ORCID Profile
0000-0003-0854-2077
Current Organisations
Monash University
,
RMIT University
,
Peter MacCallum Cancer Centre
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Publisher: IOP Publishing
Date: 03-10-2023
Publisher: Elsevier BV
Date: 08-2022
DOI: 10.1016/J.EJMP.2022.06.001
Abstract: To investigate the current status of radiation treatment facilities in Sri Lanka and to explore future possibilities required to adequately address increasing cancer care. Hospitals with radiation therapy facilities from across the country were identified. Data pertaining to the types of radiotherapy equipment, radiation oncology staffing, and radiotherapy education were collected by onsite visit, conversation over the phone, and from other available cancer resources in Sri Lanka. Seven government hospitals and two private sectors were identified with radiation therapy facilities over nine provinces in Sri Lanka for 21.4 million people. At present, there are twenty megavoltage machines (MVMs) operating. This is 0.93 MVMs per one million people. After completion of proposed radiotherapy facilities, it will be able to provide 1.21 MVMs per million people. In addition, multidisciplinary staffing has also been identified as inadequate. There is a significant shortfall in radiotherapy facilities and workforce in Sri Lanka. The current and future scope of radiation facilities is sub-optimal compared to internationally recognized guidelines.
Publisher: Springer Singapore
Date: 30-05-2019
Publisher: Medknow
Date: 2017
Publisher: Optica Publishing Group
Date: 2005
Abstract: Fluorescence spectroscopy has been used to measure fluorescence quantum efficiency (QE) of dried Bacillus spores (washed and unwashed) fixed to a quartz substrate. Fluorescence spectra and QE of anthracene in ethanol was used as the standard. We measured the absorption and fluorescence signal of the spores as a function of the number of spores. The absorption was measured from 600 nm to 250 nm using the reflectance in an integrating sphere. The fluorescence spectra were measured using excitation wavelengths at 280, 360 and 400 nm at room temperature. The absorption cross sections for the unwashed spores were 1.3 x 10-8, 8 x 10-9, and 5 x 10-9 mm2/spore at 280, 360 and 400 nm, respectively. The fluorescence QE was 0.13 +/- 0.03, 0.33 +/- 0.12 and 0.43 +/- 0.26 at 280, 360, and 400 nm, respectively. The QE decreased by a factor of 2, 4 and 4 at these same wavelengths after washing and redrying the spores.
Publisher: Optica Publishing Group
Date: 03-2005
DOI: 10.1364/AO.44.001182
Abstract: Dipicolinic acid (DPA) and the Ca2+ complex of DPA (CaDPA) are major chemical components of bacterial spores. With fluorescence being considered for the detection and identification of spores, it is important to understand the optical properties of the major components of the spores. We report in some detail on the room-temperature fluorescence excitation and emission spectra of DPA and its calcium ion complex and provide a comparison of the excitation-emission spectrum in a dry, wet paste and aqueous form. DPA solutions have weak, if any, fluorescence, with increased fluorescence when the DPA is dry. After exposure to a broad source UV light of the DPA, wet or dry, we observe a large increase in fluorescence with a maximum intensity emission peak at around 440 nm for excitation light with a wavelength of around 360 nm. There is a slight blueshift in the absorption spectra of UV-exposed DPA from the unexposed DPA solution. CaDPA in solution shows a slight fluorescence with increased fluorescence in the dry form, and a substantial increase of fluorescence was observed after UV exposure with an emission peak of around 410 nm for excitation around 305 nm. The detailed excitation-emission spectra are necessary for better interpretation of the fluorescence spectra of bacterial spores where DPA is a major chemical component.
Publisher: Informa UK Limited
Date: 09-2005
Publisher: Springer Science and Business Media LLC
Date: 26-08-2019
DOI: 10.1007/S13246-019-00789-8
Abstract: We propose a simple and efficient method to measure beam attenuation in one or two dimensions using an amorphous silicon electronic portal imaging device (a-Si EPID). The proposed method was validated against ionization chamber measurements. Beam attenuation through treatment couches (Varian Medical Systems) and immobilization devices (CIVCO Radiotherapy, USA) was examined. The dependency of beam attenuation on field size, photon energy, thickness of the couch, and the presence of a phantom were studied. Attenuation images were derived by computing the percentage difference between images obtained without and with a couch or immobilization devices determining the percentage of attenuation at the center and the mean attenuation. The beam attenuation measurements obtained with an a-Si EPID and an ionization chamber agreed to within ± 0.10 to 1.80%. No difference was noted between the center and mean of an attenuated image for a small field size of 5 × 5 cm
Publisher: Elsevier BV
Date: 10-2019
DOI: 10.1016/J.EJMP.2019.09.079
Abstract: The increased use of medical imaging and radiation therapies has resulted in a high demand for medical physicists. Although medical physics programmes are well established in advanced countries, the same cannot be said for many low- and medium-income countries. In some countries, there may be huge variations in the graduates' skill and quality, which pose a problem in ensuring patient safety, providing quality assurance in treatments, optimisation of protocols and standardisation of quality. It also makes any yet-to-be-established regional peer recognition efforts problematic. In order to understand the depth of this problem, a survey was carried out as part of the home-based assignment under the RAS 6088 IAEA programme. A large ersity in terms of course content, duration, clinical training and student profile could be observed across the Asia-Oceania universities surveyed. Out of 25 programmes, only six received recognition from professional bodies, and they were mostly in Australia and New Zealand. Hence, to ensure quality education, a regional curriculum model needs to be developed to harmonise standards. And there is still a long way to go towards standardizing medical physics education and clinical training in the region.
Publisher: Wiley
Date: 30-11-2022
DOI: 10.1002/ACM2.13852
Abstract: The present study was conducted as part of a comprehensive work to establish National Diagnostic Reference Levels (NDRLs) in Sri Lanka for the first time. DRLs can be used as an effective optimization tool for identifying unusually high or low patient doses during X-ray examinations. This study aims to propose institutional DRLs (IDRLs) by measuring the kerma-area product (KAP) of adult patients undergoing routine projection X-ray examinations. The median and the 75th percentile KAP values obtained were compared with that of the single institution KAP values reported from India and Greece. This descriptive cross-sectional study was conducted in a public hospital in Uva province, Sri Lanka, with 400 adult patients aged 18-87 years and weighing 58 ± 20 kg. The patient-specific information (age, sex, weight, and height) and corresponding exposure parameters (tube voltage and current-exposure time product) were obtained. The KAP values were measured, and descriptive statistics were utilized for data analysis. The median KAP values obtained were proposed as IDRLs. The IDRLs in Gy.cm
Publisher: Springer Science and Business Media LLC
Date: 18-08-2015
DOI: 10.1007/S13246-015-0342-9
Abstract: The history of medical physics in Asia-Oceania goes back to the late nineteenth century when X-ray imaging was introduced, although medical physicists were not appointed until much later. Medical physics developed very quickly in some countries, but in others the socio-economic situation as such prevented it being established for many years. In others, the political situation and war has impeded its development. In many countries their medical physics history has not been well recorded and there is a danger that it will be lost to future generations. In this paper, brief histories of the development of medical physics in most countries in Asia-Oceania are presented by a large number of authors to serve as a record. The histories are necessarily brief otherwise the paper would quickly turn into a book of hundreds of pages. The emphasis in each history as recorded here varies as the focus and culture of the countries as well as the length of their histories varies considerably.
Publisher: Springer International Publishing
Date: 2015
Publisher: Optica Publishing Group
Date: 20-05-2006
DOI: 10.1364/AO.45.003659
Abstract: The fluorescence spectra of Bacillus spores are measured at excitation wavelengths of 280, 310, 340, 370, and 400 nm. When cluster analysis is used with the principal-component analysis, the Bacillus globigii spores can be distinguished from the other species of Bacillus spores (B. cereus, B. popilliae, and B. thuringiensis). To test how robust the identification process is with the fluorescence spectra, the B. globigii is obtained from three separate preparations in different laboratories. Furthermore the fluorescence is measured before and after washing and redrying the B. globigii spores. Using the cluster analysis of the first two or three principal components of the fluorescence spectra, one is able to distinguish B. globigii spores from the other species, independent of preparing or washing the spores.
Publisher: Elsevier BV
Date: 05-2005
Publisher: Springer Science and Business Media LLC
Date: 09-2015
Location: Sri Lanka
No related grants have been discovered for Sivananthan Sarasanandarajah.