Quality assurance in brachytherapy: the displacement effect in the vicinity of 60Co and 192Ir brachytherapy sources.

abstract：:Intensity modulated radiation therapy (IMRT) inverse planning using total-variation (TV) regularization has been proposed to reduce the complexity of fluence maps and facilitate dose delivery. Conventionally, the optimization problem with L-1 norm is solved with quadratic programming (QP), which is time consuming and ...

journal_title：Physics in medicine and biology

authors： Kim H,Suh TS,Lee R,Xing L,Li R

更新日期：2012-07-07 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：:A new system has been designed and built to validate the concept of 3D computerized angiography (CA). This system can acquire a set of 2D digital subtracted angiography images while rotating around a patient and then, using these images, reconstruct a 3D representation of the opacified vasculature. The design principl...

journal_title：Physics in medicine and biology

authors： Saint-Félix D,Trousset Y,Picard C,Ponchut C,Roméas R,Rougée A

更新日期：1994-03-01 00:00:00

abstract：:In this paper, we present a new algorithm as an enhancement and preprocessing step for acquired optical coherence tomography (OCT) images of the retina. The proposed method is composed of two steps, first of which is a denoising algorithm with wavelet diffusion based on a circular symmetric Laplacian model, and the se...

journal_title：Physics in medicine and biology

authors： Kafieh R,Rabbani H,Abramoff MD,Sonka M

更新日期：2013-05-07 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：:Evaluation of the radioisotopic purity of technetium-99m (99mTc) produced in GBq amounts by proton bombardment of enriched molibdenum-100 (100Mo) metallic targets at low proton energies (i.e. within 15-20 MeV) is conducted. This energy range was chosen since it is easily achievable by many conventional medical cyclotr...

journal_title：Physics in medicine and biology

authors： Uzunov NM,Melendez-Alafort L,Bello M,Cicoria G,Zagni F,De Nardo L,Selva A,Mou L,Rossi-Alvarez C,Pupillo G,Di Domenico G,Uccelli L,Boschi A,Groppi F,Salvini A,Taibi A,Duatti A,Martini P,Pasquali M,Loriggiola M,Mare

更新日期：2018-09-19 00:00:00

abstract：:Echocardiography (echo) is a widely available method to obtain images of the heart; however, echo can suffer due to the presence of artefacts, high noise and a restricted field of view. One method to overcome these limitations is to use multiple images, using the 'best' parts from each image to produce a higher qualit...

journal_title：Physics in medicine and biology

authors： Yao C,Simpson JM,Schaeffter T,Penney GP

更新日期：2011-09-21 00:00:00

abstract：:Determining accurate in vivo dosimetry in brachytherapy treatment with high dose gradients is challenging. Here we introduce, investigate, and characterize a novel in vivo dosimeter and readout technique with the potential to address this problem. A cylindrical (4 mm × 20 mm) tissue equivalent radiochromic dosimeter P...

journal_title：Physics in medicine and biology

authors： Vidovic AK,Juang T,Meltsner S,Adamovics J,Chino J,Steffey B,Craciunescu O,Oldham M

更新日期：2014-07-21 00:00:00

abstract：:Radiotherapy treatment planning is associated with uncertainties. Examples are uncertainties in the tumour location due to organ movement or the inter/intra observer variability in target definition. Different approaches to incorporate uncertainties into IMRT optimization have been proposed. In this note, we point out...

journal_title：Physics in medicine and biology

authors： Unkelbach J,Oelfke U

更新日期：2006-12-07 00:00:00

abstract：:Several recent reports agree that the potentially dangerous heating around extended wires or coaxial cables inside the bodycoil of a magnetic resonance imager is related to resonant effects. No quantitative description of this idea has been given so far. We analyse a simplified situation, where a straight metallic wir...

journal_title：Physics in medicine and biology

authors： Pictet J,Meuli R,Wicky S,van der Klink JJ

更新日期：2002-08-21 00:00:00

abstract：:It is well known that the experimental dosimetry of brachytherapy sources presents a challenge. Depending on the particular-dosimeter used, measurements can suffer from poor spatial resolution (ion chambers), lack of 3D information (film) or errors due to the presence of the dosimeter itself distorting the radiation f...

journal_title：Physics in medicine and biology

authors： McJury M,Tapper PD,Cosgrove VP,Murphy PS,Griffin S,Leach MO,Webb S,Oldham M

更新日期：1999-10-01 00:00:00

abstract：:We propose a hybrid multiobjective (MO) evolutionary optimization algorithm (MOEA) for intensity-modulated radiotherapy inverse planning and apply it to optimize the number of incident beams, their orientations and intensity profiles. The algorithm produces a set of efficient solutions, which represent different clini...

journal_title：Physics in medicine and biology

authors： Schreibmann E,Lahanas M,Xing L,Baltas D

更新日期：2004-03-07 00:00:00

abstract：:Recent studies have demonstrated the feasibility of transcranial high-intensity focused ultrasound (HIFU) therapy in the brain using adaptive focusing techniques. However, the complexity of the procedures imposes provision of accurate targeting, monitoring and control of this emerging therapeutic modality in order to ...

journal_title：Physics in medicine and biology

authors： Larrat B,Pernot M,Aubry JF,Dervishi E,Sinkus R,Seilhean D,Marie Y,Boch AL,Fink M,Tanter M

更新日期：2010-01-21 00:00:00

abstract：:The purpose of this investigation is to propose new compensator design strategies for protons and heavier particles which are based on pencil-beam (PB) dose calculations and which significantly reduce the dose to tissues downstream from the target, yet provide acceptable target coverage under conditions of patient mot...

journal_title：Physics in medicine and biology

authors： Petti PL

更新日期：1997-07-01 00:00:00

abstract：:In vitro dielectric properties of ageing porcine tissues were measured in the frequency range of 50 MHz-20 GHz, and the total combined uncertainties of the measurements were assessed. The results show statistically significant reduction with age in both permittivity and conductivity of 10 out of 15 measured tissues. A...

journal_title：Physics in medicine and biology

authors： Peyman A,Gabriel C,Grant EH,Vermeeren G,Martens L

更新日期：2009-01-21 00:00:00

abstract：:An experimental investigation of the central axis depth-dose and stopping rate distribution of the SIN biomedical pion beam is reported. The pion stopping rate in a thin disc of tissue-equivalent plastic was determined using a counter telescope. The dose rate at the position of this dic 'target' was measured using a s...

journal_title：Physics in medicine and biology

authors： Nordell B,Baarli J,Sullivan AH,Zielczynski M

更新日期：1977-05-01 00:00:00

abstract：:This paper concerns the robustness of discrete wavelet transform (DWT) compression in terahertz pulsed imaging (TPI). TPI datasets consist of terahertz time-domain series which are sampled at each 'pixel' of the image, leading to file sizes which are typically of the order of several megabytes (MB) per image. This mak...

journal_title：Physics in medicine and biology

authors： Handley JW,Fitzgerald AJ,Berry E,Boyle RD

更新日期：2002-11-07 00:00:00

abstract：:Fluorescence molecular imaging/tomography may play an important future role in preclinical research and clinical diagnostics. Time- and frequency-domain fluorescence imaging can acquire more measurement information than the continuous wave (CW) counterpart, improving the image quality of fluorescence molecular tomogra...

journal_title：Physics in medicine and biology

authors： Lu Y,Zhu B,Shen H,Rasmussen JC,Wang G,Sevick-Muraca EM

更新日期：2010-08-21 00:00:00

abstract：:Contrast-enhanced ultrasound (US) imaging is potentially applicable to the investigation of vascular disorders of the testis. We investigated the ability of two automated computer algorithms to analyse contrast-enhanced pulse inversion US data in a rabbit model of unilateral testicular ischaemia and to correctly deter...

journal_title：Physics in medicine and biology

authors： Thierman JS,Clement GT,Kalish LA,O'Kane PL,Frauscher F,Paltiel HJ

更新日期：2006-07-21 00:00:00

abstract：:The objective of this work is to test analytical models to calculate the luminescence efficiency of Al(2)O(3):C optically stimulated luminescence detectors (OSLDs) exposed to heavy charged particles with energies relevant to space dosimetry and particle therapy. We used the track structure model to obtain an analytica...

journal_title：Physics in medicine and biology

authors： Sawakuchi GO,Yukihara EG

更新日期：2012-01-21 00:00:00

abstract：:A standard protocol for performance evaluation of positron emission mammography (PEM) systems has not yet been established. In this work we propose a methodology based on the design of specific phantoms for this imaging modality with component dimensions in accordance with typical breast lesion sizes together with the...

journal_title：Physics in medicine and biology

authors： Torres-Urzúa LF,Alva-Sanchez H,Martinez-Davalos A,García-Pérez FO,Peruyero-Rivas RM,Rodriguez-Villafuerte M

更新日期：2020-07-21 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：:In this note a technique is described for direct aperture optimization of components deliverable by a variable aperture collimator (VAC) for intensity-modulated radiation therapy. The first key result found was that, provided a large number of VAC components were selected for optimization, the resulting fluence profil...

journal_title：Physics in medicine and biology

authors： Webb S

更新日期：2004-03-07 00:00:00

abstract：:We developed and validated a Monte-Carlo-based application (RAYDOSE) to generate patient-specific 3D dose maps on the basis of pre-treatment imaging studies. A CT DICOM image is used to model patient geometry, while repeated PET scans are employed to assess radionuclide kinetics and distribution at the voxel level. In...

journal_title：Physics in medicine and biology

authors： Marcatili S,Pettinato C,Daniels S,Lewis G,Edwards P,Fanti S,Spezi E

更新日期：2013-04-21 00:00:00

abstract：:The free space method using a pair of lens antennas was modified for the complex permittivity measurement of biological samples from 20 to 110 GHz. Two methodologies were used to obtain the complex permittivities by the free space method, which were based on the reflection and transmission coefficients. The measuremen...

journal_title：Physics in medicine and biology

authors： Sasaki K,Segawa H,Mizuno M,Wake K,Watanabe S,Hashimoto O

更新日期：2013-03-07 00:00:00

abstract：:Magnetic particle imaging is a new approach to visualizing magnetic nanoparticles. It is capable of 3D real-time in vivo imaging of particles injected into the blood stream and is a candidate for medical imaging applications. To date, only one particle type has been imaged at a time, however, the ability to separate s...

journal_title：Physics in medicine and biology

authors： Rahmer J,Halkola A,Gleich B,Schmale I,Borgert J

更新日期：2015-03-07 00:00:00

abstract：:A semi-empirical theory has been derived that relates the aluminum equivalence of various materials used in diagnostic radiology to their attenuation coefficients. The dependence of the aluminum hardness (AHE) and attenuation (AAE) equivalent on the beam quality is described in terms of effective energy. This 'aluminu...

journal_title：Physics in medicine and biology

authors： Nagel HD

更新日期：1986-12-01 00:00:00

abstract：:An experimental determination of the energy correction factor for alanine/paraffin pellets in the 192Ir spectrum at varying distances from the source is presented. Alanine dosimeters were irradiated in water under full scatter conditions with a high dose rate (HDR) 192Ir source (Flexisource), using a dedicated holder....

journal_title：Physics in medicine and biology

authors： Schaeken B,Cuypers R,Goossens J,Van den Weyngaert D,Verellen D

更新日期：2011-10-21 00:00:00

abstract：:A leaf-setting algorithm is developed for generating arbitrary beam intensity profiles in discrete levels using dynamic multileaf collimators (DMLCs). The algorithm starts with the algebraic expression for the area under the beam profile. It is shown that the coefficients in this expression can be transformed into the...

journal_title：Physics in medicine and biology

authors： Ma L,Boyer AL,Xing L,Ma CM

更新日期：1998-06-01 00:00:00