Iterative metal artifact reduction for x-ray computed tomography using unmatched projector/backprojector pairs.

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: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：:The ability of Leksell GammaPlan to perform stereotactic space localizations with image sets where there is misalignment of the patient's head (stereotactic frame and fiducial apparatus) relative to the computed tomography (CT) scanner coordinate system was studied. Misalignment is sometimes necessary for patient comf...

journal_title：Medical physics

authors： Cernica G,Wang Z,Malhotra H,de Boer S,Podgorsak MB

更新日期：2006-04-01 00:00:00

abstract：PURPOSE:To establish accurate experimental dosimetry techniques for reference dose measurements in nonstandard composite fields. METHODS:A cylindrical PMMA phantom filled with water was constructed, at the center of which reference absorbed dose to water for a head and neck IMRT delivery was measured. Based on the pro...

journal_title：Medical physics

authors： Chung E,Bouchard H,Seuntjens J

更新日期：2010-06-01 00:00:00

abstract：PURPOSE:Radiosensitizer enhanced radiotherapy provides the possibility of improved treatment outcomes by preferentially increasing the effectiveness of radiation within the tumor. Proton therapy offers improved sparing of tissue distal of the tumor along the beam path and reduced integral dose compared to conventional ...

journal_title：Medical physics

authors： Peukert D,Kempson I,Douglass M,Bezak E

更新日期：2020-02-01 00:00:00

abstract：:In this report we describe an improvement upon the design by Stanton and Lightfoot for a simple photographic null method to determine the kVp of a diagnostic region x-ray source. The new version has two primary advantages over the Ardran and Crooks design in that it is both simpler and less expensive to produce. ...

journal_title：Medical physics

authors： Netto TG,Cameron JR

更新日期：1985-03-01 00:00:00

abstract：:An important aspect of the intensity modulated radiotherapy (IMRT) process is that of optimizing the beam intensity profiles. Most such methods use a comparison between the defined dose distribution (including prescription dose and dose limits for critical structures) and the current distribution. The comparison may i...

journal_title：Medical physics

authors： Jones L,Hoban P

更新日期：2002-01-01 00:00:00

abstract：:An automated data-acquisition and analysis system has been developed for dosimetry measurements on the pion therapy beam at the Clinton P. Anderson Meson Physics Facility Biomedical Channel in Los Alamos using a PDP-11/45 computer and CAMAC interface. Initialization, test, and monitor programs allow the user to set th...

journal_title：Medical physics

authors： Rosen I,Smith A,Lane R,Kelsey C,Lake D,Hogstrom K,Somers J,Helland J,Kittell R,Amols H,Bradbury J,Richman C

更新日期：1978-03-01 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：:We proposed to use the prostate dose-volume factor (PDVF), derived from the dose-volume dataset of planning target volume (PTV) in prostate radiotherapy to evaluate treatment plans of prostate volumetric modulated arc therapy (VMAT) and intensity modulated radiotherapy (IMRT). To demonstrate plan evaluation using PDVF...

journal_title：Medical physics

authors： Chow J,Jiang R,Markel D

更新日期：2012-07-01 00:00:00

abstract：:The NSD equation, D = 1850 x T0.11 x N0.24, is a celebrated transmogrification of Cohen's two well-known collations of data on response to clinical irradiations (3 degrees erythema and 0.90 ablation of skin cancer) in which the relation of D and T is fixed by the data selected by Cohen and the additional constraint th...

journal_title：Medical physics

authors： Herbert DE Jr

更新日期：1981-11-01 00:00:00

abstract：PURPOSE:Linac-magnetic resonance (MR) systems have been proposed in order to achieve realtime image guided radiotherapy. The design of a new linac-MR system with the in-line 6 MV linac generating x-rays along the symmetry axis of an open MR imager is outlined. This new design allows for a greater MR field strength to a...

journal_title：Medical physics

authors： St Aubin J,Santos DM,Steciw S,Fallone BG

更新日期：2010-09-01 00:00:00

abstract：PURPOSE:The purpose of this work was to generate uncompressed heterogeneous breast phantom models using size-dependent fibroglandular distributions derived from a large cohort of breast CT (bCT) datasets, and to compare differences in normalized glandular dose coefficients for bCT "DgNCT " when the realistic heterogene...

journal_title：Medical physics

authors： Hernandez AM,Becker AE,Boone JM

更新日期：2019-03-01 00:00:00

abstract：PURPOSE:Two types of tumor hypoxia most likely exist in human cancers: Chronic hypoxia due to the paucity of blood capillaries and acute hypoxia due to temporary shutdoWn of microvasculatures or fluctuation in the red cell flux. In a recent hypoxia imaging study using 18F-FMISO PET, the authors observed variation in tr...

journal_title：Medical physics

authors： Wang K,Yorke E,Nehmeh SA,Humm JL,Ling CC

更新日期：2009-10-01 00:00:00

abstract：PURPOSE:To compare how the inclusion of the uncertainties in dose and optical density affects the results of the calibration of Gafchromic(®) EBT3 radiochromic films. METHODS:Five methods of least square minimization were compared for calibration of radiochromic films. These differed in the way in which the uncertaint...

journal_title：Medical physics

authors： Garcia LI,Azorin JF

更新日期：2013-07-01 00:00:00

abstract：:Weighting of given doses from parallel opposed fields is a widespread practice in radiation therapy of cancer in the tonsillar region. In order to determine when weighting is useful, dose distributions on the central axis were calculated for various energies (60Co, 4-, 8-, 15-, and MVp photons), weighting factors, and...

journal_title：Medical physics

authors： Wollin M,Gilbert HA,Kagan AR

更新日期：1976-03-01 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 investigate a novel locally adaptive projection space denoising algorithm for low-dose CT data. METHODS:The denoising algorithm is based on bilateral filtering, which smooths values using a weighted average in a local neighborhood, with weights determined according to both spatial proximity and intensity si...

journal_title：Medical physics

authors： Manduca A,Yu L,Trzasko JD,Khaylova N,Kofler JM,McCollough CM,Fletcher JG

更新日期：2009-11-01 00:00:00

abstract：:We have reported in our previous studies on the methodology, and feasibility of 4D-PET (Gated PET) acquisition, to reduce respiratory motion artifact in PET imaging of the thorax. In this study, we expand our investigation to address the problem of respiration motion in PET/CT imaging. The respiratory motion of four l...

journal_title：Medical physics

authors： Nehmeh SA,Erdi YE,Pan T,Pevsner A,Rosenzweig KE,Yorke E,Mageras GS,Schoder H,Vernon P,Squire O,Mostafavi H,Larson SM,Humm JL

更新日期：2004-12-01 00:00:00

abstract：PURPOSE:Plastic scintillation detectors are used for dosimetry in small radiation fields with high dose gradients, e.g., provided by β-emitting sources like 106 Ru/106 Rh eye plaques. A drawback is a background signal caused by Cerenkov radiation generated by electrons passing the optical fibers (light guides) of this ...

journal_title：Medical physics

authors： Eichmann M,Thomann B

更新日期：2017-09-01 00:00:00

abstract：PURPOSE:The most common metric for comparing measured to calculated dose, such as for pretreatment quality assurance of intensity-modulated photon fields, is a pass rate (%) generated using percent difference (%Diff), distance-to-agreement (DTA), or some combination of the two (e.g., gamma evaluation). For many dosimet...

journal_title：Medical physics

authors： Bailey DW,Nelms BE,Attwood K,Kumaraswamy L,Podgorsak MB

更新日期：2011-11-01 00:00:00

abstract：PURPOSE:There is an increasing interest in calculating linear energy transfer (LET) distributions for proton therapy treatments in order to assess the influence of this quantity in biological terms. Microdosimetric Monte Carlo (MC) simulations are useful tools to calculate dose-averaged LET, as this has been broadly pr...

journal_title：Medical physics

authors： Bertolet A,Baratto-Roldán A,Barbieri S,Baiocco G,Carabe A,Cortés-Giraldo MA

更新日期：2019-09-01 00:00:00

abstract：:With the recent clinical implementation of real-time MRI-guided x-ray beam therapy (MRXT), attention is turning to the concept of combining real-time MRI guidance with proton beam therapy; MRI-guided proton beam therapy (MRPT). MRI guidance for proton beam therapy is expected to offer a compelling improvement to the c...

journal_title：Medical physics

authors： Oborn BM,Dowdell S,Metcalfe PE,Crozier S,Mohan R,Keall PJ

更新日期：2017-08-01 00:00:00

abstract：PURPOSE:To present EBT2 film verification of treatment planning with the eXtend System, a relocatable frame system for multiple-fraction or serial multiple-session radiosurgery. METHODS:A human head shaped phantom simulated the verification process for fractionated Gamma Knife (GK) treatment. Phantom preparation for e...

journal_title：Medical physics

authors： Gopishankar N,Bisht RK

更新日期：2012-06-01 00:00:00

abstract：PURPOSE:To build a statistical model to quantitatively correlate the anatomic features of structures and the corresponding dose-volume histogram (DVH) of head and neck (HN) Tomotherapy (Tomo) plans. To study if the model built upon one intensity modulated radiation therapy (IMRT) technique (such as conventional Linac) ...

journal_title：Medical physics

authors： Lian J,Yuan L,Ge Y,Chera BS,Yoo DP,Chang S,Yin F,Wu QJ

更新日期：2013-12-01 00:00:00

abstract：:The physical characteristics of a clinical charge coupled device (CCD)-based imager (Senovision, GE Medical Systems, Milwaukee, WI) for small-field digital mammography have been investigated. The imager employs a MinR 2000 (Eastman Kodak Company, Rochester, NY) scintillator coupled by a 1:1 optical fiber to a front-il...

journal_title：Medical physics

authors： Vedantham S,Karellas A,Suryanarayanan S,Levis I,Sayag M,Kleehammer R,Heidsieck R,D'Orsi CJ

更新日期：2000-08-01 00:00:00

abstract：:Calcium concentration may be a useful feature for distinguishing benign from malignant lung nodules in computer-aided diagnosis. The calcium concentration can be estimated from the measured CT number of the nodule and a CT number vs calcium concentration calibration line that is derived from CT scans of two or more ca...

journal_title：Medical physics

authors： Goodsitt MM,Chan HP,Way TW,Schipper MJ,Larson SC,Christodoulou EG

更新日期：2009-07-01 00:00:00

abstract：PURPOSE:Optoacoustic imaging enables mapping the optical absorption of biological tissue using optical excitation and acoustic detection. Although most image-reconstruction algorithms are based on the assumption of a detector with an isotropic sensitivity, the geometry of the detector often leads to a response with spa...

journal_title：Medical physics

authors： Rosenthal A,Ntziachristos V,Razansky D

更新日期：2011-07-01 00:00:00

abstract：PURPOSE:An optimized air ventilation system design for a treatment room in Heavy-ion Medical Facility is an important issue in the aspects of nuclear safety because the activated air produced in a treatment room can directly affect the medical staff and the general public in the radiation-free area. METHODS:Optimized ...

journal_title：Medical physics

authors： Kum O

更新日期：2018-06-01 00:00:00

abstract：:Single-photon emission-computed tomography (SPECT) imaging of deep brain structures is compromised by loss of photons due to attenuation. We have previously shown that a centrally peaked collimator sensitivity function can compensate for this phenomenon, increasing sensitivity over most of the brain. For dual-head ins...

journal_title：Medical physics

authors： Park MA,Moore SC,Kijewski MF

更新日期：2005-07-01 00:00:00