Abstract：
:X-ray imaging of the chest is challenging because of the large differences in x-ray attenuation between the mediastinal and lung regions of the chest. This large dynamic range of chest exit exposure, along with associated large changes in the scatter component of the beam, makes film based chest imaging difficult to optimise in terms of image contrast and image receiver latitude. Chest radiographic contrast has been studied in terms of intensifying screen luminance differences, as a function of kVp and scatter rejection. An anatomical model has been derived from CT studies and includes simulation of typical lung, retrocardiac and mediastinal regions with the contrast medium of a 5 mm water equivalent mass. Information has also been obtained on the range of luminance generated in the receptor between the three regions. Comparative patient doses have also been calculated. The computer model consists of analytical algorithms, beginning with the primary spectra generated after the method of Birch and Marshall. The generation of secondary radiation is achieved by an algorithm that parameterises published Monte Carlo data. Grid transmission is calculated for both primary and secondary radiation. The energy absorbed in the screen is calculated to include the absorption of K-characteristic radiation. Simulation of energies from 60-120 kVp with a variety of grids (including no grid) showed that contrast, in all areas of the chest radiograph, was a weak function of kVp and a strong function of scatter rejection. This was most evident in thicker regions such as the mediastinum.(ABSTRACT TRUNCATED AT 250 WORDS)
journal_name
Australas Phys Eng Sci Medjournal_title
Australasian physical & engineering sciences in medicineauthors
McLean Dsubject
Has Abstractpub_date
1993-12-01 00:00:00pages
179-85issue
4eissn
0158-9938issn
1879-5447journal_volume
16pub_type
杂志文章abstract：:The accuracy of a computed tomography (CT)-relative electron density (RED) curve may have an indirect impact on the accuracy of dose calculation by a treatment planning system (TPS). This effect has not been previously quantified for input of different CT-RED curves from different CT-scan units in the Monaco TPS. This...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章
doi：10.1007/s13246-019-00745-6
更新日期：2019-06-01 00:00:00
abstract：:Diamond detectors are particularly well suited for dosimetry applications in radiotherapy for reasons including near-tissue equivalence and high-spatial resolution resulting from small sensitive volumes. However, these detectors have not become commonplace due to high cost and poor availability arising from the need f...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章
doi：10.1007/s13246-010-0040-6
更新日期：2010-12-01 00:00:00
abstract：:Monte Carlo modelling of particle transport problems in medical radiation physics offers significant advantages over other techniques. Experiments can be performed without having to set up the physical situation, and "impossible" experiments can be performed, such as labelling multiple-scattered particles or simulatin...
journal_title：Australasian physical & engineering sciences in medicine
pub_type：
doi：
更新日期：1990-09-01 00:00:00
abstract：:Rats are often used in the electromagnetic field (EMF) exposure experiments. In the study for the effect of 900 MHz EMF exposure on learning and memory in SD rats, the specific absorption rate (SAR) and the temperature rise in the rat head are numerically evaluated. The digital anatomical model of a SD rat is reconstr...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章
doi：10.1007/s13246-013-0202-4
更新日期：2013-06-01 00:00:00
abstract：:Properties of a new polymer gel with cross-linked polyvinyl alcohol as a gelatinous matrix were investigated. The new polymer gel dosimeter was named PVABAT. The irradiation was performed using a calibrated 60Co beam. The dose responses of the PVABAT formulations were quantified with MRI transverse relaxation rate (R2...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章
doi：10.1007/s13246-017-0573-z
更新日期：2017-09-01 00:00:00
abstract：:A simple and rapid technique to measure the proton beam energy in the external beam line of a medical cyclotron has been examined. A stack of 0.1 mm thick high purity copper (Cu) foils was bombarded and the relative activity of 65Zn produced in each foil was compared to a computational model that predicted activity, b...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章
doi：10.1007/BF03178634
更新日期：2009-06-01 00:00:00
abstract：:Electrocardiogram (ECG) signal gives a lot of information on the physiology of heart. In reality, noise from various sources interfere with the ECG signal. To get the correct information on physiology of the heart, noise cancellation of the ECG signal is required. In this paper, the effectiveness of extended Kalman sm...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章
doi：10.1007/s13246-016-0468-4
更新日期：2016-09-01 00:00:00
abstract：:TomoTherapy can provide highly accurate SABR deliveries, but currently it does not have any effective motion management techniques. Shallow breathing has been identified as one possible motion management solution on TomoTherapy, which has been made possible with the BreatheWell audiovisual biofeedback (AVB) device. Si...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章
doi：10.1007/s13246-019-00727-8
更新日期：2019-03-01 00:00:00
abstract：:Numerical simulation is performed to demonstrate that hemodynamic factors are significant determinants for the development of a vascular pathology. Experimental measurements by particle image velocimetry are carried out to validate the credibility of the computational approach. We present a study for determining compl...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章
doi：10.1007/s13246-010-0050-4
更新日期：2010-12-01 00:00:00
abstract：:This study was aimed to improve the surgical accuracy of plating and screwing for complicated tibial plateau fracture assisted by 3D implants library and 3D-printed navigational template. Clinical cases were performed whereby complicated tibial plateau fractures were imaged using computed tomography and reconstructed ...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章
doi：10.1007/s13246-015-0330-0
更新日期：2015-03-01 00:00:00
abstract：:Rotary blood pumps have the potential to become a viable long-term treatment option for the heart failure patients to bridge to transplantation or destination therapy. However, these devices operate at a constant speed which may lead to long term complications or they may operate in an undesired support mode such as e...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章,评审
doi：10.1007/s13246-015-0405-y
更新日期：2016-03-01 00:00:00
abstract：:A electrocardiogram (ECG) central station has been developed for the Intensive Care Unit at Christchurch Hospital. The system allows the selection and display of four ECGs selected from seven bedside monitors in the Unit. It also provides for automatic display, hard copy and audio alarm of ECG from any monitor which h...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章
doi：
更新日期：1990-03-01 00:00:00
abstract：:Lymphocyte recirculation between lymphatic and blood vessels and migration through tissues are essential mechanisms underlying immunological surveillance. However, the kinetics of lymphocyte migration through lymphoid tissues remains poorly understood. The present study of lymphocyte migration, based on a sheep model ...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章
doi：10.1007/BF03178774
更新日期：2002-09-01 00:00:00
abstract：:The dosimetric features of the Fricke dosimeter in clinical linear accelerator beams are considered. Experimental data were obtained using various nominal energies 6 and 18 MV, 12 and 15 MeV, including the (60)Co γ-ray beam. The calibration of the dosimeters was performed using the ionization chamber as a reference do...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章
doi：10.1007/s13246-011-0093-1
更新日期：2011-12-01 00:00:00
abstract：:Postural balance requires using joint strategies which may be changed from normal conditions by interfering with the sensory information. The goal of the present study was to quantitatively evaluate the role of the joint mechanisms during perturbed stance. Visual and cognitive interference was imposed to sixteen healt...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章
doi：10.1007/s13246-017-0606-7
更新日期：2018-03-01 00:00:00
abstract：:A variable magnetic deflector which attaches onto the treatment head of a linear accelerator has reduced skin dose by as much as 65% for 6MV x-rays. The magnetic deflector is constructed from Neodymium Iron Boron (NdFeB) rare earth magnets. It weighs approximately 15 kg and is designed to easily fit onto the accessory...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章
doi：
更新日期：1997-06-01 00:00:00
abstract：:The reference air kerma rate from 192Ir High Dose Rate (HDR) brachytherapy sources can be measured using a suitably calibrated Farmer chamber and an appropriate in-air calibration jig. When a primary standard for 192Ir gamma rays is available, a calibration coefficient for the chamber and jig combination can be determ...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章
doi：10.1007/BF03178603
更新日期：2008-12-01 00:00:00
abstract：:Radiofrequency-electromagnetic field (RF-EMF) exposure of human populations is increasing due to the widespread use of mobile phones and other telecommunication and broadcasting technologies. There are ongoing concerns about potential short- and long-term public health consequences from RF-EMF exposures. To elucidate ...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章,评审
doi：10.1007/s13246-015-0412-z
更新日期：2016-03-01 00:00:00
abstract：:The knowledge of radiation dose at all points of interest within a patient's body is essential for the evaluation of treatment plans and for the judicious selection of the best one from among a set of competing plans. This paper discusses the physical and geometric aspects of radiation dose distribution calculations n...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章
doi：
更新日期：1989-12-01 00:00:00
abstract：:Over 90% of craniopharyngeal brain tumors are cystic, which enables the injection of beta emitters such as phosphorus-32 (32P) radio-colloid into cysts for their treatment. The aim of this study was to evaluate the clinical and theoretical modelling of Bremsstrahlung radiation dose resulting from stereotactic radio-co...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章
doi：10.1007/s13246-018-0665-4
更新日期：2018-09-01 00:00:00
abstract：:It was the aim of this work to assess and track the workload, working conditions and professional recognition of radiation oncology medical physicists (ROMPs) in the Asia Pacific region over time. In this third survey since 2008, a structured questionnaire was mailed in 2014 to 22 senior medical physicists representin...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章
doi：10.1007/s13246-015-0373-2
更新日期：2015-09-01 00:00:00
abstract：:Coronary artery disease producing ischemic cardiomyopathy is the most frequent cause of left ventricular systolic dysfunction. Non-ischemic cardiomyopathies can also produce systolic dysfunction; they may be inherited as genetic disorders or occur sporadically. These coronary injuries have repercussions on the left ve...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章
doi：10.1007/BF03178864
更新日期：2005-03-01 00:00:00
abstract：:The purpose of this study was to measure skin dose using radiochromic film for two step-and-shoot IMRT fields and compare the results to the skin dose for a conventional open field. All exposures were made using a 6 MV photon beam produced by a Varian 21EX linear accelerator (Varian Medical Systems, CA, USA) equipped ...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章
doi：10.1007/BF03178577
更新日期：2006-09-01 00:00:00
abstract：:The effects of internal and external scatter on surface, build-up and depth dose characteristics simulated by Monte Carlo code EGSnrc for varying field size and SSD for a 10 MeV monoenergetic electron beam with and without an accelerator model are extensively studied in this paper. In particular, sub-millimetre surfac...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章
doi：10.1007/BF03178710
更新日期：2005-09-01 00:00:00
abstract：:Linear scaling is used to convert raw computed tomography (CT) pixel values into Hounsfield units corresponding to different tissue values. Analysis of a benchmarking study, presented here, where the same CT scan was imported into and then exported from multiple radiotherapy treatment planning systems, found inconsist...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章
doi：10.1007/s13246-018-0651-x
更新日期：2018-09-01 00:00:00
abstract：:A 69 year old male was treated with an ablative dose of 3.7 GBq (100 mCi) of I131 for carcinoma of the thyroid and died 10 days after administration. The requirement for an autopsy and the level of radiation still present in the body necessitated the intervention of Radiation Safety Personnel to minimise support staff...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章
doi：
更新日期：1991-06-01 00:00:00
abstract：:The effect of radiation in regard to breast carcinogenesis is well studied and analysed from data from atomic bomb survivors, patients treated for acute mastitis and tuberculosis patients monitored by fluoroscopy. Therefore the radiation received by the untreated breast during breast irradiation of the other breast, i...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章
doi：10.1007/BF03178353
更新日期：2001-06-01 00:00:00
abstract：:At present, the Australasian College of Physical Scientists and Engineers in Medicine does not support the practice of self-referred whole-body CT screening of asymptomatic patients because: The procedure involves a non-trivial radiation dose, which assumes even greater significance in the context of an ongoing screen...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 指南,杂志文章
doi：10.1007/BF03178880
更新日期：2004-03-01 00:00:00
abstract：:Wavelet theory is emerging as one of the prevalent tool in signal and image processing applications. However, the most suitable mother wavelet for these applications is still a relative question mark amongst researchers. Selection of best mother wavelet through parameterization leads to better findings for the analysi...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章
doi：10.1007/s13246-014-0264-y
更新日期：2014-06-01 00:00:00
abstract：:Surface, build-up and depth dose characteristics of a monoenergetic electron point source simulated by Monte Carlo code MCNP4c for varying field size and SSD are extensively studied in this paper. MCNP4c (Monte Carlo N-Particle Transport Code System) has been extensively used in clinical dose simulation for its versat...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章
doi：10.1007/BF03178652
更新日期：2004-12-01 00:00:00
