Assessment of new small-field detectors against standard-field detectors for practical stereotactic beam data acquisition.

abstract：:Digital phantoms continue to play a significant role in modeling and characterizing medical imaging. The currently available XCAT phantom incorporates both the flexibility of mathematical phantoms and the realistic nature of voxelized phantoms. This phantom generates images based on a regular breathing pattern and can...

journal_title：Physics in medicine and biology

authors： Mishra P,St James S,Segars WP,Berbeco RI,Lewis JH

更新日期：2012-06-07 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：:For treatments with dynamic intensity modulated radiotherapy (IMRT), the adjustment of multileaf collimator (MLC) parameters affecting both the optimization algorithm and dose distributions is crucial. The main parameters characterizing the MLC are the transmission (T) and the dosimetric leaf separation (DLS). The aim...

journal_title：Physics in medicine and biology

authors： Chauvet I,Petitfils A,Lehobey C,Kristner JY,Brunet Y,Lembrez R,Gaboriaud G,Mazal A,Zefkili S,Rosenwald JC

更新日期：2005-02-21 00:00:00

abstract：:In order to optimize external-beam conformal radiotherapy, patient movement during treatment must be minimized. For treatment on the upper torso, the target organs are known to move substantially due to patient respiration. This paper deals with the technical aspects of gating the radiotherapy beam synchronously with ...

journal_title：Physics in medicine and biology

authors： Kubo HD,Hill BC

更新日期：1996-01-01 00:00:00

abstract：:We have compared two methods of estimating the cellular radiosensitivity of a heterogeneous tumour, namely, via cell-survival and via tumour control probability (TCP) pseudo-experiments. It is assumed that there exists intra-tumour variability in radiosensitivity and that the tumour consists predominantly of radiosens...

journal_title：Physics in medicine and biology

authors： Stavrev P,Stavreva N,Ruggieri R,Nahum A

更新日期：2015-08-07 00:00:00

abstract：:Fluorescence diffuse optical tomography (fDOT) provides 3D images of fluorescence distributions in biological tissue, which represent molecular and cellular processes. The image reconstruction problem is highly ill-posed and requires regularisation techniques to stabilise and find meaningful solutions. Quadratic regul...

journal_title：Physics in medicine and biology

authors： Correia T,Koch M,Ale A,Ntziachristos V,Arridge S

更新日期：2016-02-21 00:00:00

abstract：:Breast MRI is frequently performed prior to breast conserving surgery in order to assess the location and extent of the lesion. Ideally, the surgeon should also be able to use the image information during surgery to guide the excision and this requires that the MR image is co-registered to conform to the patient's pos...

journal_title：Physics in medicine and biology

authors： Ebrahimi M,Siegler P,Modhafar A,Holloway CM,Plewes DB,Martel AL

更新日期：2014-04-07 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：:The standard Fourier metrics used for assessing image quality in computed tomography (CT) use a planar (2D) formulation of the noise equivalent quanta (NEQ) without a specific concept to manage the influence of longitudinal resolution variations, thus create a bias in the comparison of image quality for different reco...

journal_title：Physics in medicine and biology

authors： Monnin P,Viry A,Verdun FR,Racine D

更新日期：2020-06-09 00:00:00

abstract：:In this response we underscore that the instrumentation described in the original publication (Liu et al 2012 Phys. Med. Biol. 57 843-65) was based on pulse-sampling technique, while the comment by Zhang et al is based on the assumption that a time-correlated single photon counting (TCSPC) instrumentation was used. Th...

journal_title：Physics in medicine and biology

authors： Ma D,Liu J,Qi J,Marcu L

更新日期：2017-02-21 00:00:00

abstract：:Intensity modulated proton radiotherapy (IMPT) can reduce the dose to critical structures by optimizing the distribution and intensity of individual pencil beams. The IMPT can be delivered by dynamically scanning a pencil beam with variable intensity and energy across the tumor target volume. The lateral penumbra of a...

journal_title：Physics in medicine and biology

authors： Safai S,Bortfeld T,Engelsman M

更新日期：2008-03-21 00:00:00

abstract：:In the IAEA TRS-381 protocol, k(cel) and p(cel) account for the central electrode perturbation during the air kerma chamber calibration and the in-phantom measurements. The values of these correction factors are based mainly on Monte Carlo simulations. In the present work experimental data on k(cel) and p(cel) for the...

journal_title：Physics in medicine and biology

authors： Palm A,Mattsson O

更新日期：1999-05-01 00:00:00

abstract：:Most solid-state detectors, including 3D dosimeters, show lower signal in the Bragg peak than expected, a process termed quenching. The purpose of this study was to investigate how variation in chemical composition of a recently developed radiochromic, silicone-based 3D dosimeter influences the observed quenching in p...

journal_title：Physics in medicine and biology

authors： Høye EM,Skyt PS,Balling P,Muren LP,Taasti VT,Swakoń J,Mierzwińska G,Rydygier M,Bassler N,Petersen JB

更新日期：2017-02-21 00:00:00

abstract：:A comprehensive set of measurements and calculations has been conducted to investigate the accuracy of the Dose Planning Method (DPM) Monte Carlo code for electron beam dose calculations in heterogeneous media. Measurements were made using 10 MeV and 50 MeV minimally scattered, uncollimated electron beams from a racet...

journal_title：Physics in medicine and biology

authors： Chetty IJ,Moran JM,Nurushev TS,McShan DL,Fraass BA,Wilderman SJ,Bielajew AF

更新日期：2002-06-07 00:00:00

abstract：:The University of Washington (UW) Clinical Neutron Therapy System (CNTS) has been used to treat over 3300 patients. Treatment planning for these patients is currently performed using an MV x-ray model in Pinnacle® adapted to fit measurements of fast neutron output factors, wedge factors, depth-dose and lateral profile...

journal_title：Physics in medicine and biology

authors： Moffitt GB,Wootton LS,Hårdemark B,Sandison GA,Laramore GE,Parvathaneni U,Stewart RD

更新日期：2020-08-31 00:00:00

abstract：:In carbon-ion radiotherapy, single-beam delivery each day in alternate directions has been common practice for efficient operation, taking advantage of the Bragg peak and the relative biological effectiveness (RBE) for uniform dose conformation to a tumor. Treatments are usually fractionated and treatment plans are ev...

journal_title：Physics in medicine and biology

authors： Kanematsu N,Inaniwa T

更新日期：2017-02-07 00:00:00

abstract：:Correct classification of cystoscopy images depends on the interpreter's experience. Bladder cancer is a common lesion that can only be confirmed by biopsying the tissue, therefore, the automatic identification of tumors plays a significant role in early stage diagnosis and its accuracy. To our best knowledge, the use...

journal_title：Physics in medicine and biology

authors： Freitas NR,Vieira PM,Lima E,Lima CS

更新日期：2018-02-02 00:00:00

abstract：:This study evaluates the performance of the Bruker positron emission tomograph (PET) insert combined with a BioSpec 70/30 USR magnetic resonance imaging (MRI) scanner using the manufacturer acceptance protocol and the NEMA NU 4-2008 for small animal PET. The PET insert is made of 3 rings of 8 monolithic LYSO crystals ...

journal_title：Physics in medicine and biology

authors： Gsell W,Molinos C,Correcher C,Belderbos S,Wouters J,Junge S,Heidenreich M,Vande Velde G,Rezaei A,Nuyts J,Cawthorne C,Cleeren F,Nannan L,Deroose CM,Himmelreich U,González Martínez AJ

更新日期：2020-06-26 00:00:00

abstract：:This study investigated the temperature elevation in the eye of anatomically based human head models for plane-wave exposures. The finite-difference time-domain method is used for analyzing electromagnetic absorption and temperature elevation. The eyes in the anatomic models have average dimensions and weight. Computa...

journal_title：Physics in medicine and biology

authors： Hirata A,Watanabe S,Fujiwara O,Kojima M,Sasaki K,Shiozawa T

更新日期：2007-11-07 00:00:00

abstract：:Currently, standards for the compliance testing of wireless devices are being extended to cover a wider frequency band and different usage patterns of mobile phones as well as of novel body-worn and handheld devices. As a consequence, not only the head but also strongly varying tissue distributions of the body are exp...

journal_title：Physics in medicine and biology

authors： Christ A,Samaras T,Klingenböck A,Kuster N

更新日期：2006-10-07 00:00:00

abstract：:Accumulating evidence shows that hyperthermia improves head-and-neck cancer treatment. Over the last decade, we introduced a radiofrequency applicator, named HYPERcollar, which enables local heating also of deep locations in this region. Based on clinical experience, we redesigned the HYPERcollar for improved comfort,...

journal_title：Physics in medicine and biology

authors： Togni P,Rijnen Z,Numan WC,Verhaart RF,Bakker JF,van Rhoon GC,Paulides MM

更新日期：2013-09-07 00:00:00

abstract：:Ultrasound in the low megahertz frequency range is used by physiotherapists to treat a variety of conditions. The treatments reduce swelling, reduce pain and increase movement at joints. Ultrasound is now also beginning to be used to treat malignant tumours. The tumours are heated to temperatures between 42 degrees an...

journal_title：Physics in medicine and biology

authors： Quan KM,Shiran M,Watmough DJ

更新日期：1989-11-01 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：:The present note addresses the development of a lung tumor position predictor to be used in dynamic tumor tracking radiotherapy, abbreviated as DTT-RT. As there exists 50-500 ms positioning lag in the control of the multi-leaf collimator (MLC) of commercial medical linear accelerators, prediction of future lung tumor ...

journal_title：Physics in medicine and biology

authors： Jiang K,Fujii F,Shiinoki T

更新日期：2019-10-31 00:00:00

abstract：:The dosimetric measurement and modeling of small radiation treatment fields (<2 × 2 cm2) are difficult to perform and prone to error. Measurements of small fields are often adversely influenced by the properties of the detectors used to make them. The dosimetric properties of small fields have been difficult to accura...

journal_title：Physics in medicine and biology

authors： Hundertmark B,Sterpin E,Mackie T

更新日期：2011-06-21 00:00:00

abstract：:Rheumatoid arthritis is one of the most common epidemic diseases in the world. For some patients, the treatment with steroids or nonsteroidal anti-inflammatory drugs is not effective, thus necessitating physical removal of the inflamed synovium. Alternative approaches other than surgery will provide appropriate diseas...

journal_title：Physics in medicine and biology

authors： Wu J,Chang SJ,Chuang KS,Hsueh YW,Yeh KC,Wang JN,Tsai WP

更新日期：2007-03-21 00:00:00

abstract：:The purpose of this study was to improve the performance of a small gamma camera, utilizing a NaI(Tl) plate and a 5" position sensitive PMT. We attempted to build a NaI(Tl) plate crystal system which retained all its advantages, while at the same time integrating some of the advantages inherent in an array-type scinti...

journal_title：Physics in medicine and biology

authors： Jeong MH,Choi Y,Chung YH,Song TY,Jung JH,Hong KJ,Min BJ,Choe YS,Lee KH,Kim BT

更新日期：2004-11-07 00:00:00

abstract：:Respiratory gating can reduce the apparent respiratory motion during imaging and treatment; however, residual motion within the gating window remains. Respiratory training can improve respiratory reproducibility and, therefore, the efficacy of respiratory-gated radiotherapy. This study was conducted to determine wheth...

journal_title：Physics in medicine and biology

authors： George R,Ramakrishnan V,Siebers JV,Chung TD,Keall PJ

更新日期：2006-10-21 00:00:00

abstract：:The widely applied single-interaction analytic expression characterizing the energy resolution component of the angular resolution precision for an electronically collimated point source is extended to include multiple-interaction Compton scatter sequences as well as sequences terminated by photoelectric absorption. T...

journal_title：Physics in medicine and biology

authors： Durkee JW Jr,Antich PP,Tsyganov EN,Constantinescu A,Kulkarni PV,Smith BJ,Arbique GM,Lewis MA,Nguyen T,Raheja A,Thambi G,Parkey RW

更新日期：1998-10-01 00:00:00

abstract：:The design, construction and use of a large-scale field-cycled proton-electron double-resonance imaging (FC-PEDRI) imager is described. The imager is based on a whole-body sized, vertical field, 59 mT permanent magnet. Field cycling is accomplished by the field compensation method, and uses a secondary, resistive magn...

journal_title：Physics in medicine and biology

authors： Lurie DJ,Foster MA,Yeung D,Hutchison JM

更新日期：1998-07-01 00:00:00