Abstract:
:We have developed and tested an MR-compatible gamma probe to simultaneously obtain anatomical information and functional information during surgery. The probe consists of a probe head, an optical fibre bundle and a photo-multiplier tube (PMT). The NaI(T1) scintillator contained in the probe head is connected to a 7 m optical fibre bundle that transfers the scintillation photons produced in the NaI(T1) to an area of low magnetic field or out of the MR-scanner's magnetic shielded room. Although the light loss due to the optical fibre bundle was more than 90%, the photo-peak of the gamma for Co-57 (122 keV) could be observed. The point spread function was 4.5 mm full width at half maximum (FWHM) at 5 mm from the collimator surface for 122 keV gamma photons. Furthermore, there was no sensitivity change outside the MR-scanner, inside the MR-scanner without scanning and inside the MR-scanner with scanning. The probe produced a small artefact on the phantom image of the MR-scanner due to the susceptibility difference of the alloy used for the collimator and the shield. However, the artefact was only limited to area surrounding the probe. These results indicate that the developed MR-compatible gamma probe will make it possible to realize the combined MR/RI guided surgery that provides surgeons with anatomical and RI distribution information simultaneously.
journal_name
Phys Med Bioljournal_title
Physics in medicine and biologyauthors
Yamamoto S,Kuroda K,Senda Mdoi
10.1088/0031-9155/49/15/005subject
Has Abstractpub_date
2004-08-07 00:00:00pages
3379-88issue
15eissn
0031-9155issn
1361-6560journal_volume
49pub_type
杂志文章abstract::The derivative at constant direction is frequently used in inversion of cone-beam data. Several algorithms for computing the derivative have been proposed in the literature. The best algorithm to date has been proposed recently by Noo et al (2007 Phys. Med. Biol. 52 5393-414). In this note we propose a new, simple and...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/56/4/N01
更新日期:2011-02-21 00:00:00
abstract::A method of computing theoretical X-ray spectra in the range 30-150 kV is presented. The theoretical spectra are compared with constant potential, high resolution spectra from a tungsten target measured with a Ge(Li) detector, for a range of target angles, tube voltage and filtrations. Above 100 kV the spectra were al...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/24/3/002
更新日期:1979-05-01 00:00:00
abstract::Numerous studies have reported the measurements of the dielectric properties of the skin. Clarifying the manner in which the human body interacts with electromagnetic waves is essential for medical research and development, as well as for the safety assessment of electromagnetic wave exposure. The skin comprises sever...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/59/16/4739
更新日期:2014-08-21 00:00:00
abstract::A cost-effective method employing polysulphone, nalidixic acid, 8-methoxypsoralen and phenothiazine as UV dosimeters is presented for evaluating the UV spectrum. The exposure measured by each dosimeter is a function of the source spectrum and the spectral response of the material. Each material has a different spectra...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/42/1/005
更新日期:1997-01-01 00:00:00
abstract::A software program, SpekCalc, is presented for the calculation of x-ray spectra from tungsten anode x-ray tubes. SpekCalc was designed primarily for use in a medical physics context, for both research and education purposes, but may also be of interest to those working with x-ray tubes in industry. Noteworthy is the p...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/54/19/N01
更新日期:2009-10-07 00:00:00
abstract::Recent acute shortage of medical radioisotopes prompted investigations into alternative methods of production and the use of a cyclotron and ¹⁰⁰Mo(p,2n)(99m)Tc reaction has been considered. In this context, the production yields of (99m)Tc and various other radioactive and stable isotopes which will be created in the ...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/56/17/002
更新日期:2011-09-07 00:00:00
abstract::Measurement of the dielectric properties of ocular tissues up to 110 GHz was performed by the coaxial probe method. A coaxial sensor was fabricated to allow the measurement of small amounts of biological tissues. Four-standard calibration was applied in the dielectric property measurement to obtain more accurate data ...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/60/16/6273
更新日期:2015-08-21 00:00:00
abstract::We have developed an x-ray imaging system for in vivo four-dimensional computed tomography (4DCT) of small animals for pre-clinical lung investigations. Our customized laboratory facility is capable of high resolution in vivo imaging at high frame rates. Characterization using phantoms demonstrate a spatial resolution...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/1361-6560/aab8d2
更新日期:2018-04-20 00:00:00
abstract::The purpose of this study is to evaluate a new method to improve performance of computer-aided detection (CAD) schemes of screening mammograms with two approaches. In the first approach, we developed a new case based CAD scheme using a set of optimally selected global mammographic density, texture, spiculation, and st...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/1361-6560/aa5081
更新日期:2017-01-21 00:00:00
abstract::The theory of task-based assessment of image quality is reviewed in the context of imaging with ionizing radiation, and objective figures of merit (FOMs) for image quality are summarized. The variation of the FOMs with the task, the observer and especially with the mean number of photons recorded in the image is discu...
journal_title:Physics in medicine and biology
pub_type: 杂志文章,评审
doi:10.1088/0031-9155/60/2/R1
更新日期:2015-01-21 00:00:00
abstract::A 3D anatomical computational model is developed to assess thermal effects due to exposure to the electromagnetic field required to power a new investigational active implantable microvalve for the treatment of glaucoma. Such a device, located in the temporal superior eye quadrant, produces a filtering bleb, which is ...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/1361-6560/aa5dae
更新日期:2017-05-07 00:00:00
abstract::Calculations indicate that an assembly consisting of an antimony-beryllium source at the centre of a 4 cm radius water sphere surrounded by a 1 mm thick shell of boron-10 will emit neutrons with a broad spectrum at intermediate energies. A device based on this design was constructed using a water-filled, boron-carbide...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/21/1/007
更新日期:1976-01-01 00:00:00
abstract::Diffusion weighted magnetic resonance imaging offers a non-invasive tool to explore the three-dimensional structure of brain white matter in clinical practice. Anisotropic diffusion hardware phantoms are useful for the quantitative validation of this technique. This study provides guidelines on how to manufacture anis...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/53/19/009
更新日期:2008-10-07 00:00:00
abstract::A new component module (CM), designated DYNVMLC, was developed to fully model the geometry of the Varian Millennium 120 leaf collimator using the BEAMnrc Monte Carlo code. The model includes details such as the leaf driving screw hole, support railing groove and leaf tips. Further modifications also allow sampling of ...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/48/24/004
更新日期:2003-12-21 00:00:00
abstract::Quantification in cardiac mouse positron emission tomography (PET) imaging is limited by the imaging spatial resolution. Spillover of left ventricle (LV) myocardial activity into adjacent organs results in partial volume (PV) losses leading to underestimation of myocardial activity. A PV correction method was develope...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/57/13/4309
更新日期:2012-07-07 00:00:00
abstract::In this paper, we investigate an off-line strategy to incorporate inter-fraction organ motion in IMRT treatment planning. It was suggested that inverse planning could be based on a probability distribution of patient geometries instead of a single snap shot. However, this concept is connected to two intrinsic problems...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/49/17/013
更新日期:2004-09-07 00:00:00
abstract::Although field area and object thickness are important parameters in comparisons of techniques for optimal reduction of scattered radiation to the image, they are in practice seldom varied. For this reason, we suggest that contrast degradation (CDF) and contrast improvement (CIF) factors be more frequently used and ap...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/31/7/004
更新日期:1986-07-01 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
pub_type: 杂志文章
doi:10.1088/1361-6560/aba7d1
更新日期:2020-07-21 00:00:00
abstract::Permanent in vivo verification of IMRT photon beam profiles by a radiation detector with spatial resolution, positioned on the radiation entrance side of the patient, has not been clinically available so far. In this work we present the DAVID system, which is able to perform this quality assurance measurement while th...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/51/5/013
更新日期:2006-03-07 00:00:00
abstract::A technique is described for examining the mode of operation of radiation detectors and estimating the losses and gains caused by random summing effects in spectra acquired at high counting rates. The technique is applied to estimating the errors caused by random summing when measuring the amounts of carbon and nitrog...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/34/8/010
更新日期:1989-08-01 00:00:00
abstract::A novel radiation targeted therapy is investigated for HER-2 positive breast cancers. The proposed concept combines two known approaches, but never used together for the treatment of advanced, relapsed or metastasized HER-2 positive breast cancers. The proposed radiation binary targeted concept is based on the anti HE...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/51/6/001
更新日期:2006-03-21 00:00:00
abstract::We propose and evaluate the performance of an improved preclinical positron emission tomography (PET) scanner design, referred to as Polaroid-PET, consisting of a detector equipped with a layer of horizontal Polaroid to filter scintillation photons with vertical polarization. This makes it possible to improve the spat...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/1361-6560/abaeb8
更新日期:2020-12-02 00:00:00
abstract::Monte Carlo simulation was used to calculate correction factors for output factor (OF), percentage depth-dose (PDD), and off-axis ratio (OAR) measurements with the CyberKnife M6 System. These include the first such data for the InCise MLC. Simulated detectors include diodes, air-filled microchambers, a synthetic micro...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/1361-6560/aa5610
更新日期:2017-02-07 00:00:00
abstract::In this work we present a new 3D numerical model for heat transfer in the human eye, which takes into account the aqueous humour flow in the anterior chamber. We show that consideration of this phenomenon in the calculations alters the temperature distribution on the corneal and lens surfaces, without, however, notice...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/55/19/003
更新日期:2010-10-07 00:00:00
abstract::The biological mechanisms of platelet destruction must be correctly identified before platelet survival curves can be interpreted. This report develops a theory of platelet destruction which is compared with experiments performed on platelets labelled with the radioactive isotope 51Cr. Platelet destruction rate is a c...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/28/12/001
更新日期:1983-12-01 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
pub_type: 杂志文章
doi:10.1088/0031-9155/44/10/305
更新日期:1999-10-01 00:00:00
abstract::Crucial to all cancer therapy modalities is a strong correlation between treatment and effect. Predictability of therapy success/failure allows for the optimization of treatment protocol and aids in the decision of whether additional treatment is necessary to prevent tumour progression. This work evaluated the relatio...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/56/17/016
更新日期:2011-09-07 00:00:00
abstract::Average penetration depths and detour factors of 1-50 MeV electrons in water and plastic materials have been computed by means of analytical calculation, within the continuous-slowing-down approximation and including multiple scattering, and using the Monte Carlo codes ITS and PENELOPE. Results are compared to detour ...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/41/7/004
更新日期:1996-07-01 00:00:00
abstract::Both inhomogeneity in the main magnetic field and non-linearity in the gradient fields introduce errors in NMR images reconstructed from projections. It is found that the image artefacts caused by these two sources are separable. The inhomogeneous main field blurs the image while the nonlinear gradients distort the im...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/28/8/005
更新日期:1983-08-01 00:00:00
abstract::Intravascular coronary thermography is a method that may detect vulnerable, atherosclerotic plaques and is currently evaluated in a clinical setting. Active macrophages or enzymatic heat releasing processes in vulnerable plaques may act as heat sources. To better understand the parameters of influence on thermographic...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/49/19/001
更新日期:2004-10-07 00:00:00