Abstract：
:Three different air channels were constructed in solid water. These resemble upper respiratory and larynx geometry. Central-axis depth-dose distributions were measured on and beyond the distal surface of the air cavities. The measurements were made with a parallel-plate Markus ionisation chamber and TLDs for 6 and 25 MV X-ray beams of field sizes 4 cm x 4 cm and 4 cm x 7 cm. Measured dose was then compared to calculated dose for the Clarkson Scatter Integration and Equivalent Tissue-air Ratio (ETAR) algorithms. Both algorithms show errors in dose calculation at the distal surface of air cavities mainly because they fail to account for the effect of electronic disequilibrium. The magnitude of prediction error is found to depend on energy, field size and cavity geometry. For a 4 cm x 4 cm field at 6 MV the dose difference between the calculated value and the measured value, at the distal surface of square cavity is 8.2% and 13.7% for the ETAR and Clarkson algorithm respectively while that for a 4 cm x 7 cm field, the dose difference is reduced to 1.4% and 7.1% respectively. In general the ETAR algorithm shows better performance than the Clarkson algorithm because the Clarkson method calculates scatter dose assuming a homogeneous water medium while the ETAR uses a weighted sum of scatter components which is density dependent. The measured data can be used as benchmark data in the development and testing of new photon dose calculation algorithms.
journal_name
Australas Phys Eng Sci Medjournal_title
Australasian physical & engineering sciences in medicineauthors
Wong TP,Kan WK,Law Msubject
Has Abstractpub_date
1996-12-01 00:00:00pages
237-47issue
4eissn
0158-9938issn
1879-5447journal_volume
19pub_type
杂志文章abstract：:This paper proposes a novel approach to detect epilepsy seizures by using Electroencephalography (EEG), which is one of the most common methods for the diagnosis of epilepsy, based on 1-Dimension Local Binary Pattern (1D-LBP) and grey relational analysis (GRA) methods. The main aim of this paper is to evaluate and val...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章
doi：10.1007/s13246-015-0362-5
更新日期：2015-09-01 00:00:00
abstract：:A solid water breast phantom with a lung equivalent material was constructed to investigate interface effects of 6 MV tangential photon fields. The phantom was built so that Thermo-luminescence Dosimeters (TLD) could be used for comparison to a pencil beam and Equivalent Tissue-Air-Ratio (ETAR) algorithms. The investi...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章
doi：
更新日期：1998-03-01 00:00:00
abstract：:An automated computer-aided diagnosis system is developed to classify benign and malignant thyroid nodules using multi-stained fine needle aspiration biopsy (FNAB) cytological images. In the first phase, the image segmentation is performed to remove the background staining information and retain the appropriate foregr...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章
doi：10.1007/s13246-013-0199-8
更新日期：2013-06-01 00:00:00
abstract：:Post installation acceptance testing is vital to demonstrate that the equipment meets the vendor's specification and is suitable for clinical studies. The test procedures described in the NEMA NU 2-2001 document form the basis of vendor performance specifications of PET scanners and hence are also appropriate for acce...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章
doi：10.1007/s13246-010-0016-6
更新日期：2010-06-01 00:00:00
abstract：:A new era has arrived for the Biomedical Engineering Department at the Royal Women's Hospital in Melbourne. We have developed a system to qualitatively test for intermittent or unconfirmed faults, associated with Bear Cub ventilators. Where previous testing has been inadequate, computer logging is now used to interfac...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章
doi：
更新日期：1994-06-01 00:00:00
abstract：:In this paper, the peristaltic flow of rheologically complex physiological fluids when modelled by a non-Newtonian Casson fluid in a two-dimensional channel is considered. Of interest is the difference between peristaltic transport of Newtonian and non-Newtonian fluids. A perturbation series method of solution of the ...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章
doi：
更新日期：2000-09-01 00:00:00
abstract：:The Australasian College of Physical Scientists and Engineers in Medicine (ACPSEM) radiation oncology specialty group (ROSG) formed a series of working groups in 2011 to develop recommendations for guidance of radiation oncology medical physics practice within the Australasian setting. These recommendations are intend...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章,实务指引
doi：10.1007/s13246-015-0344-7
更新日期：2015-06-01 00:00:00
abstract：:In recent years there has been a significant economic growth in South East Asia, along with it a concurrent development of medical physics. The status of four countries--Malaysia, Thailand, the Philippines and Indonesia are presented. Medical physicists in these countries have been experiencing the usual problems of l...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章
doi：
更新日期：1997-03-01 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：:A study was made of calibrating the NACP plane parallel chamber in electron beams from linear accelerators of a different manufacture with energies, Ep,o' from 4.4 to 19.1 MeV, and also in 4 and 6 MV photon beams as well as a cobalt60 beam. The photon beam measurements were both IN-AIR and IN-PHANTOM. With the excepti...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章
doi：
更新日期：1996-09-01 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 effective energy of diagnostic X-rays is important for quality assurance (QA) and quality control (QC). However, the half-value layer (HVL), which is necessary to evaluate the effective energy, is not ubiquitously monitored because ionization-chamber dosimetry is time-consuming and complicated. To verify the appli...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章
doi：10.1007/BF03178625
更新日期：2009-03-01 00:00:00
abstract：:The angular distribution for electron beams produced by the Siemens KD-2 linear accelerator has been found by simulating electron transport through the scattering foils and air using two methods: Fermi-Eyges multiple Coulomb scattering calculations, and EGS4 Monte Carlo simulations. Fermi-Eyges theory gives solutions ...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章
doi：
更新日期：1994-09-01 00:00:00
abstract：:Fractal dimension has been proposed as a useful method for characterizing medical images. The fractal dimension is calculated from the average radial power spectrum of the image. However, simpler methods of calculation have been proposed. This paper examines a very simple and easily implemented method which has been p...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章
doi：
更新日期：1991-09-01 00:00:00
abstract：:Peripheral doses out of field could have short and long terms biological effects on patients treated with electron beams. In this study, peripheral dose outside the applicator was measured using the 6, 10 and 18 MeV beams of an Elekta synergy linac. For these beams dose profiles were measured using EBT3 film at variou...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章
doi：10.1007/s13246-018-0660-9
更新日期：2018-09-01 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：: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：:A set of four 4 MV photon beam compensators were produced, one for each field of a Hodgkins Disease treatment plan. The resultant dose profiles at various depths were measured by an ion chamber in water and by Kodak X-Omat V film in a Solid Water phantom, and compared to the doses calculated by a GE RT/Plan treatment ...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章
doi：
更新日期：1992-03-01 00:00:00
abstract：:X-ray transmission tests were performed on a Green-Lite (Infab Corporation) apron/vest combination, and compared to a number of other apron/vest combinations routinely used at Christchurch Hospital as well as a sheet of 0.5 mm lead. The materials were X-rayed using the primary beam of a Philips Optimus 50 X-ray machin...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章
doi：10.1007/BF03178704
更新日期：2005-06-01 00:00:00
abstract：:From the time when Roentgen and other physicists made the discoveries which led to the development of radiology, radiotherapy and nuclear medicine, medical physicists have played a pivotal role in the development of new technologies that have revolutionized the way medicine is practiced today. Medical physicists have ...
journal_title：Australasian physical & engineering sciences in medicine
pub_type：
doi：10.1007/BF03178583
更新日期：2008-06-01 00:00:00
abstract：:Given that there is increasing recognition of the effect that sub-millimetre changes in collimator position can have on radiotherapy beam dosimetry, this study aimed to evaluate the potential variability in small field collimation that may exist between otherwise matched linacs. Field sizes and field output factors we...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章
doi：10.1007/s13246-015-0349-2
更新日期：2015-06-01 00:00:00
abstract：:Accuracy of dwell position and reproducibility of dwell time are critical in high dose rate (HDR) brachytherapy. A phantom was designed to verify dwell position and dwell time reproducibility for an Ir-192 HDR stepping source using Computed Radiography (CR). The central part of the phantom, incorporating thin alternat...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章
doi：10.1007/s13246-012-0138-0
更新日期：2012-09-01 00:00:00
abstract：:It has long been recognized that the assessment of Automatic Exposure Control (AEC) function is an important criterion in the assessment of any general radiographic x-ray installation. Of the tests commonly performed on an AEC, only Beam Quality Dependence relates intimately with the optical density produced on the re...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章
doi：
更新日期：1997-09-01 00:00:00
abstract：:Laparoscopic ultrasound (LUS) has been widely utilized as a surgical aide in general, urological, and gynecological applications. Our study summarizes the clinical applications of laparoscopic ultrasonography in laparoscopic gynecologic surgery. Retrospective analyses were performed on 42 women subjects using laparosc...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章
doi：10.1007/s13246-015-0363-4
更新日期：2015-12-01 00:00:00
abstract：:Due to large inter- and intra-patient variabilities of arterial input functions (AIFs), accurately modeling and using patient-specific AIF are very important for quantitative analysis of dynamic contrast enhanced MRI. Computer simulations were performed to evaluate and compare nine population AIF models with the Parke...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章
doi：10.1007/s13246-018-0632-0
更新日期：2018-06-01 00:00:00
abstract：:Most of the human head models used in dipole localisation research, which have been reported in the literature to date, assume a simplified cranial structure wherein the head is modelled as a set of distinct homogenous tissue compartments. The inherent inhomogeneity of the tissues has so far been ignored in these mode...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章
doi：10.1007/BF03178283
更新日期：2001-03-01 00:00:00
abstract：:In-phantom figures of merit of the radiobiological dose distribution are the main criteria for evaluation of the boron neutron capture therapy (BNCT) plan and neutron beam evaluation. Since in BNCT there are several reactions, which contribute to the total dose of the tissue, the calculation of the dose distribution i...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章
doi：10.1007/s13246-011-0107-z
更新日期：2011-12-01 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：:Non-linear loading of the utilities supply introduced significant electromagnetic field (EMF) interference severe enough to disrupt electrocardiograph (ECG) monitoring and recordings in the new Emergency Department (ED) at the Royal Melbourne Hospital (RMH). This interference was evident even though standard Mu-metal ...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章
doi：10.1007/BF03178643
更新日期：2009-09-01 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
