Effect on tumour control of time interval between surgery and postoperative radiotherapy: an empirical approach using Monte Carlo simulation.

abstract：:K-edge subtraction (KES) imaging is a technique able to map a specific element such as e.g. a contrast agent within the tissues, by exploiting the sharp rise of its absorption coefficient at the K-edge energy. Whereas mainly explored at synchrotron radiation sources, the energy discrimination properties of modern x-ra...

journal_title：Physics in medicine and biology

authors： Brun F,Di Trapani V,Albers J,Sacco P,Dreossi D,Brombal L,Rigon L,Longo R,Mittone A,Dullin C,Bravin A,Delogu P

更新日期：2020-03-06 00:00:00

abstract：:We present a method to include robustness in a multi-criteria optimization (MCO) framework for intensity-modulated proton therapy (IMPT). The approach allows one to simultaneously explore the trade-off between different objectives as well as the trade-off between robustness and nominal plan quality. In MCO, a database...

journal_title：Physics in medicine and biology

authors： Chen W,Unkelbach J,Trofimov A,Madden T,Kooy H,Bortfeld T,Craft D

更新日期：2012-02-07 00:00:00

abstract：:Despite over ten years of in vitro investigations of ultrasound contrast agents, the level of understanding of their behaviour in ultrasound fields is limited. Several problems associated with these investigations, particular to the nature of contrast agents, are discussed. Using a commercial scanner the RF normalized...

journal_title：Physics in medicine and biology

authors： Sboros V,Ramnarine KV,Moran CM,Pye SD,McDicken WN

更新日期：2002-12-07 00:00:00

abstract：:Segmentation is often required for the analysis of dynamic positron emission tomography (PET) images. However, noise and low spatial resolution make it a difficult task and several supervised and unsupervised methods have been proposed in the literature to perform the segmentation based on semi-automatic clustering of...

journal_title：Physics in medicine and biology

authors： Mouysset S,Zbib H,Stute S,Girault JM,Charara J,Noailles J,Chalon S,Buvat I,Tauber C

更新日期：2013-10-07 00:00:00

abstract：:A phantom study was performed in full-field digital mammography to investigate the opportunity and the magnitude of a possible dose reduction that would leave the image quality above the accepted thresholds associated with some classical phantoms. This preliminary work is intended to lay the groundwork for a future cl...

journal_title：Physics in medicine and biology

authors： Gennaro G,Katz L,Souchay H,Alberelli C,di Maggio C

更新日期：2005-04-21 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：:To monitor and strategically control energy deposition in magnetic resonance imaging (MRI), measured as a specific absorption rate (SAR), numerical methods using generic human models have been employed to estimate worst-case values. Radiofrequency (RF) sequences are therefore often designed conservatively with large s...

journal_title：Physics in medicine and biology

authors： Jin J,Liu F,Weber E,Crozier S

更新日期：2012-12-21 00:00:00

abstract：:Kilovoltage intratreatment monitoring (KIM) is a novel real-time localization modality where the tumor position is continuously measured during intensity modulated radiation therapy (IMRT) or intensity modulated arc therapy (IMAT) by a kilovoltage (kV) x-ray imager. Adding kV imaging during therapy adds radiation dose...

journal_title：Physics in medicine and biology

authors： Ng JA,Booth J,Poulsen P,Kuncic Z,Keall PJ

更新日期：2013-09-07 00:00:00

abstract：:A common dose-saving technique used in modern CT devices is automatic tube current modulation (TCM), which was originally designed to also reduce the dose in paediatric CT patients. In order to be able to deduce detailed organ doses of paediatric models, dose conversion coefficients normalized to CTDI(vol) for an eigh...

journal_title：Physics in medicine and biology

authors： Schlattl H,Zankl M,Becker J,Hoeschen C

更新日期：2012-10-21 00:00:00

abstract：:A method for the calculation of absorbed dose distributions of arbitrarily shaped electron beams is presented. Isodose distributions and output factors of treatment fields can be predicted with good accuracy, without the need for any dose measurement in the actual field. A Gaussian pencil beam model is employed with t...

journal_title：Physics in medicine and biology

authors： Bruinvis IA,Van Amstel A,Elevelt AJ,Van der Laarse R

更新日期：1983-06-01 00:00:00

abstract：:Large blood vessels can produce steep temperature gradients in heated tissues leading to inadequate tissue temperatures during hyperthermia. This paper utilizes a finite difference scheme to solve the basic equations of heat transfer and fluid flow to model blood vessel cooling. Unlike previous formulations, heat tran...

journal_title：Physics in medicine and biology

authors： Kolios MC,Sherar MD,Hunt JW

更新日期：1995-04-01 00:00:00

abstract：:Several methods of flip angle mapping for magnetic resonance imaging have been proposed. We evaluated the accuracy of five methods of flip angle measurement in the presence of measurement noise. Our analysis was performed in a closed form by propagation of probability density functions (PDFs). The flip angle mapping m...

journal_title：Physics in medicine and biology

authors： Morrell GR,Schabel MC

更新日期：2010-10-21 00:00:00

abstract：:Rotational coronary angiography provides a multitude of x-ray projections of the contrast agent enhanced coronary arteries along a given trajectory with parallel ECG recording. These data can be used to derive motion information of the coronary arteries including vessel displacement and pulsation. In this paper, a ful...

journal_title：Physics in medicine and biology

authors： Jandt U,Schäfer D,Grass M,Rasche V

更新日期：2009-01-07 00:00:00

abstract：:Images of the human retina are routinely used in clinical practice for the diagnosis and management of eye disease. Increased permeability of retinal blood vessels, which is a clinically significant feature, can be visualized with a process known as fluorescein angiography as leakage of fluorescence dye into the surro...

journal_title：Physics in medicine and biology

authors： Cree MJ,Olson JA,McHardy KC,Sharp PF,Forrester JV

更新日期：1999-01-01 00:00:00

abstract：:Statistically based iterative image reconstruction methods have been developed for emission tomography. One important component in iterative image reconstruction is the system matrix, which defines the mapping from the image space to the data space. Several groups have demonstrated that an accurate system matrix can i...

journal_title：Physics in medicine and biology

authors： Qi J,Huesman RH

更新日期：2005-07-21 00:00:00

abstract：:Gold nanoparticles (GNPs) have shown potential in recent years as a means of therapeutic dose enhancement in radiation therapy. However, a major challenge in moving towards clinical implementation is the exact characterisation of the dose enhancement they provide. Monte Carlo studies attempt to explore this property, ...

journal_title：Physics in medicine and biology

authors： Koger B,Kirkby C

更新日期：2016-03-07 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：:We extend the theory of three-dimensional (3D) tomographic intensity modulated radiation therapy (IMRT). The geometry consists of two-dimensional modulated beams on a sphere centred in the tumour. The theory provides an efficient algorithm for computing beam modulation patterns that approximately 'reconstruct' the pre...

journal_title：Physics in medicine and biology

authors： Levine RY,Braunstein M

更新日期：2002-03-07 00:00:00

abstract：:RapidArc, recently released by Varian Medical Systems, is a novel extension of IMRT in which an optimized 3D dose distribution may be delivered in a single gantry rotation of 360 degrees or less. The purpose of this study was to investigate the accuracy of the analytical anisotropic algorithm (AAA), the sole algorithm...

journal_title：Physics in medicine and biology

authors： Gagne IM,Ansbacher W,Zavgorodni S,Popescu C,Beckham WA

更新日期：2008-12-21 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：:We developed an anatomy-guided 4D closed-form algorithm to directly reconstruct parametric images from projection data for (nearly) irreversible tracers. Conventional methods consist of individually reconstructing 2D/3D PET data, followed by graphical analysis on the sequence of reconstructed image frames. The propose...

journal_title：Physics in medicine and biology

authors： Tang J,Kuwabara H,Wong DF,Rahmim A

更新日期：2010-08-07 00:00:00

abstract：:Margins are employed in radiotherapy treatment planning to mitigate the dosimetric effects of geometric uncertainties for the clinical target volume (CTV). Unfortunately, whilst the use of margins can increase the probability that sufficient dose is delivered to the CTV, it can also result in delivering high dose of r...

journal_title：Physics in medicine and biology

authors： Tsang HS,Kamerling CP,Ziegenhein P,Nill S,Oelfke U

更新日期：2018-10-29 00:00:00

abstract：:Using Monte Carlo simulation of 99Tcm single-photon-emission computed tomography (SPECT), we investigate the effects of tissue-background activity, tumour location, patient size, uncertainty of energy windows, and definition of tumour region on the accuracy of quantification. The dual-energy-window method of correctio...

journal_title：Physics in medicine and biology

authors： Luo JQ,Koral KF,Ljungberg M,Floyd CE Jr,Jaszczak RJ

更新日期：1995-01-01 00:00:00

abstract：:A circular scanning trajectory is and will likely remain a popular choice of trajectory in computed tomography (CT) imaging because it is easy to implement and control. Filtered-backprojection (FBP)-based algorithms have been developed previously for approximate and exact reconstruction of the entire image or a region...

journal_title：Physics in medicine and biology

authors： Pan X,Xia D,Zou Y,Yu L

更新日期：2004-09-21 00:00:00

abstract：:Lymphedema is a common condition involving an abnormal accumulation of lymphatic fluid in the interstitial space that causes swelling, most often in the arm(s) and leg(s). Lymphedema is a significant lifelong concern that can be congenital or develop following cancer treatment or cancer metastasis. Common methods of e...

journal_title：Physics in medicine and biology

authors： Righetti R,Garra BS,Mobbs LM,Kraemer-Chant CM,Ophir J,Krouskop TA

更新日期：2007-11-07 00:00:00

abstract：:Dose calculation for radiotherapy with protons and heavier ions deals with a large volume of path integrals involving a scattering power of body tissue. This work provides a simple model for such demanding applications. There is an approximate linearity between RMS end-point displacement and range of incident particle...

journal_title：Physics in medicine and biology

authors： Kanematsu N

更新日期：2009-03-07 00:00:00

abstract：:Hair loss is a feared side effect of chemotherapy treatment. It may be prevented by cooling the scalp during administration of cytostatics. The supposed mechanism is that by cooling the scalp, both temperature and perfusion are diminished, affecting drug supply and drug uptake in the hair follicle. However, the effect...

journal_title：Physics in medicine and biology

authors： Janssen FE,Van Leeuwen GM,Van Steenhoven AA

更新日期：2005-09-07 00:00:00

abstract：:Micro-CT is widely used in preclinical studies, generating substantial interest in extending its capabilities in functional imaging applications such as blood perfusion and cardiac function. However, imaging cardiac structure and function in mice is challenging due to their small size and rapid heart rate. To overcome...

journal_title：Physics in medicine and biology

authors： Holbrook M,Clark DP,Badea CT

更新日期：2018-01-09 00:00:00

abstract：:A finite element thermal model of the head has been developed to calculate temperature rises generated in the brain by radiation from cellular telephones and similar electromagnetic devices. A 1 mm resolution MRI dataset was segmented semiautomatically, assigning each volume element to one of ten tissue types. A finit...

journal_title：Physics in medicine and biology

authors： Wainwright P

更新日期：2000-08-01 00:00:00

abstract：:As automation in radiation oncology becomes more common, it is important to determine which algorithms are equivalent for a given workflow. Often, algorithm comparisons are performed in isolation; however, clinical context can provide valuable insight into the importance of algorithm features and error magnification i...

journal_title：Physics in medicine and biology

authors： Weppler S,Schinkel C,Kirkby C,Smith W

更新日期：2020-09-28 00:00:00