPOSE:Colitis refers to inflammation of the inner lining of the colon that is frequently associated with infection and allergic reactions. In this paper, we propose deep convolutional neural networks methods for lesion-level colitis detection and a support vector machine (SVM) classifier for patient-level colitis dia...

journal_title：Medical physics

authors： Liu J,Wang D,Lu L,Wei Z,Kim L,Turkbey EB,Sahiner B,Petrick NA,Summers RM

更新日期：2017-09-01 00:00:00

abstract：:Radiographic magnification is often employed in mammography to improve detection of small anatomical details of clinical interest, such as microcalcifications. The image size depends on the conventional magnification factor, on the focal spot size, and on the x-ray angulation. In this paper magnification effects are i...

journal_title：Medical physics

authors： Schiabel H,Ventura A,Frère AF

更新日期：1994-02-01 00:00:00

abstract：PURPOSE:High-dose-rate brachytherapy (HDR-BT) is a treatment option for malignant skin diseases compared to external beam radiation therapy, HDR-BT provides improved target coverage, better organ sparing, and has comparable treatment times. This is especially true for large clinical targets with complex topologies. To ...

journal_title：Medical physics

authors： Guthier CV,Devlin PM,Harris TC,O'Farrell DA,Cormack RA,Buzurovic I

更新日期：2020-03-01 00:00:00

abstract：PURPOSE:The quality of a treatment plan for stereotactic body radiotherapy (SBRT) depends on an experience of each treatment planner. Therefore, the treatment plans are subjectively determined by comparison of several treatment plans developed by time consuming iterative manners, while considering the benefit to a tumo...

journal_title：Medical physics

authors： Magome T,Arimura H,Shioyama Y,Mizoguchi A,Tokunaga C,Nakamura K,Honda H,Ohki M,Toyofuku F,Hirata H

更新日期：2012-06-01 00:00:00

abstract：:Magnetic resonance (MR) measurements of relaxation times and diffusion coefficient in tissue have been demonstrated to be sensitive to biological changes induced by radiation therapy. We are currently using mouse models of human glioblastoma multiforme (GBM) to study tumour response to ionizing radiation by MRI at 9.4...

journal_title：Medical physics

authors： Larocque M,Syme A,Fallone BG

更新日期：2008-07-01 00:00:00