Transverse axial film tomography with a therapy simulator.

abstract：:Results of an 18-alternative forced-choice experiment have shown that observers were capable of detecting a signal with a contrast of 1 in terms of 10-bit data which were displayed on a CRT monitor with an 8-bit video generator and a window width setting of 1024. We investigated the conditions under which 10-bit signa...

journal_title：Medical physics

authors： Giger ML,Ohara K,Doi K

更新日期：1986-05-01 00:00:00

abstract：:An optimization analysis of digital fluoroscopy has been carried out using (signal/noise)2/dose as a figure of merit. Three signal detection tasks have been considered: (i) small iodine-containing blood vessels; (ii) regions of fat; and (iii) microcalcifications. The effects of x-ray beam filtration and kilovoltage on...

journal_title：Medical physics

authors： Zamenhof RG

更新日期：1982-09-01 00:00:00

abstract：PURPOSE:Commercially available fillable plastic inserts used in positron emission tomography phantoms usually have thick plastic walls, separating their content from the background activity. These "cold" walls can modify the intensity values of neighboring active regions due to the partial volume effect, resulting in e...

journal_title：Medical physics

authors： Berthon B,Marshall C,Edwards A,Evans M,Spezi E

更新日期：2013-08-01 00:00:00

abstract：PURPOSE:A long-standing conundrum is why photoacoustic tomography (PAT) possesses the unique ability to produce images devoid of speckle artifacts while all other coherent imaging technologies do not. METHODS:In this paper, we explain the inherent mechanism that suppresses speckle in PAT, and the analysis was validate...

journal_title：Medical physics

authors： Guo Z,Li L,Wang LV

更新日期：2009-09-01 00:00:00

abstract：:Teletherapy with high linear energy transfer radiations (LET), perhaps more than with low LET types, requires careful beam collimation to limit effects to normal structures. Intensity modulated techniques may also hold promise in this regard. Accordingly, a remote computer-controlled, high-resolution multileaf collima...

journal_title：Medical physics

authors： Farr JB,Maughan RL,Yudelev M,Blosser E,Brandon J,Horste T,Forman JD

更新日期：2007-09-01 00:00:00

abstract：PURPOSE:Accurate segmentation of lungs with severe interstitial lung disease (ILD) in thoracic computed tomography (CT) is an important and difficult task in the development of computer-aided diagnosis (CAD) systems. Therefore, we developed in this study a texture analysis-based method for accurate segmentation of lung...

journal_title：Medical physics

authors： Wang J,Li F,Li Q

更新日期：2009-10-01 00:00:00

abstract：PURPOSE:Potential collision between the patient∕couch and the gantry could delay the start of the treatment and reduce clinical efficiency. The ability to accurately detect possible collisions during the treatment planning phase is desired. Such collision detection should account for the specific proton gantry design, ...

journal_title：Medical physics

authors： Zou W,Lin H,Plastaras JP,Wang H,Bui V,Vapiwala N,McDonough J,Tochner Z,Both S

更新日期：2012-11-01 00:00:00

abstract：:The dissemination of scientific advances has changed little since the first peer-reviewed journal was published in 1665 - that is, until this past decade. The print journal, delivered by mail and stored on office shelves and in library reading rooms around the world, has been transformed by immediate, on-demand access...

journal_title：Medical physics

authors： Armato S,Hendee W,Marshall C,Curran B

更新日期：2012-06-01 00:00:00

abstract：:Proton NMR spectroscopy was applied to quantitate the measurement of total body water/fat distributions in vivo. A special MR protocol was developed to excite a thick slab of tissue and display the magnitude NMR spectrum of the collected response signal. Very short echo time TE (8 ms) and long repetition time TR (4000...

journal_title：Medical physics

authors： Sobol WT,Elster AD,Hinson WH,Chwals WJ

更新日期：1992-01-01 00:00:00

abstract：:Ultrasound has been the greatest imaging modality worldwide for many years by equipment purchase value and by number of machines and examinations. It is becoming increasingly the front end imaging modality; serving often as an extension of the physician's fingers. We believe that at the other extreme, high-end systems...

journal_title：Medical physics

authors： Carson PL,Fenster A

更新日期：2009-02-01 00:00:00

abstract：:We designed a questionnaire to be filled out by the physicist at the time of planning treatment with the aid of a computer in order to assess what was learned during the course of the planning session. We analyzed the results to gauge the impact of the 70 treatment planning sessions conducted during the one month peri...

journal_title：Medical physics

authors： Doppke KP,Goitein M

更新日期：1988-03-01 00:00:00

abstract：:Many problems in physics involve imaging objects with high spatial frequency content in a limited amount of time. The limitation of available experimental data leads to the infamous problem of diffraction limited data which manifests itself by causing ringing in the image. This ringing is due to the interference pheno...

journal_title：Medical physics

authors： Haacke EM,Liang ZP,Izen SH

更新日期：1989-05-01 00:00:00

abstract：:The measurement of output factors for small fields is challenging and can lead to large dose errors in patient treatments if corrections for detector size and scatter from high-Z material are not applied. Due to its high spatial resolution and near tissue equivalence, GAFCHROMIC® film potentially provides a correction...

journal_title：Medical physics

authors： Vandervoort E,La Russa D,Ploquin N,Kadir IAE,Szanto J

更新日期：2012-07-01 00:00:00

abstract：PURPOSE:The presence of respiratory motion during radiation treatment leads to degradation of the expected dose distribution, both for target coverage and healthy tissue sparing, particularly for techniques like pencil beam scanning proton therapy which have dynamic delivery systems. While tools exist to estimate this ...

journal_title：Medical physics

authors： Pepin MD,Tryggestad E,Wan Chan Tseung HS,Johnson JE,Herman MG,Beltran C

更新日期：2018-11-01 00:00:00

abstract：:A proton dose computational algorithm, performing an analytical superposition of infinitely narrow proton beamlets (ASPB) is introduced. The algorithm uses the standard pencil beam technique of laterally distributing the central axis broad beam doses according to the Moliere scattering theory extended to slablike vary...

journal_title：Medical physics

authors： Ciangaru G,Polf JC,Bues M,Smith AR

更新日期：2005-12-01 00:00:00

abstract：:Several investigators have approximated the scatter component of digital radiographic images by applying a constant weighting factor to a convolved version of the detected image. The scatter approximation is then subtracted from the detected image. When a constant weighting factor is used, the scatter in areas of low ...

journal_title：Medical physics

authors： Naimuddin S,Hasegawa B,Mistretta CA

更新日期：1987-05-01 00:00:00

abstract：:Accurately assessing the quality of prostate brachytherapy intraoperatively would be valuable for improved clinical outcome by ensuring the delivery of a prescribed tumoricidal radiation dose to the entire prostate gland. One necessary step towards this goal is the robust and rapid localization of implanted seeds. Sev...

journal_title：Medical physics

authors： Tutar IB,Managuli R,Shamdasani V,Cho PS,Pathak SD,Kim Y

更新日期：2003-12-01 00:00:00

abstract：PURPOSE:To assess current education, practices, attitudes, and perceptions pertaining to ethics and professionalism in medical physics. METHODS:A link to a web-based survey was distributed to the American Association of Physicists in Medicine (AAPM) e-mail membership list, with a follow-up e-mail sent two weeks later....

journal_title：Medical physics

authors： Ozturk N,Armato SG 3rd,Giger ML,Serago CF,Ross LF

更新日期：2013-04-01 00:00:00

abstract：PURPOSE:To present a noninvasive technique for directly measuring the CT bow-tie filter attenuation with a linear array x-ray detector. METHODS:A scintillator based x-ray detector of 384 pixels, 307 mm active length, and fast data acquisition (model X-Scan 0.8c4-307, Detection Technology, FI-91100 Ii, Finland) was use...

journal_title：Medical physics

authors： Li X,Shi JQ,Zhang D,Singh S,Padole A,Otrakji A,Kalra MK,Xu XG,Liu B

更新日期：2015-11-01 00:00:00

abstract：PURPOSE:Color images are visualized on medical monitors that are adjusted by a grayscale standard display function (GSDF) or γ2.2. Although the GSDF is visually displayed as a linear graded grayscale, it does not specify how color medical images should be presented. On the other hand, the usual gamma setting for color ...

journal_title：Medical physics

authors： Shibutani T,Onoguchi M,Yoneyama H,Nakajima K,Matsuo S,Bamba Y,Saito S

更新日期：2019-06-01 00:00:00

abstract：:This paper compares the characteristics of three types of commercial p-type electron diodes specially designed for in vivo dosimetry (Scanditronix EDD2, Sun Nuclear QED 111200-0 and PTW T60010E diodes coupled with a Therados DPD510 dosimeter) in electron fields with energies from 4.5 to 21 MeV, and in conditions simil...

journal_title：Medical physics

authors： Marre D,Marinello G

更新日期：2004-01-01 00:00:00

abstract：PURPOSE:In radiotherapy, it is important to predict the response of tumors to irradiation prior to the treatment. This is especially important for hypoxic tumors, which are known to be highly radioresistant. Mathematical modeling based on the dose distribution, biological parameters, and medical images may help to impr...

journal_title：Medical physics

authors： Espinoza I,Peschke P,Karger CP

更新日期：2015-01-01 00:00:00

abstract：:Direct comparisons of the National Institute of Standards and Technology's (NIST) Ritz 20 kV to 100 kV standard free-air ionization chamber and a portable variable-length free-air ionization chamber designed by the University of Wisconsin-Madison Accredited Dosimetry Calibration Laboratory (UW-ADCL) were made on NISTs...

journal_title：Medical physics

authors： Coletti JG,Pearson DW,DeWerd LA,O'Brien CM,Lamperti PJ

更新日期：1997-08-01 00:00:00

abstract：PURPOSE:The previously described 2D standardized vessel-wall-plus-plaque thickness (VWT) maps constructed from 3D ultrasound vessel wall measurements using an arc-length (AL) scaling approach adjusted the geometric variability of carotid arteries and has allowed for the comparisons of VWT distributions in longitudinal ...

journal_title：Medical physics

authors： Chen Y,Chiu B

更新日期：2016-12-01 00:00:00

abstract：:This is an introductory tutorial to the field of microdosimetry. Following a brief historical outline, we review the physics of experimental and theoretical microdosimetry and the application of microdosimetry to radiation biology within the so-called "site" approximation. Modern interpretations of microdosimetry that...

journal_title：Medical physics

authors： Rossi HH,Zaider M

更新日期：1991-11-01 00:00:00

abstract：:Single photon emission computed tomography (SPECT) is an important technology for molecular imaging studies of small animals. In this arena, there is an increasing demand for high performance imaging systems that offer improved spatial resolution and detection efficiency. We have designed a multipinhole small animal i...

journal_title：Medical physics

authors： Funk T,Després P,Barber WC,Shah KS,Hasegawa BH

更新日期：2006-05-01 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：:A test device which can indirectly measure the performance of an automatic exposure control system and which offers the potential to reduce the time and film requirements for such tests has been evaluated. Evaluation results demonstrate that the device can successfully predict image optical density to within +/- 0.10 ...

journal_title：Medical physics

authors： Rossi RP

更新日期：1994-01-01 00:00:00

abstract：PURPOSE:Different approaches have been used in dynamic elastography to assess mechanical properties of biological tissues. Most techniques are based on a simple inversion based on the measurement of the shear wave speed to assess elasticity, whereas some recent strategies use more elaborated analytical or finite elemen...

journal_title：Medical physics

authors： Ouared A,Kazemirad S,Montagnon E,Cloutier G

更新日期：2016-04-01 00:00:00

abstract：PURPOSE:This work is to evaluate the effects of Compton current generation in three small-volume ionization chambers on measured beam characteristics for electron fields. METHODS:Beam scans were performed using Exradin A16, A26, and PTW 31014 microchambers. Scans with varying chamber components shielded were performed...

journal_title：Medical physics

authors： Tanny S,Holmes S,Sperling N,Parsai EI

更新日期：2015-10-01 00:00:00