PET monitoring of cancer therapy with 3He and 12C beams: a study with the GEANT4 toolkit.

abstract：:We present a novel linear programming (LP) based approach for efficiently solving the intensity modulated radiation therapy (IMRT) fluence-map optimization (FMO) problem to global optimality. Our model overcomes the apparent limitations of a linear-programming approach by approximating any convex objective function by...

journal_title：Physics in medicine and biology

authors： Romeijn HE,Ahuja RK,Dempsey JF,Kumar A,Li JG

更新日期：2003-11-07 00:00:00

abstract：:Uncemented prosthetic joint implants used in orthopaedic surgery are usually coated with a porous surface to encourage bone ingrowth. Better contact between the endosteal bone and the porous surface improves ingrowth, and such contact may be increased if the joint further subsides into position in the first weeks foll...

journal_title：Physics in medicine and biology

authors： Berry E,Langkamer VG,Jackson PC,Snow M,Goddard PR,Wells PN

更新日期：1993-02-01 00:00:00

abstract：:Gold nanoparticle (GNP) radio-enhancement is a promising technique to increase the dose deposition in a tumor while sparing neighboring healthy tissue. Previous experimental studies showed effects on cell survival and tumor control for keV x-rays but surprisingly also for MV-photons, proton and carbon-ion beams. In a ...

journal_title：Physics in medicine and biology

authors： Rudek B,McNamara A,Ramos-Méndez J,Byrne H,Kuncic Z,Schuemann J

更新日期：2019-08-28 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：:The effect of temperature on the optical properties of human dermis and subdermis as a function of near-infrared wavelength has been studied between 25 degrees C and 40 degrees C. Measurements were performed ex vivo on a total of nine skin samples taken from the abdomen of three individuals. The results show a reprodu...

journal_title：Physics in medicine and biology

authors： Laufer J,Simpson R,Kohl M,Essenpreis M,Cope M

更新日期：1998-09-01 00:00:00

abstract：:The goals of this study were (1) to characterize the optical artefacts affecting measurement accuracy in a volumetric liquid scintillator detector, and (2) to develop methods to correct for these artefacts. The optical artefacts addressed were photon scattering, refraction, camera perspective, vignetting, lens distort...

journal_title：Physics in medicine and biology

authors： Robertson D,Hui C,Archambault L,Mohan R,Beddar S

更新日期：2014-01-06 00:00:00

abstract：:The aim of the study is to assess the staging value of the tumor heterogeneity characterized by texture features and other commonly used semi-quantitative indices extracted from (18)F-FDG PET images of cervical cancer (CC) patients. Forty-two patients suffering CC at different stages were enrolled in this study. First...

journal_title：Physics in medicine and biology

authors： Mu W,Chen Z,Liang Y,Shen W,Yang F,Dai R,Wu N,Tian J

更新日期：2015-07-07 00:00:00

abstract：:The aim of this study is to determine the impact of longitudinal micro-CT imaging on the growth of B16F1 tumours in C57BL/6 mice. Sixty mice received 2 × 10(5) B16F1 cells subcutaneously in the hind flank and were divided into control (no scan), 'low-dose' (80 kVp, 70 mA, 8 s, 0.07 Gy), 'medium-dose' (80 kVp, 50 mA, 3...

journal_title：Physics in medicine and biology

authors： Foster WK,Ford NL

更新日期：2011-01-21 00:00:00

abstract：:The reference levels for testing compliance of human exposure with radio-frequency (RF) safety limits have been derived from very simplified models of the human. In order to validate these findings for anatomical models, we investigated the absorption characteristics for various anatomies ranging from 6 year old child...

journal_title：Physics in medicine and biology

authors： Kühn S,Jennings W,Christ A,Kuster N

更新日期：2009-02-21 00:00:00

abstract：:A new multiplicative correction factor for tissue heterogeneities based on an exact expression for homogeneous non-unit-density media is proposed. O'Connor's density scaling theorem is invoked to evaluate the medium-specific tissue-maximum ratios used in the exact formulation. Monte Carlo calculations were performed a...

journal_title：Physics in medicine and biology

authors： Petti PL,Siddon RL,Bjärngard BE

更新日期：1986-10-01 00:00:00

abstract：:In this study we investigate light penetration into skin in order to define the optimal wavelength for the treatment of port wine stains. A two-layer model (epidermis and dermis) is applied with a cylindric tube representing the ectatic blood vessel. Light propagation is calculated by the Monte Carlo method. Values fo...

journal_title：Physics in medicine and biology

authors： Kienle A,Hibst R

更新日期：1995-10-01 00:00:00

abstract：:In modern radiotherapy, it is vitally important to monitor the performance of all linac components including the collimation system. In this study, a simple measurement method and accurate algorithm are introduced for investigation of the secondary and tertiary collimator sag during radiotherapy arc treatments. The me...

journal_title：Physics in medicine and biology

authors： Rowshanfarzad P,Sabet M,O'Connor DJ,Greer PB

更新日期：2012-06-21 00:00:00

abstract：:This work presents a Monte Carlo model of Leksell Gamma Knife Perfexion as well as the main parameters of the dose distribution in the standard phantom obtained using this model. The model is developed in the Geant4 simulation toolkit in a modular way which enables its reuse in other Perfexion studies. Large phase spa...

journal_title：Physics in medicine and biology

authors： Pipek J,Novotný J,Novotný J,Kozubíková P

更新日期：2014-12-21 00:00:00

abstract：:Lung 4D computed tomography (4D-CT), which is a time-resolved CT data acquisition, performs an important role in explicitly including respiratory motion in treatment planning and delivery. However, the radiation dose is usually reduced at the expense of inter-slice spatial resolution to minimize radiation-related heal...

journal_title：Physics in medicine and biology

authors： Fang S,Wang H,Liu Y,Zhang M,Yang W,Feng Q,Chen W,Zhang Y

更新日期：2017-10-03 00:00:00

abstract：:The optical properties (absorption and scattering coefficients and the scattering anisotropy factor) were measured in vitro for cartilage, liver, lung, muscle, myocardium, skin, and tumour (colon adenocarcinoma CC 531) at 630, 632.8, 790, 850 and 1064 nm. Rabbits, rats, piglets, goats, and dogs were used to obtain the...

journal_title：Physics in medicine and biology

authors： Beek JF,Blokland P,Posthumus P,Aalders M,Pickering JW,Sterenborg HJ,van Gemert MJ

更新日期：1997-11-01 00:00:00

abstract：:Stereotactic Gamma Knife radiosurgery utilizes ionizing beams from (60)Co sources and relies on a combination of collimator sizes, weighting, etc to generate a high-dose region that is conformal with a designated target volume. Dose computation is typically performed by computer, but in this paper, single collimator d...

journal_title：Physics in medicine and biology

authors： Fenner J,Gwilliam M,Mehrem R,Bird A,Walton L

更新日期：2008-04-21 00:00:00

abstract：:Dose factors for locations within a tissue-filled cylindrical cavity bounded by an infinite medium of bone labelled with an alpha-emitter are calculated by means of a Monte Carlo procedure. The calculational approach is general and allows us to determine dose factors for specific distances or target volumes defined by...

journal_title：Physics in medicine and biology

authors： Polig E

更新日期：1989-03-01 00:00:00

abstract：:This is a review of the relatively recently developed field of intravascular brachytherapy of coronary arteries. It presents a brief overview of the discipline of coronary angioplasty describing the problem of restenosis and discusses the potential for ionizing radiation to overcome this problem. It examines the vario...

journal_title：Physics in medicine and biology

authors： Fox RA

更新日期：2002-02-21 00:00:00

abstract：:In modern radiotherapy the verification of complex treatments plans is often performed in inhomogeneous or even anthropomorphic phantoms. For dose verification small detectors are necessary and therefore alanine detectors are most suitable. Though the response of alanine for a wide range of clinical photon energies in...

journal_title：Physics in medicine and biology

authors： von Voigts-Rhetz P,Anton M,Vorwerk H,Zink K

更新日期：2016-02-07 00:00:00

abstract：:Diffraction-enhanced imaging (DEI) is a new x-ray imaging modality that has been shown to enhance contrast between normal and cancerous breast tissues. In this study, diffraction-enhanced imaging in computed tomography (DEI-CT) mode was used to quantitatively characterize the refraction contrasts of the organized stru...

journal_title：Physics in medicine and biology

authors： Kao T,Connor D,Dilmanian FA,Faulconer L,Liu T,Parham C,Pisano ED,Zhong Z

更新日期：2009-05-21 00:00:00

abstract：:The low energy model of the GEANT4 Monte Carlo toolkit was used to simulate the energy response of a T.P.A. Mk-II ionization chamber under a variety of different conditions. The sample position resulting in the maximum response along the axial direction of the chamber was obtained. The parameters of the simulation wer...

journal_title：Physics in medicine and biology

authors： Seneviratne MD,Reinhard MI,Baldock C

更新日期：2007-07-07 00:00:00

abstract：:Measurements of patient entrance surface dose rate provide valuable data for interpreting results from dose-area product studies on fluoroscopic x-ray equipment. Methods for measurement of entrance surface dose rate with backscatter and incident dose rate without backscatter have been investigated. Entrance surface do...

journal_title：Physics in medicine and biology

authors： Martin CJ

更新日期：1995-05-01 00:00:00

abstract：:Grating-based x-ray phase-contrast imaging provides three simultaneous image channels originating from a single image acquisition. While the phase signal provides direct access to the electron density in tomography, there is additional information on sub-resolutional structural information which is called dark-field s...

journal_title：Physics in medicine and biology

authors： Braig EM,Pfeiffer D,Willner M,Sellerer T,Taphorn K,Petrich C,Scholz J,Petzold L,Birnbacher L,Dierolf M,Pfeiffer F,Herzen J

更新日期：2020-09-18 00:00:00

abstract：:This paper contains the recommendations of the high dose rate (HDR) brachytherapy working party of the UK Institute of Physics and Engineering in Medicine (IPEM). The recommendations consist of a Code of Practice (COP) for the UK for measuring the reference air kerma rate (RAKR) of HDR (192)Ir brachytherapy sources. I...

journal_title：Physics in medicine and biology

authors： Bidmead AM,Sander T,Locks SM,Lee CD,Aird EG,Nutbrown RF,Flynn A,IPEM Working Party.

更新日期：2010-06-07 00:00:00

abstract：:Using iterative three-dimensional (3D) reconstruction techniques for reconstruction of positron emission tomography (PET) is not feasible on most single-processor machines due to the excessive computing time needed, especially so for the large sinogram sizes of our high-resolution research tomograph (HRRT). In our fir...

journal_title：Physics in medicine and biology

authors： Vollmar S,Michel C,Treffert JT,Newport DF,Casey M,Knöss C,Wienhard K,Liu X,Defrise M,Heiss WD

更新日期：2002-08-07 00:00:00

abstract：:Nanocarriers offer a promising approach to significantly improve therapeutic delivery to solid tumors as well as limit the side effects associated with anti-cancer agents. However, their relatively large size can negatively affect their ability to efficiently penetrate into more interior tumor regions, ultimately redu...

journal_title：Physics in medicine and biology

authors： Mohammadabadi A,Huynh RN,Wadajkar AS,Lapidus RG,Kim AJ,Raub CB,Frenkel V

更新日期：2020-06-22 00:00:00

abstract：:This study evaluated the cavitation activity induced by shock wave (SW) pulses, both in vitro and in vivo, based on the area measurements of echogenic regions observed in B-mode ultrasound images. Residual cavitation bubble clouds induced by SW pulses were detected as echogenic regions in B-mode images. The temporal e...

journal_title：Physics in medicine and biology

authors： Tu J,Matula TJ,Bailey MR,Crum LA

更新日期：2007-10-07 00:00:00

abstract：:For low-energy (up to 150 kV) x-rays, the ratio of mass-energy absorption coefficients for water to air, (mu(en)/rho)w.air, and the backscatter factor B are used in the conversion of air kerma, measured free-in-air, to water kerma on the surface of a water phantom. For clinical radiotherapy, similar conversion factors...

journal_title：Physics in medicine and biology

authors： Ma CM,Seuntjens JP

更新日期：1999-01-01 00:00:00

abstract：:Catheter-based ultrasound devices provide a method to deliver 3D conformable heating integrated with HDR brachytherapy delivery. Theoretical characterization of heating patterns was performed to identify implant strategies for these devices which can best be used to apply hyperthermia to cervical cancer. A constrained...

journal_title：Physics in medicine and biology

authors： Wootton JH,Prakash P,Hsu IC,Diederich CJ

更新日期：2011-07-07 00:00:00