The use of a realistic VMAT delivery emulator to optimize dynamic machine parameters for improved treatment efficiency.

abstract：:By analyzing the radiobiological model, and the equations derived from the model, it is shown that the main results of the article 'The influence of dose heterogeneity on tumor control probability in fractionated radiation therapy' by Wiklund et al (2011 Phys. Med. Biol. 56 7585-600) are valid only under the condition...

journal_title：Physics in medicine and biology

authors： Grusell E

更新日期：2013-09-21 00:00:00

abstract：:The basic principles of x-ray image formation in radiology have remained essentially unchanged since Röntgen first discovered x-rays over a hundred years ago. The conventional approach relies on x-ray attenuation as the sole source of contrast and draws exclusively on ray or geometrical optics to describe and interpre...

journal_title：Physics in medicine and biology

authors： Bech M,Bunk O,Donath T,Feidenhans'l R,David C,Pfeiffer F

更新日期：2010-09-21 00:00:00

abstract：:4D cone beam computed tomography (4DCBCT) is an emerging image guidance strategy used in radiotherapy where projections acquired during a scan are sorted into respiratory bins based on the respiratory phase or displacement. 4DCBCT reduces the motion blur caused by respiratory motion but increases streaking artefacts d...

journal_title：Physics in medicine and biology

authors： O'Brien RT,Kipritidis J,Shieh CC,Keall PJ

更新日期：2014-10-07 00:00:00

abstract：:Dielectric properties of porcine glandular tissues and gonads (in vivo) and body fluids (in vitro) have been obtained in the frequency range of 50 MHz to 20 GHz. The experimental data were fitted to a two term Cole-Cole expression. The data presented complement the available dielectric properties of tissues in the lit...

journal_title：Physics in medicine and biology

authors： Peyman A,Gabriel C

更新日期：2012-10-07 00:00:00

abstract：:This study presents a new approach to accurately account for the medium-dependent effect in model-based dose calculations for kilovoltage (kV) x-rays. This approach is based on the hypothesis that the correction factors needed to convert dose from model-based dose calculations to absorbed dose-to-medium depend on both...

journal_title：Physics in medicine and biology

authors： Pawlowski JM,Ding GX

更新日期：2011-07-07 00:00:00

abstract：:The dose-calculation accuracy of the tomotherapy Hi-Art II(R) (Tomotherapy, Inc., Madison, WI) treatment planning system (TPS) in the presence of low-density lung media was investigated. In this evaluation, a custom-designed heterogeneous phantom mimicking the mediastinum geometry was used. Gammex LN300 and balsa wood...

journal_title：Physics in medicine and biology

authors： Chaudhari SR,Pechenaya OL,Goddu SM,Mutic S,Rangaraj D,Bradley JD,Low D

更新日期：2009-04-21 00:00:00

abstract：:In response to the recognized fragility of reactor-produced (99)Mo supply, direct production of (99m)Tc via (100)Mo(p,2n)(99m)Tc reaction using medical cyclotrons has been investigated. However, due to the existence of other Molybdenum (Mo) isotopes in the target, in parallel with (99m)Tc, other technetium (Tc) radioa...

journal_title：Physics in medicine and biology

authors： Hou X,Tanguay J,Buckley K,Schaffer P,Bénard F,Ruth TJ,Celler A

更新日期：2016-01-21 00:00:00

abstract：:The degradation of low energy electrons in a methane based, tissue equivalent gas was studied experimentally by ionization chamber experiments and theoretically by Monte Carlo electron transport simulation in the energy range between 25 eV and 5 keV. From measured ionization yields and calculated ionization and energy...

journal_title：Physics in medicine and biology

authors： Waibel E,Grosswendt B

更新日期：1992-05-01 00:00:00

abstract：:The fluence to organ-dose and effective-dose conversion coefficients for neutrons and protons with energies up to 100 GeV was calculated using the PHITS code coupled to male and female adult reference computational phantoms, which are to be released as a common ICRP/ICRU publication. For the calculation, the radiation...

journal_title：Physics in medicine and biology

authors： Sato T,Endo A,Zankl M,Petoussi-Henss N,Niita K

更新日期：2009-04-07 00:00:00

abstract：:Voltage-sensitive dyes are an important tool in visualizing electrical activity in cardiac tissue. Until today, they have mainly been applied in cardiac electrophysiology to subsurface imaging. In the present study, we assess different imaging methods used in optical tomography with respect to their effectiveness in v...

journal_title：Physics in medicine and biology

authors： Bernus O,Wellner M,Mironov SF,Pertsov AM

更新日期：2005-01-21 00:00:00

abstract：:Brain stereotactic radiosurgery (SRS) treatments require multiple quality assurance (QA) procedures to ensure accurate and precise treatment delivery. As single-isocenter multitarget SRS treatments become more popular, the quantification of off-axis accuracy of the linear accelerator is crucial. In this study, a novel...

journal_title：Physics in medicine and biology

authors： Capaldi DPI,Skinner LB,Dubrowski P,Yu AS

更新日期：2020-06-10 00:00:00

abstract：:Sparse phased array ultrasound transducers with millimetre length scale elements have previously been proposed for generating hyperthermia but not for imaging. Numerical simulation with a pseudospectral solver was used to investigate: (a) how the position of the maximum pressure in the focal region changed with elemen...

journal_title：Physics in medicine and biology

authors： Wilson AJ

更新日期：2018-07-16 00:00:00

abstract：:Several applications in nuclear medicine require absolute activity quantification of single photon emission computed tomography images. Obtaining a repeatable calibration factor that converts voxel values to activity units is essential for these applications. Because source preparation and measurement of the source ac...

journal_title：Physics in medicine and biology

authors： Anizan N,Wang H,Zhou XC,Wahl RL,Frey EC

更新日期：2015-02-07 00:00:00

abstract：:Monte Carlo simulation provides a valuable tool in performance assessment and optimization of system design parameters for PET scanners. SimSET is a popular Monte Carlo simulation toolkit that features fast simulation time, as well as variance reduction tools to further enhance computational efficiency. However, SimSE...

journal_title：Physics in medicine and biology

authors： Poon JK,Dahlbom ML,Casey ME,Qi J,Cherry SR,Badawi RD

更新日期：2015-02-07 00:00:00

abstract：:In elastography we have previously developed a tracking and correction method that estimates the axial and lateral strain components along and perpendicular to the compressor/scanning axis following an externally applied compression. However, the resulting motion is a three-dimensional problem. Therefore, in order to ...

journal_title：Physics in medicine and biology

authors： Konofagou EE,Ophir J

更新日期：2000-06-01 00:00:00

abstract：:During image-guided cancer radiation treatment, three-dimensional (3D) tumor volumetric information is important for treatment success. However, it is typically not feasible to image a patient's 3D tumor continuously in real time during treatment due to concern over excessive patient radiation dose. We present a new i...

journal_title：Physics in medicine and biology

authors： Mao S,Wu H,Sandison G,Fang S

更新日期：2017-02-21 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：:Microbeam radiation therapy (MRT) is a pre-clinical, spatially-fractionated treatment modality noted for its ability to achieve a large differential response between normal and tumoral tissues. In the present study, TOPAS Monte Carlo (MC) simulations were used to optimize the design of a compact, affordable multi-slit...

journal_title：Physics in medicine and biology

authors： Esplen NM,Chergui L,Johnstone CD,Bazalova-Carter M

更新日期：2018-08-29 00:00:00

abstract：:Successful radiotherapy treatment depends heavily upon the accuracy of patient geometry captured during treatment simulation using computed tomography (CT) scans. Radiotherapy patients are often scanned under free breathing, and respiratory motion can cause severe artifacts in CT scans, including shortening, elongatio...

journal_title：Physics in medicine and biology

authors： Lewis JH,Jiang SB

更新日期：2009-02-07 00:00:00

abstract：:Recently, there has been an increased interest in imaging different pulmonary disorders using PET techniques. Previous work has shown, for static PET/CT, that air content in the lung influences reconstructed image values and that it is vital to correct for this 'tissue fraction effect' (TFE). In this paper, we extend ...

journal_title：Physics in medicine and biology

authors： Holman BF,Cuplov V,Millner L,Hutton BF,Maher TM,Groves AM,Thielemans K

更新日期：2015-09-21 00:00:00

abstract：:Multi-atlas segmentation (MAS) has been widely used to automate the delineation of organs at risk (OARs) for radiotherapy. Label fusion is a crucial step in MAS to cope with the segmentation variabilities among multiple atlases. However, most existing label fusion methods do not consider the potential dosimetric impac...

journal_title：Physics in medicine and biology

authors： Chang J,Tian Z,Lu W,Gu X,Chen M,Jiang SB

更新日期：2017-05-07 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：:This study presents a theoretical approach to the dosimetry for small and non-equilibrium radiation fields. We applied the newly developed VMCBC algorithm to the dosimetry for megavoltage photon beams using Monte Carlo techniques. The approach assumes that a Monte Carlo simulated beam can be calibrated per incident pa...

journal_title：Physics in medicine and biology

authors： Ding GX,Duggan DM,Coffey CW

更新日期：2008-07-07 00:00:00

abstract：:For medical applications of ultrasound inside the brain, it is necessary to understand the relationship between the apparent density of skull bone and its corresponding speed of sound and attenuation coefficient. Although there have been previous studies exploring this phenomenon, there is still a need to extend the m...

journal_title：Physics in medicine and biology

authors： Pichardo S,Sin VW,Hynynen K

更新日期：2011-01-07 00:00:00

abstract：:Maximum likelihood estimation (MLE) is presented as a statistical tool to evaluate the contribution of measurement error to any measurement series where the same quantity is measured using different independent methods. The technique was tested against artificial data sets; generated for values of underlying variation...

journal_title：Physics in medicine and biology

authors： Sage JP,Mayles WP,Mayles HM,Syndikus I

更新日期：2014-10-21 00:00:00

abstract：:It is a challenging problem to resolve and identify drug (or non-specific fluorophore) distribution throughout the whole body of small animals in vivo. In this article, an algorithm of unmixing multispectral fluorescence tomography (MFT) images based on independent component analysis (ICA) is proposed to solve this pr...

journal_title：Physics in medicine and biology

authors： Pu H,Zhang G,He W,Liu F,Guang H,Zhang Y,Bai J,Luo J

更新日期：2014-09-07 00:00:00

abstract：:Distributions of linear pathlength measurements have been utilized in skeletal dosimetry of internally emitted short-range particles for over 30 years. This work reviews the methods for coupling these distributions to range-energy data. A revised methodology is presented for handling the insertion of the additional do...

journal_title：Physics in medicine and biology

authors： Jokisch DW,Rajon DA,Patton PW,Bolch WE

更新日期：2011-05-07 00:00:00

abstract：:The medical imaging and therapeutic technologies that are based on the use of radiation are reviewed briefly, with special emphasis on the recent developments of synchrotron radiation (SR) methods. New results have been achieved in all of these areas since the last comprehensive reviews were written in this field. Thi...

journal_title：Physics in medicine and biology

authors： Suortti P,Thomlinson W

更新日期：2003-07-07 00:00:00

abstract：:The radiofrequency dielectric behaviour of packed human erythrocytes has been investigated in normal haemoglobins F and AA and also abnormal haemoglobins homozygous SS and heterozygous AS. Dielectric measurements were made in tightly packed blood cells at an average room temperature of 26.5 +/- 0.5 degrees C in the fr...

journal_title：Physics in medicine and biology

authors： Laogun AA,Ajayi NO,Okafor LO,Osamo NO

更新日期：1983-04-01 00:00:00

abstract：:A computerized system for monitoring dose-area product (DAP) has been developed for region of interest (ROI) fluoroscopy in which patient exposure is reduced using an x-ray attenuating filter with an aperture. The system includes an IBM compatible computer which is connected through an IEEE-488 interface to an electro...

journal_title：Physics in medicine and biology

authors： Kezerashvili M,Bednarek DR,Rudin S

更新日期：1997-04-01 00:00:00