In vivo real-time cavitation imaging in moving organs.

abstract：:Ionization quenching in ion beam dosimetry is often related to the fluence- or dose-averaged linear energy transfer (LET). Both quantities are however averaged over a wide LET range and a mixed field of primary and secondary ions. We propose a novel method to correct the quenched luminescence in scintillators exposed ...

journal_title：Physics in medicine and biology

authors： Christensen JB,Almhagen E,Stolarczyk L,Vestergaard A,Bassler N,Andersen CE

更新日期：2019-04-29 00:00:00

abstract：:The bone suppression technique based on advanced image processing can suppress the conspicuity of bones on chest radiographs, creating soft tissue images obtained by the dual-energy subtraction technique. This study was performed to evaluate the usefulness of bone suppression image processing in image-guided radiation...

journal_title：Physics in medicine and biology

authors： Tanaka R,Sanada S,Sakuta K,Kawashima H

更新日期：2015-05-21 00:00:00

abstract：:A method has been developed which, by using the geometric information from treatment sample cases, selects from a given data set an initial treatment plan as a step for treatment plan optimization. The method uses an artificial neural network (ANN) classification technique to select a best matching plan from the 'opti...

journal_title：Physics in medicine and biology

authors： Hosseini-Ashrafi ME,Bagherebadian H,Yahaqi E

更新日期：1999-06-01 00:00:00

abstract：:High-resolution computations of induced fields are used to assess equivalent source levels for human exposure to uniform low-frequency electric and magnetic fields. These results pertain to 60 Hz foot-to-head electric excitation of the body in three positions with respect to a ground plane, and to magnetic excitation ...

journal_title：Physics in medicine and biology

authors： Dawson TW,Caputa K,Stuchly MA

更新日期：1997-12-01 00:00:00

abstract：:The purpose of this study was to develop a method to simulate breathing motion induced interplay effects for volumetric modulated arc therapy (VMAT), to verify the proposed method with measurements, and to use the method to investigate how interplay effects vary with different patient- and machine specific parameters....

journal_title：Physics in medicine and biology

authors： Edvardsson A,Nordström F,Ceberg C,Ceberg S

更新日期：2018-04-19 00:00:00

abstract：:The objective in cancer radiotherapy is to maximize tumor-kill while limiting toxic effects of radiation dose on nearby organs-at-risk (OAR). Given a fixed number of treatment sessions, planners thus face the problem of finding a dosing sequence that achieves this goal. This is called the fractionation problem, and ha...

journal_title：Physics in medicine and biology

authors： Ghate A

更新日期：2020-09-16 00:00:00

abstract：:A motorized electron multileaf collimator (eMLC) was developed as an add-on device to the Varian linac for delivery of advanced electron beam therapy. It has previously been shown that electron beams collimated by an eMLC have very similar penumbra to those collimated by applicators and cutouts. Thus, manufacturing pa...

journal_title：Physics in medicine and biology

authors： Eldib A,Jin L,Li J,Ma CM

更新日期：2013-08-21 00:00:00

abstract：:Respiratory research with mice using micro-computed tomography (micro-CT) has been predominantly hindered by the limited resolution and signal-to-noise ratio (SNR) as a result of respiratory motion artefacts. In this study, we develop a novel technique for capturing the lung microstructure in vivo using micro-CT, thro...

journal_title：Physics in medicine and biology

authors： Namati E,Chon D,Thiesse J,Hoffman EA,de Ryk J,Ross A,McLennan G

更新日期：2006-12-07 00:00:00

abstract：:Fully three-dimensional positron emission tomography is considered and a reconstruction algorithm derived. The reconstruction problem is formulated mathematically as a three-dimensional convolution integral of a point spread function with an unknown positron activity distribution and is solved by Fourier transform met...

journal_title：Physics in medicine and biology

authors： Colsher JG

更新日期：1980-01-01 00:00:00

abstract：:Although field area and object thickness are important parameters in comparisons of techniques for optimal reduction of scattered radiation to the image, they are in practice seldom varied. For this reason, we suggest that contrast degradation (CDF) and contrast improvement (CIF) factors be more frequently used and ap...

journal_title：Physics in medicine and biology

authors： Carlsson GA,Carlsson CA,Nielsen B,Persliden J

更新日期：1986-07-01 00:00:00

abstract：:Amorphous silicon (aSi:H) flat panel detectors are prevalent in radiotherapy for megavoltage imaging tasks. Any clinical and dosimetrical application requires a well-defined dose response of the system to achieve meaningful results. Due to radiation damages, panels deteriorate and the linearity of pixel response to do...

journal_title：Physics in medicine and biology

authors： Huber S,Mooslechner M,Mitterlechner B,Weichenberger H,Serpa M,Sedlmayer F,Deutschmann H

更新日期：2013-09-21 00:00:00

abstract：:In vivo neutron activation analysis was used to measure total body sodium and chlorine in 18 male and 18 female normal adults. Corrections for body size were developed. Normalisation factors were derived which enable the prediction of the normal levels of sodium and chlorine in a subject. The coefficient of variation ...

journal_title：Physics in medicine and biology

authors： Kennedy NS,Eastell R,Smith MA,Tothill P

更新日期：1983-03-01 00:00:00

abstract：:The treatment delivery time of intensity-modulated radiation therapy (IMRT) with a multileaf collimator (MLC) is generally longer than that of conventional radiotherapy. In theory, removing the flattening filter from the treatment head may reduce the beam-on time by enhancing the output dose rate, and then reduce the ...

journal_title：Physics in medicine and biology

authors： Fu W,Dai J,Hu Y,Han D,Song Y

更新日期：2004-04-21 00:00:00

abstract：:Intra-fractional motion is a concern during prostate radiation therapy, as it may cause deviations between planned and delivered radiation doses. Because accurate motion information during treatment delivery is critical to address dose deviation, we developed the projection marker matching method (PM3), a novel method...

journal_title：Physics in medicine and biology

authors： Chi Y,Rezaeian NH,Shen C,Zhou Y,Lu W,Yang M,Hannan R,Jia X

更新日期：2017-07-07 00:00:00

abstract：:Input functions required for positron emission tomography (PET) tracer kinetic modeling are often obtained from arterial blood. In some situations, using short-lived radiotracers, e.g. [(15)O]water, rapid sample handling is required. A method used at several facilities is to pump blood through a detector system at a c...

journal_title：Physics in medicine and biology

authors： Laymon CM,Sashin D,Carney JP,Ruszkiewicz J,Altenburger D,Becker CR,Lopresti BJ,Mason NS,Mountz JM,Price JC,Schavey R,Mathis CA

更新日期：2008-01-21 00:00:00

abstract：:The absolute dose rate around beta sources for intravascular brachytherapy was measured with thin thermoluminescent (TL) dosimeters and radiochromic film. The calibration of these dosimeters was performed at the dose maximum in a 6 MeV electron beam of a linear accelerator. Compared to the values given by the manufact...

journal_title：Physics in medicine and biology

authors： Piessens M,Reynaert N

更新日期：2000-08-01 00:00:00

abstract：:A bright flash of light is emitted by the plasma formed at the focus of an ophthalmic Nd: YAG laser. The purpose of this investigation is to determine whether the plasma flash constitutes a hazard to the operator. The intensity of the flash at the slit lamp eyepiece was measured and the experimentally derived value wa...

journal_title：Physics in medicine and biology

authors： Moseley H,Allan D

更新日期：1987-09-01 00:00:00

abstract：:Artifacts caused by patient breathing and movement during PET data acquisition affect image quality. Respiratory gating is commonly used to gate the list-mode PET data into multiple bins over a respiratory cycle. Non-rigid registration of respiratory-gated PET images can reduce motion artifacts and preserve count stat...

journal_title：Physics in medicine and biology

authors： Li T,Zhang M,Qi W,Asma E,Qi J

更新日期：2020-07-30 00:00:00

abstract：:The standard mammogram form (SMF) representation of an x-ray mammogram is a standardized, quantitative representation of the breast from which the volume of non-fat tissue and breast density can be easily estimated, both of which are of significant interest in determining breast cancer risk. Previous theoretical analy...

journal_title：Physics in medicine and biology

authors： Highnam R,Pan X,Warren R,Jeffreys M,Davey Smith G,Brady M

更新日期：2006-06-07 00:00:00

abstract：:Stopping power data for protons in tissue-equivalent gas (64.4% CH4 + 32.4% CO2 + 3.2% N2, partial pressures) were derived from experimentally determined ranges and from differential ionisation distributions using the differential energy required per ion pair formed to convert ionisation to energy loss. The proton ene...

journal_title：Physics in medicine and biology

authors： Waibel E,Willems G

更新日期：1987-03-01 00:00:00

abstract：:Dynamic radiation therapy techniques require that the treatment head setup varies in time and space during dose delivery. Examples are leaf motion in intensity modulated x-ray therapy, modulator wheel rotation in conventional proton therapy and variable magnet settings in proton beam scanning. Consequently, for Monte ...

journal_title：Physics in medicine and biology

authors： Paganetti H

更新日期：2004-03-21 00:00:00

abstract：:To evaluate the effect of approximations in clinical analytical calculations performed by a treatment planning system (TPS) on dosimetric indices in intensity modulated proton therapy. TPS calculated dose distributions were compared with dose distributions as estimated by Monte Carlo (MC) simulations, calculated with ...

journal_title：Physics in medicine and biology

authors： Yepes P,Adair A,Grosshans D,Mirkovic D,Poenisch F,Titt U,Wang Q,Mohan R

更新日期：2018-02-09 00:00:00

abstract：:Measurements of lung nodule volume with multi-detector computed tomography (MDCT) have been shown to be more accurate and precise compared to conventional lower dimensional measurements. Quantifying the size of lesions is potentially more difficult when the object-to-background contrast is low as with lesions in the l...

journal_title：Physics in medicine and biology

authors： Li Q,Gavrielides MA,Zeng R,Myers KJ,Sahiner B,Petrick N

更新日期：2015-01-21 00:00:00

abstract：:In this study, two computational phantoms of the newborn patient were used to assess individual organ doses and effective doses delivered during head, chest, abdomen, pelvis, and torso examinations using the Siemens SOMATOM Sensation 16 helical multi-slice computed tomography (MSCT) scanner. The stylized phantom used ...

journal_title：Physics in medicine and biology

authors： Staton RJ,Lee C,Lee C,Williams MD,Hintenlang DE,Arreola MM,Williams JL,Bolch WE

更新日期：2006-10-21 00:00:00

abstract：:A detailed Monte Carlo model of a proton therapy treatment head was commissioned to simulate the delivery of small field proton treatments. Small fields are challenging in the planning and quality assurance process because of aperture scattering and dosimetric disequilibrium. Four patients with small fields used in al...

journal_title：Physics in medicine and biology

authors： Bednarz B,Daartz J,Paganetti H

更新日期：2010-12-21 00:00:00

abstract：:An X-ray technique has been developed to enable reproducible and quantitative data to be obtained from radiographs taken by a diagnostic X-ray machine. Careful attention has been paid to the alignment of the specimen and the diagnostic tube and to operating conditions. The choice of X-ray spectrum is described togethe...

journal_title：Physics in medicine and biology

authors： King SD

更新日期：1977-07-01 00:00:00

abstract：:Monte Carlo simulations were used to investigate large-angle x-ray scatter at design energy of 25 keV during small field of view (9.6 cm × 5 cm) differential phase contrast imaging of the breast using Talbot-Lau interferometry. Homogenous, adipose and fibroglandular breasts of uniform thickness ranging from 2 to 8 cm ...

journal_title：Physics in medicine and biology

authors： Vedantham S,Shi L,Karellas A

更新日期：2014-11-07 00:00:00

abstract：:Recent research has suggested that endothelialization of vascular stents is crucial to reducing the risk of late stent thrombosis. With a resolution of approximately 10 microm, optical coherence tomography (OCT) may be an appropriate imaging modality for visualizing the vascular response to a stent and measuring the p...

journal_title：Physics in medicine and biology

authors： Bonnema GT,Cardinal KO,Williams SK,Barton JK

更新日期：2008-06-21 00:00:00

abstract：:A Monte Carlo computer program has been developed for the computation of integral radiation dose to the breast in xeromammography. The results are given in terms of the integral dose per unit area of the breast per unit incident exposure. The calculations have been made for monoenergetic incident photons and the resul...

journal_title：Physics in medicine and biology

authors： Dance DR

更新日期：1980-01-01 00:00:00

abstract：:Calibration methods are investigated for the determination of bone density by the Compton scattering method. The scattered radiation from materials of different densities and dimensions is measured for this purpose. A function for the dependence of the intensity on these parameters is derived and compared with the exp...

journal_title：Physics in medicine and biology

authors： Leichter I,Weinreb A,Hazan G

更新日期：1980-07-01 00:00:00