Image reconstruction algorithm for a rotating slat collimator.

abstract：:Functional single photon emission computed tomography (SPECT) images of brain activation are based on a comparison of base line and activation images. The correctness of the functional images depends, among other factors, on the accurate spatial registration (alignment) of the base line and activation image data. The ...

journal_title：Medical physics

authors： Sychra JJ,Pavel DG,Chen Y,Jani A

更新日期：1994-12-01 00:00:00

abstract：PURPOSE:By means of Monte Carlo (MC) simulations and indirect measurements, we have evaluated the maximum dose rates achievable with conventional x-ray tubes and related them to FLASH therapy dose rates of >40 Gy/s. METHODS:Monte Carlo models of two 160 kV x-ray tubes, the 3-kW MXR-160/22 and the 6-kW MXR-165, were bu...

journal_title：Medical physics

authors： Bazalova-Carter M,Esplen N

更新日期：2019-12-01 00:00:00

abstract：:The nuclear magnetic resonance phenomenon has given rise to both magnetic resonance imaging, which yields morphologic data, and magnetic resonance spectroscopy (MRS), which yields chemical data. In humans these data are derived principally from the resonances of the hydrogen nucleus in the low molecular weight compoun...

journal_title：Medical physics

authors： Prost RW

更新日期：2008-10-01 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 article presents a new reconstruction method for 3D imaging using a multiple 360 degrees circular orbit cone beam CT system, specifically a way to combine 3D volumes reconstructed with each orbit. The main goal is to improve the noise performance in the combined image while avoiding cone beam artifacts. M...

journal_title：Medical physics

authors： Baek J,Pelc NJ

更新日期：2010-10-01 00:00:00

abstract：PURPOSE:Spirometry exhibits baseline drift and frequent measurement errors so it cannot be used by itself to provide tidal volume-based image sorting or breathing motion modeling. Other breathing surrogates, in this study an abdominal bellows system, are drift free but do not measure tidal volume. Simultaneously using ...

journal_title：Medical physics

authors： Werner R,White B,Handels H,Lu W,Low DA

更新日期：2010-02-01 00:00:00

abstract：PURPOSE:In cardiac ablation therapy, accurate anatomic guidance is necessary to create effective tissue lesions for elimination of left atrial fibrillation. While fluoroscopy, ultrasound, and electroanatomic maps are important guidance tools, they lack information regarding detailed patient anatomy which can be obtaine...

journal_title：Medical physics

authors： Rettmann ME,Holmes DR 3rd,Kwartowitz DM,Gunawan M,Johnson SB,Camp JJ,Cameron BM,Dalegrave C,Kolasa MW,Packer DL,Robb RA

更新日期：2014-02-01 00:00:00

abstract：PURPOSE:Several treatment response metrics, such as RECIST and PERCIST, have been established for assessing individual solid tumors. However, metastatic prostate cancer poses a unique challenge to these metrics because bone lesions are often numerous and non-measureable. This study investigated the impact of using diff...

journal_title：Medical physics

authors： Morrison C,Liu G,Jeraj R

更新日期：2012-06-01 00:00:00

abstract：PURPOSE:To investigate how using different sets of decision criteria impacts the quality of intensity modulated radiation therapy (IMRT) plans obtained by multiobjective optimization. METHODS:A multiobjective optimization evolutionary algorithm (MOEA) was used to produce sets of IMRT plans. The MOEA consisted of two i...

journal_title：Medical physics

authors： Holdsworth C,Stewart RD,Kim M,Liao J,Phillips MH

更新日期：2011-06-01 00:00:00

abstract：PURPOSE:To develop a real-time markerless 3D tumor tracking using kilovoltage (kV) cone-beam CT (CBCT) projection images during volumetric modulated arc therapy (VMAT) treatment of lung tumors. METHODS:The authors have developed a method to identify the position of lung tumors during VMAT treatment, where the current ...

journal_title：Medical physics

authors： Zhuang L,Liang J,Yan D,Zhang T,Marina O,Ionascu D

更新日期：2013-10-01 00:00:00

abstract：PURPOSE:Automated 3D breast ultrasound (ABUS) has gained interest in breast imaging. Especially for screening women with dense breasts, ABUS appears to be beneficial. However, since the amount of data generated is large, the risk of oversight errors is substantial. Computer aided detection (CADe) may be used as a secon...

journal_title：Medical physics

authors： Tan T,Mordang JJ,van Zelst J,Grivegnée A,Gubern-Mérida A,Melendez J,Mann RM,Zhang W,Platel B,Karssemeijer N

更新日期：2015-04-01 00:00:00

abstract：:Radiation sensitive gels have been used as dosimeters for clinical dose verification of different radiation therapy modalities. However, the use of gels is not widespread, because careful techniques are required to achieve the dose precision and accuracy aimed for in clinical dose verification. Here, the introduction ...

journal_title：Medical physics

authors： Crescenti RA,Scheib SG,Schneider U,Gianolini S

更新日期：2007-04-01 00:00:00

abstract：PURPOSE:The x-ray performance evaluation of digital x-ray detectors is based on the calculation of the modulation transfer function (MTF), the noise power spectrum (NPS), and the resultant detective quantum efficiency (DQE). The flat images used for the extraction of the NPS should not contain any fixed pattern noise (...

journal_title：Medical physics

authors： Konstantinidis AC,Olivo A,Speller RD

更新日期：2011-12-01 00:00:00

abstract：:This paper deals with methods of reducing the total time required to acquire the projection data for a set of contiguous computed tomography (CT) images. Normally during the acquisition of a set of slices, the patient is held stationary during data collection and translated to the next axial location during an intersc...

journal_title：Medical physics

authors： Crawford CR,King KF

更新日期：1990-11-01 00:00:00

abstract：:As a potentially important technology for medical x-ray computed tomography (CT), lambda tomography (LT) is to reconstruct a gradient-like image only from local projection data. Based on our recently derived exact fan-beam LT formula, [H. Y. Gu and G. Wang, Int. J. Biomed. Imaging 2006(1), 1-9 (2006)] here we propose ...

journal_title：Medical physics

authors： Yu H,Ye Y,Wang G

更新日期：2006-10-01 00:00:00

abstract：:The use of characteristic-line radiation from rare-earth targets bombarded by high-energy (up to 1 MeV) electron beams has been evaluated as an x-ray source for dual energy K-edge subtraction imaging of the human coronary arteries. Two characteristic-line x-ray sources, one using the split K alpha 1 and K alpha 2 line...

journal_title：Medical physics

authors： Manning HL,Shefer RE,Klinkowstein RE,Mistretta CA

更新日期：1991-09-01 00:00:00

abstract：PURPOSE:Proton radiotherapy for head-and-neck cancer (HNC) aims to improve organ-at-risk (OAR) sparing over photon radiotherapy. However, it may be less robust for setup and range uncertainties. The authors investigated OAR sparing and plan robustness for spot-scanning proton planning techniques and compared these with...

journal_title：Medical physics

authors： Barten DL,Tol JP,Dahele M,Slotman BJ,Verbakel WF

更新日期：2015-11-01 00:00:00

abstract：PURPOSE:We investigated the feasibility of using simpler methods than manual whole-organ volume-of-interest (VOI) definition to estimate the organ activity concentration in single photon emission computed tomography (SPECT) in cases where the activity in the organ can be assumed to be uniformly distributed on the scale...

journal_title：Medical physics

authors： Vicente EM,Lodge MA,Rowe SP,Wahl RL,Frey EC

更新日期：2017-05-01 00:00:00

abstract：:The half-life of two I-125 encapsulated clinical seeds was measured with a Si(Li) semiconductor detector. Two measurements of each seed yielded an average half-life of 59.56 +/- 0.17 days. The results are discussed in terms of the influence of possible I-126 contamination and leakage of I-125 activity through encapsul...

journal_title：Medical physics

authors： Kubo H

更新日期：1983-11-01 00:00:00

abstract：PURPOSE:Statistical modeling of an ultrasound backscattered echo envelope is used for tissue characterization. However, in the presence of complex structures within the analyzed area, estimation of parameters is disturbed and unreliable, e.g., in the case of breast tumor classification. In order to improve the differen...

journal_title：Medical physics

authors： Byra M,Nowicki A,Wróblewska-Piotrzkowska H,Dobruch-Sobczak K

更新日期：2016-10-01 00:00:00

abstract：:The gamma-ray dose component of a d(80) + Be neutron beam was measured with a 6Li-shielded Geiger-Mueller counter in a tissue-equivalent liquid phantom. The proportion of gamma-ray dose to total dose increased from 0.07 near the surface to 0.09 at 25 cm depth. Due to thermal neutron sensitivity, the G-M count rate inc...

journal_title：Medical physics

authors： Harrison GH,Cox CR

更新日期：1979-05-01 00:00:00

abstract：:Interstitial brachytherapy for carcinoma of the prostate is achieved through the use of a configuration of radioactive seeds placed in a manner that delivers a customized, reasonably uniform dose to the target volume. Accurate dose delivery depends on both precise seed placement and reliable seed strength in the impla...

journal_title：Medical physics

authors： Rosenzweig DP,Schell MC,Yu Y

更新日期：2000-01-01 00:00:00

abstract：:The trend toward conformal techniques in stereotactic radiosurgery necessitates an accurate and practical method for verification of irregular three-dimensional dose distributions. This work presents the design and evaluation of a phantom system facilitating the measurement of conformal dose distributions using one or...

journal_title：Medical physics

authors： Robar JL,Clark BG

更新日期：2000-05-01 00:00:00

abstract：:The nucletron Leipzig applicator is designed for (HDR) 192Ir brachy radiotherapy of surface lesions. The dosimetric characteristics of this applicator were investigated using simulation method based on Monte Carlo N-particle (MCNP) code and phantom measurements. The simulation method was validated by comparing calcula...

journal_title：Medical physics

authors： Niu H,Hsi WC,Chu JC,Kirk MC,Kouwenhoven E

更新日期：2004-12-01 00:00:00

abstract：:Respiration can cause tumors in the thorax or abdomen to move by as much as 3 cm; this movement can adversely affect the planning and delivery of radiation treatment. Several techniques have been used to compensate for respiratory motion, but all have shortcomings. Manufacturers of computed tomography (CT) equipment h...

journal_title：Medical physics

authors： Fitzpatrick MJ,Starkschall G,Antolak JA,Fu J,Shukla H,Keall PJ,Klahr P,Mohan R

更新日期：2006-01-01 00:00:00

abstract：PURPOSE:To use Cone Beam CT scans obtained just prior to treatments of head and neck cancer patients to measure the setup error and cumulative dose uncertainty of the cochlea. METHODS:Data from 10 head and neck patients with 10 planning CTs and 52 Cone Beam CTs taken at time of treatment were used in this study. Patie...

journal_title：Medical physics

authors： Yan M,Lovelock D,Hunt M,Mechalakos J,Hu Y,Pham H,Jackson A

更新日期：2013-12-01 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：PURPOSE:Lower radiation tolerance of the whole liver hinders dose escalations of stereotactic body radiation therapy (SBRT) in hepatocellular carcinoma (HCC) treatment. This study was conducted to define the exact doses that result in radiation-induced liver disease (RILD) as well as to determine dose constraints for t...

journal_title：Medical physics

authors： Wu ZF,Zhang JY,Shen XY,Zhou LY,Gao YB,Hu Y,Zeng ZC

更新日期：2016-07-01 00:00:00

abstract：PURPOSE:Cone beam computed tomography (CBCT) suffers from a large amount of scatter, resulting in severe scatter artifacts in the reconstructions. Recently, a new scatter correction approach, called improved primary modulator scatter estimation (iPMSE), was introduced. That approach utilizes a primary modulator that is...

journal_title：Medical physics

authors： Bier B,Berger M,Maier A,Kachelrieß M,Ritschl L,Müller K,Choi JH,Fahrig R

更新日期：2017-09-01 00:00:00

abstract：BACKGROUND AND PURPOSE:The purpose of this study is to develop a deep learning-based approach to simultaneously segment five pelvic organs including prostate, bladder, rectum, left and right femoral heads on cone-beam CT (CBCT), as required elements for prostate adaptive radiotherapy planning. MATERIALS AND METHODS:We...

journal_title：Medical physics

authors： Fu Y,Lei Y,Wang T,Tian S,Patel P,Jani AB,Curran WJ,Liu T,Yang X

更新日期：2020-08-01 00:00:00