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 necessary for three-dimensional treatment planning. A practical method of obtaining dose distributions for a given arrangement of beams and beam modifiers is with the aid of computer calculations based on mathematical formalisms derived from the principles of physics. The most accurate method of computing dose is by Monte Carlo stimulation of radiation transport. However, this method is extremely CPU time intensive and too complicated to implement for routine radiation treatment planning. Approximate semi-empirical methods have to be employed to compute dose distributions within reasonably short times. Conventional approximate methods do not yield results of adequate accuracy. Newer methods that are better able to take into account the three-dimensional nature of radiation transport have been introduced but require considerably greater computing capacity. Furthermore, computing power needs for dose calculations for three-dimensional treatment planning are one to two orders of magnitude greater than the corresponding needs of two-dimensional treatment planning. However, the concern for greater computing power requirements is being lessened somewhat with the advent of high speed computers and specialized hardware, and with the development of clever algorithms for speeding up dose calculations. For three-dimensional treatment planning some geometric issues, such as the calculation of dose at points in three-dimensional space, the incorporation of three-dimensional patient and beam geometry into a system for dose calculations, the choice of optimum grid spacing, radiological pathlength calculations, and algorithms for speeding up dose calculation, take on added importance compared to the corresponding issues for conventional two-dimensional planning. These issues are also discussed here briefly.
journal_name
Australas Phys Eng Sci Medjournal_title
Australasian physical & engineering sciences in medicineauthors
Mohan Rsubject
Has Abstractpub_date
1989-12-01 00:00:00pages
241-51issue
4eissn
0158-9938issn
1879-5447journal_volume
12pub_type
杂志文章abstract：:Shear wave elasticity imaging (SWEI) has been used to measure the local tissue elasticity. The local tissue shear modulus can be reconstructed from the displacement field of shear waves using an algebraic Helmholtz inversion (AHI) equation or a time-of-flight (TOF)-based algorithm. The shear waves, which are generated...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章
doi：10.1007/s13246-019-00748-3
更新日期：2019-09-01 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：: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：:In recent years, the use of gold nanoparticles in radiation therapy has been introduced as a new approach in radiotherapy. The aim of this study is to investigate the effect of gold nanoparticles (GNPs) in plaque brachytherapy for choroidal melanoma using Monte Carlo (MC) simulation. MCNPX code was used for simulation...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章
doi：10.1007/s13246-017-0555-1
更新日期：2017-09-01 00:00:00
abstract：:Mitral stenosis (MS) and mitral insufficiency (MI) have different pre-operative hemodynamic characteristics. However, it is unclear if there are differences in long-term echocardiographic characteristics of MS and MI patients after mechanical mitral valve replacement. This study is to compare long-term echocardiograph...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章
doi：10.1007/s13246-016-0521-3
更新日期：2017-03-01 00:00:00
abstract：:In this study, we assessed the accuracy of surface doses determined by direct measurement and treatment planning system (TPS) calculations, relative to benchmark Monte Carlo (MC) doses calculated at 70 μm for a 6 MV, 10 × 10 cm clinical radiotherapy beam. In a homogeneous phantom with both open and fixed wedged fields...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章
doi：10.1007/s13246-012-0145-1
更新日期：2012-09-01 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：:This paper describes a software tool developed for research into the use of an electronic portal imaging device (EPID) to verify dose for intensity modulated radiation therapy (IMRT) beams. A portal dose image prediction (PDIP) model that predicts the EPID response to IMRT beams has been implemented into a commerciall...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章
doi：10.1007/BF03179347
更新日期：2008-09-01 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：:The quality of phantom materials is crucial for accurate dosimetry in radiotherapy. A wide range of factors such as density, electron density and elemental composition can influence the radiation properties, and hence the absorbed dose, of materials. New materials can be tested by direct measurements which requires co...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章
doi：
更新日期：1993-09-01 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：: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：:Obesity management is a key point during cardiac rehabilitation. The effect of new index, waist circumference (WC), in the obesity management of cardiac rehabilitation is not clear yet. Therefore, our study compared the WC index to the body mass index (BMI) in the evaluation of obesity management for the patients with...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 临床试验,杂志文章
doi：10.1007/s13246-016-0471-9
更新日期：2016-12-01 00:00:00
abstract：:Aneurysm clips within stereotactic treatment volumes enhance spatial accuracy but perturb the dose distribution. The dose perturbations caused by a standard titanium alloy aneurysm clip (Ti6Al4V) have been measured with Gafchromic EBT film. The maximum dose perturbation was an increase of 6 % within 0.5 mm of the beam...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章
doi：10.1007/BF03178449
更新日期：2008-03-01 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
abstract：:The assignment of pathogenicity to variants suspected of causing an inherited retinal disease and the subsequent creation of molecular genetic reports sent to clinical geneticists and ophthalmologists has traditionally been time-consuming and subject to error and ambiguity. The purpose of this paper is to describe a c...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章
doi：10.1007/s13246-015-0420-z
更新日期：2016-03-01 00:00:00
abstract：:Improved technology and higher fidelity are making medical simulations increasingly popular. A simulated peripheral nerve stimulator and thumb actuator has been developed for use with the SimMan Universal Patient Simulator. This device incorporates a handheld control box, a McKibben pneumatic muscle and articulated th...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章
doi：
更新日期：2006-03-01 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：:There are many examples of technology transfer from astronomy to medicine, for example algorithms for reconstructing X-ray CT images were first developed for processing radio astronomy images. In more recent times, X-ray detectors developed for the Hubble Space Telescope have been used in a fine-needle breast biopsy s...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章
doi：10.1007/BF03178440
更新日期：2007-12-01 00:00:00
abstract：:The study developed two models of an innovative high-speed lancing device and safety lancet, where the specially designed structure causes high-speed motion of the lancet, resulting in only one puncture of the skin. The two experimental models and other lancing devices sold on market were compared in order to: (1) mea...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章
doi：10.1007/s13246-016-0490-6
更新日期：2016-12-01 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：:Electron beams can be used for the radiotherapy treatment of superficial cancers. In many cases of electron beam radiotherapy, tissue equivalent bolus material placed on the skin is to be used to enhance skin dose. An air gap might be present between the bolus and the skin due to variation in the patient contour. The ...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章
doi：10.1007/BF03178415
更新日期：2007-06-01 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：:Thermoluminescence dosimetry (TLD) is a versatile tool for the assessment of dose from ionising radiation. The wide variety of TLD materials and their different physical forms allow the determination of different radiation qualities at dose levels from microGy to kGy. Major advantages of TL dosimeters are their small ...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章,评审
doi：
更新日期：1994-12-01 00:00:00
abstract：:Electroencephalographic (EEG) signal records the neuronal activity in the brain and it is used in the diagnosis of epileptic seizure activities. Human inspection of non-stationary EEG signal for diagnosing epilepsy is cumbersome, time-consuming and inaccurate. In this paper an effective automatic approach to detect ep...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章
doi：10.1007/s13246-018-0697-9
更新日期：2018-12-01 00:00:00
abstract：:Despite ongoing active research, the role of the radiation bystander effect in modifying local tissue response to an ionising radiation dose remains unclear. The present study aims to provide new insight by simulating the diffusion-mediated inter-cellular communication processes in 2D and 3D cell-like structures to ca...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章
doi：10.1007/s13246-010-0048-y
更新日期：2011-04-01 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：:Large differences in monitor units have been observed when RadCalc, a pencil-beam-algorithm based software, is used to verify clinical electron plans from Raystation, a Monte-Carlo-algorithm based planning system. To investigate the problem, a number of clinical plans as well as test plans were created and calculated ...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章
doi：10.1007/s13246-016-0470-x
更新日期：2016-09-01 00:00:00
abstract：:Gravity associated with postural changes has a strong bearing on haemodynamics of blood flow in arteries. Its effect on stenosed cases has not been widely investigated. In the present study, variation observed in blood flow during postural changes is investigated for different conditions like standing, sleeping and he...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章
doi：10.1007/s13246-014-0246-0
更新日期：2014-03-01 00:00:00
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 ...
journal_title：Australasian physical & engineering sciences in medicine
pub_type： 杂志文章
doi：
更新日期：1996-12-01 00:00:00
