Improved dose-calculation accuracy in proton treatment planning using a simplified Monte Carlo method verified with three-dimensional measurements in an anthropomorphic phantom.

abstract：:To investigate the profile measurement capabilities of an IBA-Dosimetry scintillation detector and to assess its feasibility for determining the low-intensity tails of pencil-beam scanning spots, the responses of the scintillation detector and Gafchromic EBT2 film to a 115 MeV proton spot were measured in-air at the i...

journal_title：Physics in medicine and biology

authors： Lin L,Ainsley CG,Mertens T,De Wilde O,Talla PT,McDonough JE

更新日期：2013-06-21 00:00:00

abstract：:The purpose of this study is to explain the unplanned longitudinal dose modulations that appear in helical tomotherapy (HT) dose distributions in the presence of irregular patient breathing. This explanation is developed by the use of longitudinal (1D) simulations of mock and surrogate data and tested with a fully 4D ...

journal_title：Physics in medicine and biology

authors： Kissick MW,Flynn RT,Westerly DC,Hoban PW,Mo X,Soisson ET,McCall KC,Mackie TR,Jeraj R

更新日期：2008-09-21 00:00:00

abstract：:In dynamic renal scintigraphy, the main interest is the radiopharmaceutical redistribution as a function of time. Quality control (QC) of renal procedures often relies on phantom experiments to compare image-based results with the measurement setup. A phantom with a realistic anatomy and time-varying activity distribu...

journal_title：Physics in medicine and biology

authors： Brolin G,Gleisner KS,Ljungberg M

更新日期：2013-05-21 00:00:00

abstract：:An ultrahigh-resolution full-field optical coherence tomography (OCT) system has been developed for cellular-level imaging of biological media. The system is based on a Linnik interference microscope illuminated with a tungsten halogen lamp, associated with a high-resolution CCD camera. En face tomographic images are ...

journal_title：Physics in medicine and biology

authors： Dubois A,Moneron G,Grieve K,Boccara AC

更新日期：2004-04-07 00:00:00

abstract：:Modern digital radiographic 'flat panel' detectors can exhibit a progressive form of image degradation arising from non-functioning pixels. The effect of these 'dead pixels' on the quantitive image quality measures of modulation transfer function (MTF), noise power spectrum (NPS) and detective quantum efficiency (DQE)...

journal_title：Physics in medicine and biology

authors： Padgett R,Kotre CJ

更新日期：2004-03-21 00:00:00

abstract：:W (the average energy to form an ion pair) for 5.4 MeV 241Am alpha particles in a Rossi-type tissue-equivalent (TE) gas, argon and methane was determined to an accuracy better than 0.2% using a new automated data handling system. A vibrating reed electrometer and current digitiser were used to measure the current prod...

journal_title：Physics in medicine and biology

authors： Krieger GL,Baum JW,Varma MN,Beach JL

更新日期：1979-03-01 00:00:00

abstract：:The purpose of this study is to develop an adaptive prior knowledge guided image estimation technique to reduce the scan angle needed in the limited-angle intrafraction verification (LIVE) system for 4D-CBCT reconstruction. The LIVE system has been previously developed to reconstruct 4D volumetric images on-the-fly du...

journal_title：Physics in medicine and biology

authors： Zhang Y,Yin FF,Zhang Y,Ren L

更新日期：2017-05-07 00:00:00

abstract：:For conventional irradiation devices, the radiation isocenter accuracy is determined by star shot measurements on films. In magnetic resonance (MR)-guided radiotherapy devices, the results of this test may be altered by the magnetic field and the need to align the radiation and imaging isocenter may require a modifica...

journal_title：Physics in medicine and biology

authors： Dorsch S,Mann P,Lang C,Haering P,Runz A,Karger CP

更新日期：2018-05-29 00:00:00

abstract：:This paper describes a neural network (NN) regression model for relative dose computation. The input signal of the NN model includes depths and field sizes and the output is the relative dose, for example, percentage depth dose (%DD) or tissue-air ratio (TAR) in this paper. After a functional link has been created, th...

journal_title：Physics in medicine and biology

authors： Wu X,Zhu Y

更新日期：2000-04-01 00:00:00

abstract：:We present an automatic bi-objective parameter-tuning approach for inverse planning methods for high-dose-rate prostate brachytherapy, which aims to overcome the difficult and time-consuming manual parameter tuning that is currently required to obtain patient-specific high-quality treatment plans. We modelled treatmen...

journal_title：Physics in medicine and biology

authors： Maree SC,Bosman PAN,van Wieringen N,Niatsetski Y,Pieters BR,Bel A,Alderliesten T

更新日期：2020-04-02 00:00:00

abstract：:A simple and fast, but sensitive TLD method for the measurement of energy and homogeneity of therapeutically used electron beams has been developed and tested. This method is based on the fact that when small thicknesses of high-Z absorbers such as lead are interposed in the high-energy electron beams, the transmitted...

journal_title：Physics in medicine and biology

authors： Pradhan AS,Quast U,Sharma PK

更新日期：1994-09-01 00:00:00

abstract：:A correction for loss of events due to dead time in dynamic positron emission tomography (PET) is presented. The model employs a paralysing dead time to describe the behaviour of a tomograph over the range of event rates normally encountered in patient studies (up to 200 000 events/s per detector layer). The Donner 28...

journal_title：Physics in medicine and biology

authors： Mazoyer BM,Roos MS,Huesman RH

更新日期：1985-05-01 00:00:00

abstract：:A multimodal micro-computed tomography (CT) and multi-spectral structured light imaging (SLI) system is introduced and systematically analyzed to test its feasibility to aid in margin delineation during breast conserving surgery (BCS). Phantom analysis of the micro-CT yielded a signal-to-noise ratio of 34, a contrast ...

journal_title：Physics in medicine and biology

authors： McClatchy DM,Rizzo EJ,Meganck J,Kempner J,Vicory J,Wells WA,Paulsen KD,Pogue BW

更新日期：2017-11-10 00:00:00

abstract：:The purpose of this work was to study and quantify the differences in dose distributions computed with some of the newest dose calculation algorithms available in commercial planning systems. The study was done for clinical cases originally calculated with pencil beam convolution (PBC) where large density inhomogeneit...

journal_title：Physics in medicine and biology

authors： Hasenbalg F,Neuenschwander H,Mini R,Born EJ

更新日期：2007-07-07 00:00:00

abstract：:The classical Sievert integral method is a valuable tool for dose rate calculations around brachytherapy sources, combining simplicity with reasonable computational times. However, its accuracy in predicting dose rate anisotropy around 192Ir brachytherapy sources has been repeatedly put into question. In this work, we...

journal_title：Physics in medicine and biology

authors： Karaiskos P,Angelopoulos A,Baras P,Rozaki-Mavrouli H,Sandilos P,Vlachos L,Sakelliou L

更新日期：2000-02-01 00:00:00

abstract：:An original method for the analysis of oscillations of cutaneous blood flow has been developed, which makes use of laser Doppler flowmetry (LDF) data and is based on the continuous wavelet transform and adaptive wavelet theory. The potential of the method has been demonstrated in experiments with the response of micro...

journal_title：Physics in medicine and biology

authors： Tankanag A,Chemeris N

更新日期：2008-11-07 00:00:00

abstract：:The diagnosis of hepatocellular carcinoma (HCC) usually occurs at late stages in the disease when there are few effective treatment options. The measurement of the concentration of tumour markers in the serum of patients is a complementary tool frequently used for the interpretation of diagnostic imaging results. It i...

journal_title：Physics in medicine and biology

authors： Elshemey WM,Desouky OS,Mohammed MS,Elsayed AA,el-Houseini ME

更新日期：2003-09-07 00:00:00

abstract：:In electron beam dosimetry using parallel-plate chambers solid phantoms are sometimes necessary. To obtain the dose to water from the ionization obtained in the solid phantom, fluence correction factors and perturbation factors have to be applied. In this study fluence factors in a perturbation free geometry have been...

journal_title：Physics in medicine and biology

authors： Nilsson B,Montelius A,Andreo P,Johansson J

更新日期：1997-11-01 00:00:00

abstract：:This study investigates the oxygen mass transport in the region around the human carotid bifurcation, particularly addressing the effects of bifurcation geometry and pulsatile blood flow on the oxygen transport between the blood flow and artery wall tissue, coupled with the metabolic oxygen consumption and oxygen diff...

journal_title：Physics in medicine and biology

authors： Tada S

更新日期：2010-07-21 00:00:00

abstract：:Stroke lesion volume is a key radiologic measurement in assessing prognosis of acute ischemic stroke (AIS) patients. The aim of this paper is to develop an automated segmentation method for accurately segmenting follow-up ischemic and hemorrhagic lesion from multislice non-contrast CT (NCCT) volumes of AIS patients. T...

journal_title：Physics in medicine and biology

authors： Kuang H,Menon BK,Qiu W

更新日期：2020-11-05 00:00:00

abstract：:We model the heterogeneous response to radiation of multicellular tumour spheroids assuming position- and volume-dependent radiosensitivity. We propose a method to calculate the overall radiosensitivity parameters to obtain the surviving fraction of tumours. A mathematical model of a spherical tumour with a hypoxic co...

journal_title：Physics in medicine and biology

authors： Horas JA,Olguin OR,Rizzotto MG

更新日期：2005-04-21 00:00:00

abstract：:Low-strength anastomoses and thermal damage of tissue are major concerns in laser tissue welding techniques where laser energy is used to induce thermal changes in the molecular structure of the tissues being joined, hence allowing them to bond together. Laser tissue soldering, on the other hand, is a bonding techniqu...

journal_title：Physics in medicine and biology

authors： McNally KM,Sorg BS,Welch AJ,Dawes JM,Owen ER

更新日期：1999-04-01 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：: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：:Developments in positron emission tomography (PET) technology have resulted in systems with finer detector elements designed to further improve spatial resolution. However, there is a limit to what extent reducing detector element size will improve spatial resolution in PET. The spatial resolution of PET imaging is li...

journal_title：Physics in medicine and biology

authors： Levin CS,Hoffman EJ

更新日期：1999-03-01 00:00:00

abstract：:The dose distribution near a non-radioactive gold seed under a 6 MV photon beam was measured using radiographic film, water equivalent bolus and solid water slabs. This type of small seed is typically used as a marker in target positional verification using a portal imager for conformal prostate treatment such as inte...

journal_title：Physics in medicine and biology

authors： Chow JC,Grigorov GN

更新日期：2005-09-21 00:00:00

abstract：:The purpose of this research is to develop a 4DCBCT-based dose assessment method for calculating actual delivered dose for patients with significant respiratory motion or anatomical changes during the course of SBRT. To address the limitation of 4DCT-based dose assessment, we propose to calculate the delivered dose us...

journal_title：Physics in medicine and biology

authors： Cai W,Dhou S,Cifter F,Myronakis M,Hurwitz MH,Williams CL,Berbeco RI,Seco J,Lewis JH

更新日期：2016-01-21 00:00:00

abstract：:Computed tomography images have been acquired using an experimental (low atomic number (Z) insert) megavoltage cone-beam imaging system. These images have been compared with standard megavoltage and kilovoltage imaging systems. The experimental system requires a simple modification to the 4 MeV electron beam from an E...

journal_title：Physics in medicine and biology

authors： Roberts DA,Hansen VN,Thompson MG,Poludniowski G,Niven A,Seco J,Evans PM

更新日期：2011-07-21 00:00:00

abstract：:Patient motion is an important factor affecting the quality of external beam radiotherapy in breast patients. We analyse the motion of a dense set of surface points on breast patients throughout their treatment schedule to assess the magnitude and stability of motion, in particular, with respect to breast volume. We u...

journal_title：Physics in medicine and biology

authors： Price GJ,Sharrock PJ,Marchant TE,Parkhurst JM,Burton D,Jain P,Price P,Moore CJ

更新日期：2009-11-07 00:00:00

abstract：:Conventional molecular assessment of tissue through histology, if adapted to fresh thicker samples, has the potential to enhance cancer detection in surgical margins and monitoring of 3D cell culture molecular environments. However, in thicker samples, substantial background staining is common despite repeated rinsing...

journal_title：Physics in medicine and biology

authors： Xu X,Wang Y,Xiang J,Liu JTC,Tichauer KM

更新日期：2017-06-21 00:00:00