The application of sparse arrays in high frequency transcranial focused ultrasound therapy: a simulation study.

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：:A quality assurance protocol has been developed to assess the relative accuracy of computerized monitor unit calculations. Results from this testing reveal that errors (defined as the difference between the computer results and those obtained using a standard formula with manual calculation) in monitor unit calculator...

journal_title：Medical physics

authors： Dahl RA,McCullough EC,Mellenberg DE

更新日期：1990-01-01 00:00:00

abstract：PURPOSE:To evaluate two deformable image registration (DIR) algorithms for the purpose of contour mapping to support image guided adaptive radiotherapy (IGART) with 4D cone beam CT (4DCBCT). METHODS:Eleven locally advanced non-small cell lung cancer (NSCLC) patients underwent one planning 4D fan- beam CT (4DFBCT) and ...

journal_title：Medical physics

authors： Balik S,Hugo G,Weiss E,Jan N,Roman N,Sleeman W,Fatyga M,Christensen G,Murphy M,Lu J,Keall P,Williamson J

更新日期：2012-06-01 00:00:00

abstract：PURPOSE:Dynamic myocardial perfusion computed tomography (DM-PCT) imaging offers benefits over quantitative assessment of myocardial blood flow (MBF) for diagnosis and risk stratification of coronary artery disease. However, one major drawback of DM-PCT imaging is that a high radiation level is imparted by repeated sca...

journal_title：Medical physics

authors： Bian Z,Zeng D,Zhang Z,Gong C,Tian X,Yan G,Huang J,Guo H,Chen B,Zhang J,Feng Q,Chen W,Ma J

更新日期：2017-09-01 00:00:00

abstract：INTRODUCTION:Ultrasound (US) guidance of the prostate has long been conducted using a transabdominal (TA) approach. More recently, a transperineal (TP) approach has been made available for image guidance. Our aim was to determine if both methods produced similar alignments within the same patients. MATERIALS AND METHO...

journal_title：Medical physics

authors： Szegedi M,Boehm C,Paxton A,Rassiah-Szegedi P,Sarkar V,Zhao H,Su F,Kokeny KE,Lloyd S,Tward J,Salter BJ

更新日期：2020-12-01 00:00:00

abstract：PURPOSE:The purpose of this study was to assess, using an anthropomorphic digital phantom, the accuracy of algorithms in registering precontrast and contrast-enhanced computed tomography (CT) chest images for generation of iodine maps of the pulmonary parenchyma via temporal subtraction. MATERIALS AND METHODS:The XCAT...

journal_title：Medical physics

authors： Grob D,Oostveen L,Rühaak J,Heldmann S,Mohr B,Michielsen K,Dorn S,Prokop M,Kachelrieβ M,Brink M,Sechopoulos I

更新日期：2019-05-01 00:00:00

abstract：PURPOSE:Respiratory motion in the chest region during single photon emission computed tomography (SPECT) is a major degrading factor that reduces the accuracy of image quantification. This effect is more notable when the tumor is very small, or the spatial resolution of the imaging system is less than the respiratory m...

journal_title：Medical physics

authors： Naseri M,Rajabi H,Wang J,Abbasi M,Kalantari F

更新日期：2019-11-01 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：PURPOSE:Dedicated breast PET/CT is expected to have utility in local staging, surgical planning, monitoring of therapy response, and detection of residual disease for breast cancer. Quantitative metrics will be integral to several such applications. The authors present a validation of fully 3D data correction schemes f...

journal_title：Medical physics

authors： Bowen SL,Ferrero A,Badawi RD

更新日期：2012-05-01 00:00:00

abstract：PURPOSE:To overcome the problem of organ motion in intensity-modulated radiation therapy (IMRT), gated IMRT is often used for the treatment of lung cancer. In this study, the authors investigated the accuracy of the delivered monitor units (MUs) from each segment during gated IMRT using a two-dimensional detector array...

journal_title：Medical physics

authors： Cheong KH,Kang SK,Lee M,Kim SS,Park S,Hwang TJ,Kim KJ,Oh DH,Bae H,Suh TS

更新日期：2010-03-01 00:00:00

abstract：:A new factor for shifting isodoes curves for oblique Co-60 photon beams has been deduced. Like the two other known factors, this shift factor depends on the source-to-surface distance (SSD), the depth dose (D) and the derivative of D with depth. A comparison of corrected dose distributions has been made by using the t...

journal_title：Medical physics

authors： Iwasaki A,Ishito T

更新日期：1980-05-01 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：:We are developing computerized methods for characterizing the bone texture pattern from digitized skeletal radiographs. For this method to be useful clinically, it must be able to distinguish between weak and strong bone under the range of exposure conditions potentially encountered in the clinical setting. In this st...

journal_title：Medical physics

authors： Chinander MR,Giger ML,Martell JM,Favus MJ

更新日期：2000-01-01 00:00:00

abstract：:Available deformable registration methods are often inaccurate over large organ variation encountered, for example, in the rectum and bladder. The authors developed a novel approach to accurately and effectively register large deformations in the prostate region for adaptive radiation therapy. A software tool combinin...

journal_title：Medical physics

authors： Godley A,Ahunbay E,Peng C,Li XA

更新日期：2009-04-01 00:00:00

abstract：:Intensity modulated radiation therapy (IMRT) with a dynamic multileaf collimator (DMLC) requires synchronization of DMLC leaf motion with dose delivery. A delay in DMLC communication is known to cause leaf lag and lead to dosimetric errors. The errors may be exacerbated by gated operation. The purpose of this study wa...

journal_title：Medical physics

authors： Duan J,Shen S,Fiveash JB,Brezovich IA,Popple RA,Pareek PN

更新日期：2003-08-01 00:00:00

abstract：PURPOSE:To determine the accuracy of VMAT treatment planning and delivery for patients undergoing radiotherapy in the head and neck. METHOD AND MATERIALS:A dosimetric study of a typical head and neck treatment plan has been carried out using Chamber, film and TLD's placed inside an anthropomorphic phantom. Lateral and...

journal_title：Medical physics

authors： Aldaais E,Tedeschi D,Gebreamlak W,Shieder T,Alkhatib H

更新日期：2012-06-01 00:00:00

abstract：PURPOSE:Accurate segmentation of lung and infection in COVID-19 computed tomography (CT) scans plays an important role in the quantitative management of patients. Most of the existing studies are based on large and private annotated datasets that are impractical to obtain from a single institution, especially when radi...

journal_title：Medical physics

authors： Ma J,Wang Y,An X,Ge C,Yu Z,Chen J,Zhu Q,Dong G,He J,He Z,Cao T,Zhu Y,Nie Z,Yang X

更新日期：2020-12-23 00:00:00

abstract：:An important aspect of heavy charged particle radiotherapy is its ability to localize dose to the target volume. Current techniques generally employ beam delivery schemes which use range modulated beams in which the Bragg peak is spread out over a range of depths. The range modulation is constant over the entire beam ...

journal_title：Medical physics

authors： Goitein M,Chen GT

更新日期：1983-11-01 00:00:00

abstract：:A formalism for an independent dose verification of the Gamma Knife treatment planning is developed. It is based on the approximation that isodose distribution for a single shot is in the shape of an ellipsoid in three-dimensional space. The dose profiles for a phantom along each of the three major axes are fitted to ...

journal_title：Medical physics

authors： Phaisangittisakul N,Ma L

更新日期：2002-09-01 00:00:00

abstract：PURPOSE:Hybrid radiotherapy-MRI devices promise real time tracking of moving tumors to focus the radiation portals to the tumor during irradiation. This approach will benefit from the increased temporal resolution of MRI's data acquisition and reconstruction. In this work, the authors propose a novel spatial-temporal c...

journal_title：Medical physics

authors： Yip E,Yun J,Wachowicz K,Heikal AA,Gabos Z,Rathee S,Fallone BG

更新日期：2014-08-01 00:00:00

abstract：:As different types of radionuclides (e.g., 131Cs source) are introduced for clinical use in brachytherapy, the question is raised regarding whether a relatively simple method exists for the derivation of values of the half value layer (HVL) or the tenth value layer (TVL). For the radionuclide that has been clinically ...

journal_title：Medical physics

authors： Yue NJ

更新日期：2008-06-01 00:00:00

abstract：:Ultrasound-induced blood stasis has been observed for more than 30 years. Most of the literature has been focused on the health risks associated with this phenomenon and methods employed to prevent stasis from occurring during ultrasound imaging. To date, experimental observations have been either in vitro or invasive...

journal_title：Medical physics

authors： Winey BA,Misic V,Liao L,Parker K,Fenton BM,Yu Y

更新日期：2006-06-01 00:00:00

abstract：PURPOSE:Intensity-Modulated Radiation Therapy (IMRT), including its variations (including IMRT, Volumetric Arc Therapy (VMAT), and Tomotherapy), is a widely used and critically important technology for cancer treatment. It is a knowledge-intensive technology due not only to its own technical complexity, but also to the...

journal_title：Medical physics

authors： Ge Y,Wu QJ

更新日期：2019-06-01 00:00:00

abstract：PURPOSE:The treatment of moving targets with scanned proton beams is challenging. For motion mitigation, an Active Breathing Coordinator (ABC) can be used to assist breath-holding. The delivery of pencil beam scanning fields often exceeds feasible breath-hold durations, requiring high breath-hold reproducibility. We ev...

journal_title：Medical physics

authors： den Otter LA,Kaza E,Kierkels RGJ,Meijers A,Ubbels FJF,Leach MO,Collins DJ,Langendijk JA,Knopf AC

更新日期：2018-12-01 00:00:00

abstract：PURPOSE:As radiation therapy evolves toward more adaptive techniques, image guidance plays an increasingly important role, not only in patient setup but also in monitoring the delivered dose and adapting the treatment to patient changes. This study aimed to validate a method for evaluation of delivered intensity modula...

journal_title：Medical physics

authors： Moteabbed M,Sharp GC,Wang Y,Trofimov A,Efstathiou JA,Lu HM

更新日期：2015-01-01 00:00:00

abstract：PURPOSE:Flattening filter free (FFF) beams generated by medical linear accelerators have recently started to be used in radiotherapy clinical practice. Such beams present fundamental differences with respect to the standard filter flattened (FF) beams, making the generally used dosimetric parameters and definitions not...

journal_title：Medical physics

authors： Fogliata A,Garcia R,Knoos T,Nicolini G,Clivio A,Vanetti E,Khamphan C,Cozzi L

更新日期：2012-10-01 00:00:00

abstract：:An automated technique for the alignment of right and left breast images has been developed for use in the computerized analysis of bilateral breast images. In this technique, the breast region is first identified in each digital mammogram by use of histogram analysis and morphological filtering operations. The anteri...

journal_title：Medical physics

authors： Yin FF,Giger ML,Doi K,Vyborny CJ,Schmidt RA

更新日期：1994-03-01 00:00:00

abstract：:The purposes of this research are to investigate the effectiveness of our novel image features for segmentation of anatomic regions such as the lungs and the mediastinum in chest radiographs and to develop an automatic computerized method for image processing. A total of 85 screening chest radiographs from Johns Hopki...

journal_title：Medical physics

authors： Tsujii O,Freedman MT,Mun SK

更新日期：1998-06-01 00:00:00

abstract：PURPOSE:It is very important for calculation of clinical indices and diagnosis to detect thyroid nodules from ultrasound images. However, this task is a challenge mainly due to heterogeneous thyroid nodules with distinct components are similar to background in ultrasound images. In this study, we employ cascade deep co...

journal_title：Medical physics

authors： Ma J,Wu F,Jiang T,Zhu J,Kong D

更新日期：2017-05-01 00:00:00

abstract：:In this paper, we present a unified framework to reconstruct images for both fan beam and cone beam projections. The important feature of our theoretical framework is that it does not depend on the classical concept of the Radon transform at all. This property allows us to directly generalize the ideas and techniques ...

journal_title：Medical physics

authors： Chen GH

更新日期：2003-06-01 00:00:00