Abstract:
:The possible use of fluorescence bronchoscopy for localization of bronchogenic tumours at the carcinoma in situ stage has been investigated. The target lesion is 80 micrometer thick with a mass of 250 microgram, containing 250 pg of haematoporphyrin derivative. The injected haematoporphyrin-derivative is preferentially taken up or retained by a malignant tumour, and can be detected in small amounts by its red flourescence under illumination by violet light. Previous clincial trials were successful in detecting tumours, but the instrumentation was only marginally adequate, the fluorescent compound was not standardized and no measurements or calculation of sensitivity were made. In this work, a fibreoptic bronchoscope system with a 200 W mercury vapour lamp, special violet-transmitting light conductor, sharp cut-off blue and red filters and three-stage image intensifier tube was designed and assembled. Measurements in vitro indicate the design objectives were met, and test on tumours are in progress.
journal_name
Phys Med Bioljournal_title
Physics in medicine and biologyauthors
Profio AE,Doiron DRdoi
10.1088/0031-9155/22/5/014subject
Has Abstractpub_date
1977-09-01 00:00:00pages
949-57issue
5eissn
0031-9155issn
1361-6560journal_volume
22pub_type
杂志文章abstract::The beam quality correction factor k Q for megavoltage photon beams has been calculated for eight PTW (Freiburg, Germany) ionization chambers (Farmer chambers PTW30010, PTW30011, PTW30012, and PTW30013, Semiflex 3D chambers PTW31021, PTW31010, and PTW31013, and the PinPoint 3D chamber PTW31016). Simulations performed ...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/1361-6560/ab9501
更新日期:2020-10-07 00:00:00
abstract::Imaging of the microvasculature is often performed using contrast agents in combination with either ultrasound (US) or magnetic resonance (MR) imaging. Contrast agents are used to enhance medical imaging by highlighting microvascular properties and function. Dynamic signal changes arising from the passage of contrast ...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/56/3/020
更新日期:2011-02-07 00:00:00
abstract::In brachytherapy, plans are routinely calculated using the AAPM TG43 formalism which considers the patient as a simple water object. An accurate modeling of the physical processes considering patient heterogeneity using Monte Carlo simulation (MCS) methods is currently too time-consuming and computationally demanding ...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/60/13/4987
更新日期:2015-07-07 00:00:00
abstract::To evaluate the effect of approximations in clinical analytical calculations performed by a treatment planning system (TPS) on dosimetric indices in intensity modulated proton therapy. TPS calculated dose distributions were compared with dose distributions as estimated by Monte Carlo (MC) simulations, calculated with ...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/1361-6560/aaa845
更新日期:2018-02-09 00:00:00
abstract::The application of thermal modelling for hyperthermia and thermal ablation is severely hampered by lack of information about perfusion and vasculature. However, recently, with the advent of sophisticated angiography and dynamic contrast enhanced (DCE) imaging techniques, it has become possible to image small vessels a...
journal_title:Physics in medicine and biology
pub_type: 临床试验,杂志文章
doi:10.1088/0031-9155/51/4/004
更新日期:2006-02-21 00:00:00
abstract::Ankylosing spondylitis is a disease characterized by abnormal bone formation (syndesmophyte) at the margins of inter-vertebral disc spaces. Syndesmophyte growth is currently typically monitored by the visual inspection of radiographs. The limitations inherent to the modality (2D projection of a 3D object) and rater (q...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/57/14/4683
更新日期:2012-07-21 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
pub_type: 杂志文章
doi:10.1088/0031-9155/34/11/019
更新日期:1989-11-01 00:00:00
abstract::Techniques for reducing computation time in 3D photon dose calculations are addressed with specific emphasis given to the convolution/superposition approach. A single polyenergetic superposition model calculating absorbed dose per incident photon fluence (Gy cm2) was developed in terms of TERMA and a total energy depo...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/42/8/001
更新日期:1997-08-01 00:00:00
abstract::The scope of this work was to develop a synthetic single crystal diamond dosimeter (SCDD-Pro) for accurate relative dose measurements of clinical proton beams in water. Monte Carlo simulations were carried out based on the MCNPX code in order to investigate and reduce the dose curve perturbation caused by the SCDD-Pro...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/1361-6560/aa70cf
更新日期:2017-07-07 00:00:00
abstract::The values of the replacement correction factors (P(repl), or in the IAEA's notation p(dis)p(cav)) used for cylindrical chambers in high-energy photon beams represent one of the most significant differences between the AAPM and the IAEA dosimetry protocols. In a previous study (Wang L L W and Rogers D W O 2008 Med. Ph...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/54/6/014
更新日期:2009-03-21 00:00:00
abstract::Microcalcification is one of the earliest and main indicators of breast cancer. Because dual-energy digital mammography could suppress the contrast between the adipose and glandular tissues of the breast, it is considered a promising technique that will improve the detection of microcalcification. In dual-energy digit...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/53/22/004
更新日期:2008-11-21 00:00:00
abstract::Magnetic resonance and ultrasound elastography techniques are now important tools for staging high-grade fibrosis in patients with chronic liver disease. However, uncertainty remains about the effects of simple accumulation of fat (steatosis) and inflammation (steatohepatitis) on the parameters that can be measured us...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/1361-6560/aac09a
更新日期:2018-05-17 00:00:00
abstract::Previously, readings of air-filled ionization chambers have been described as being influenced by magnetic fields. To use these chambers for dosimetry in magnetic resonance guided radiotherapy (MRgRT), this effect must be taken into account by introducing a correction factor k B. The purpose of this study is to system...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/1361-6560/aac4f2
更新日期:2018-06-07 00:00:00
abstract::The in vivo electric conductivity (σ) values of tissue are essential for accurate electromagnetic simulations and specific absorption rate (SAR) assessment for applications such as thermal dose computations in hyperthermia. Currently used σ-values are mostly based on ex vivo measurements. In this study the conductivit...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/61/4/1596
更新日期:2016-02-21 00:00:00
abstract::The purpose of this work was to characterize expert variation in segmentation of intracranial structures pertinent to radiation therapy, and to assess a registration-driven atlas-based segmentation algorithm in that context. Eight experts were recruited to segment the brainstem, optic chiasm, optic nerves, and eyes, o...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/56/14/021
更新日期:2011-07-21 00:00:00
abstract::Iterative tomographic reconstruction has been established as a viable alternative for data analysis in phase-sensitive x-ray imaging based on the edge-illumination principle. However, previously published approaches did not account for drifts of optical elements during a scan, which can lead to artefacts. Up to now, t...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/1361-6560/ab439d
更新日期:2019-10-10 00:00:00
abstract::The architecture of multi-layer imagers (MLIs) can be exploited to provide megavoltage spectral imaging (MVSPI) for specific imaging tasks. In the current work, we investigated bone suppression and gold fiducial contrast enhancement as two clinical tasks which could be improved with spectral imaging. A method based on...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/1361-6560/aabe21
更新日期:2018-05-10 00:00:00
abstract::At the UMC Utrecht a prototype MR-linac has been installed. The system consists of an 8 MV Elekta linear accelerator and a 1.5 T Philips MRI system. This paper investigates the performance of the IC PROFILER™, a multi-axis ionization chamber array, in a 1.5 T magnetic field. The influence of the magnetic field on the ...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/59/7/1845
更新日期:2014-04-07 00:00:00
abstract::The optical properties (absorption and scattering coefficients and the scattering anisotropy factor) were measured in vitro for cartilage, liver, lung, muscle, myocardium, skin, and tumour (colon adenocarcinoma CC 531) at 630, 632.8, 790, 850 and 1064 nm. Rabbits, rats, piglets, goats, and dogs were used to obtain the...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/42/11/017
更新日期:1997-11-01 00:00:00
abstract::For proton therapy, an accurate conversion of CT HU to relative stopping power (RSP) is essential. Validation of the conversion based on real tissue samples is more direct than the current practice solely based on tissue substitutes and can potentially address variations over the population. Based on a novel dose exti...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/1361-6560/aa782c
更新日期:2017-06-23 00:00:00
abstract::Quantifying the retention or washout of (99m)Tc-Sestamibi (MIBI) in breast tumours in vivo may provide a basis for predicting the chemotherapy response. The aim of this study is to investigate the variations and limitations of the different methods used to quantify these parameters. A phantom was developed that allowe...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/50/9/013
更新日期:2005-05-07 00:00:00
abstract::Numerous studies of early-stage breast cancer treated with breast conserving surgery (BCS) and radiotherapy (RT) have been published in recent years. Both external beam radiotherapy (EBRT) and/or brachytherapy (BT) with different fractionation schemes are currently used. The present RT practice is largely based on emp...
journal_title:Physics in medicine and biology
pub_type: 杂志文章,meta分析
doi:10.1088/0031-9155/48/20/004
更新日期:2003-10-21 00:00:00
abstract::This paper discusses the effect of blood perfusion on the ablation of rat liver tissue with high-intensity focused ultrasound (HIFU). For this study a practical method has been developed, in which the liver blood flow can be reduced by ligation of the hepatic artery and portal vein. During the treatment the rat liver ...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/38/11/011
更新日期:1993-11-01 00:00:00
abstract::For renal dynamic studies, the COST B2 hybrid phantom is an example of an artificially created software phantom. Although this phantom is useful, it is not possible to implement the phantom in a self-consistent fashion to produce, for example, a collection of tracer in the bladder which is related to the flow from the...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/44/2/008
更新日期:1999-02-01 00:00:00
abstract::We implemented a hybrid scatter-correction method for 3D PET that combines two scatter-correction methods in a complementary way. The implemented scheme uses a method based on the discrimination of the energy of events (the estimation of trues method (ETM)) and an auxiliary method (the single scatter simulation method...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/47/9/310
更新日期:2002-05-07 00:00:00
abstract::This paper investigates the feasibility of a scanned cylindrical ultrasound system for producing uniform heating from the central to the superficial portions of the breast or localized heating within the breast at a specific location. The proposed system consists of plane ultrasound transducer(s) mounted on a scanned ...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/51/3/005
更新日期:2006-02-07 00:00:00
abstract::By the end of 2002, 33 398 patients worldwide had been treated with proton radiotherapy, 10 829 for eye diseases. The dose prediction algorithms used today for ocular proton therapy treatment planning rely on parameterizations of measured proton dose distributions, i.e., broad-beam and pencil-beam techniques, whose pr...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/50/22/002
更新日期:2005-11-21 00:00:00
abstract::A new function to treat tetrahedral-mesh geometry was implemented in the particle and heavy ion transport code systems. To accelerate the computational speed in the transport process, an original algorithm was introduced to initially prepare decomposition maps for the container box of the tetrahedral-mesh geometry. Th...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/1361-6560/aa6b45
更新日期:2017-06-21 00:00:00
abstract::Deformable image registration is widely used in various radiation therapy applications including daily treatment planning adaptation to map planned tissue or dose to changing anatomy. In this work, a simple and efficient inverse consistency deformable registration method is proposed with aims of higher registration ac...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/53/21/017
更新日期:2008-11-07 00:00:00
abstract::Many applications of electroporation, especially those utilizing electrofusion and in-vivo electroporation, involve cell environments that include close cell-to-cell proximity and a wide range of target cell size. It is important to understand how this kind of environment may alter optimum electroporation electrical p...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/51/12/012
更新日期:2006-06-21 00:00:00