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Displaying publications 81 - 100 of 2007 in total

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Area assessment of psoriasis lesion for PASI scoring

Ihtatho D, Fadzil MH, Affandi AM, Hussein SH

Annu Int Conf IEEE Eng Med Biol Soc, 2007;2007:3446-9.
PMID: 18002738

Psoriasis is a skin disorder which is caused by genetic fault. There is no cure for psoriasis, however, there are many treatment modalities to help control the disease. To evaluate treatment efficacy, PASI (Psoriasis Area and Severity Index) which is the current gold standard method is used to measure psoriasis severity by evaluating the area, erythema, scaliness and thickness of the plaques. However, the calculation of PASI can be tedious and subjective. In this work, we develop a computer vision method that determines one of the PASI parameter, the lesion area. The method isolates healthy (or healed) skin areas from lesion areas by analyzing the hue and chroma information in the CIE L*a*b* colour space. Centroids of healthy skin and psoriasis in the hue-chroma space are determined from selected sample. Euclidean distance of all pixels from each centroid is calculated. Each pixel is assigned to the class with minimum Euclidean distance. The study involves patients from three different ethnic origins having different skin tones. Results obtained show that the proposed method is comparable to the dermatologist visual approach.

Matched MeSH terms: Reproducibility of Results
Determination of skin repigmentation progression

Nugroho H, Fadzil MH, Yap VV, Norashikin S, Suraiya HH

Annu Int Conf IEEE Eng Med Biol Soc, 2007;2007:3442-5.
PMID: 18002737

In this paper, we describe an image processing scheme to analyze and determine areas of skin that have undergone repigmentation in particular, during the treatment of vitiligo. In vitiligo cases, areas of skin become pale or white due to the lack of skin pigment called melanin. Vitiligo treatment causes skin repigmentation resulting in a normal skin color. However, it is difficult to determine and quantify the amount of repigmentation visually during treatment because the repigmentation progress is slow and moreover changes in skin color can only be discerned over a longer time frame typically 6 months. Here, we develop a digital image analysis scheme that can identify and determine vitiligo skin areas and repigmentation progression on a shorter time period. The technique is based on principal component analysis and independent component analysis which converts the RGB skin image into a skin image that represent skin areas due to melanin and haemoglobin only, followed by segmentation process. Vitiligo skin lesions are identified as skin areas that lack melanin (non-melanin areas). In the initial studies of 4 patients, the method has been able to quantify repigmentation in vitiligo lesion. Hence it is now possible to determine repigmentation progression objectively and treatment efficacy on a shorter time cycle.

Matched MeSH terms: Reproducibility of Results
Evaluation of medical image watermarking with tamper detection and recovery (AW-TDR)

Zain JM, Fauzi AR

Annu Int Conf IEEE Eng Med Biol Soc, 2007;2007:5662-5.
PMID: 18003297

This paper will study and evaluate watermarking technique by Zain and Fauzi [1]. Recommendations will then be made to enhance the technique especially in the aspect of recovery or reconstruction rate for medical images. A proposal will also be made for a better distribution of watermark to minimize the distortion of the Region of Interest (ROI). The final proposal will enhance AW-TDR in three aspects; firstly the image quality in the ROI will be improved as the maximum change is only 2 bits in every 4 pixels, or embedding rate of 0.5 bits/pixel. Secondly the recovery rate will also be better since the recovery bits are located outside the region of interest. The disadvantage in this is that, only manipulation done in the ROI will be detected. Thirdly the quality of the reconstructed image will be enhanced since the average of 2 x 2 pixels would be used to reconstruct the tampered image.

Matched MeSH terms: Reproducibility of Results
Body surface area measurement and soft clustering for PASI area assessment

Hani AF, Prakasa E, Nugroho H, Affandi AM, Hussein SH

Annu Int Conf IEEE Eng Med Biol Soc, 2012;2012:4398-401.
PMID: 23366902 DOI: 10.1109/EMBC.2012.6346941

Psoriasis is a common skin disorder with a prevalence of 0.6 - 4.8% around the world. The most common is plaques psoriasis and it appears as red scaling plaques. Psoriasis is incurable but treatable in a long term treatment. Although PASI (Psoriasis Area and Severity Index) scoring is recognised as gold standard for psoriasis assessment, this method is still influenced by inter and intra-rater variation. An imaging and analysis system called α-PASI is developed to perform PASI scoring objectively. Percentage of lesion area to the body surface area is one of PASI parameter. In this paper, enhanced imaging methods are developed to improve the determination of body surface area (BSA) and lesion area. BSA determination method has been validated on medical mannequin. BSA accuracies obtained at four body regions are 97.80% (lower limb), 92.41% (trunk), 87.72% (upper limb), and 83.82% (head). By applying fuzzy c-means clustering algorithm, the membership functions of lesions area for PASI area scoring have been determined. Performance of scoring result has been tested with double assessment by α-PASI area algorithm on body region images from 46 patients. Kappa coefficients for α-PASI system are greater than or equal to 0.72 for all body regions (Head - 0.76, Upper limb - 0.81, Trunk - 0.85, Lower limb - 0.72). The overall kappa coefficient for the α-PASI area is 0.80 that can be categorised as substantial agreement. This shows that the α-PASI area system has a high reliability and can be used in psoriasis area assessment.

Matched MeSH terms: Reproducibility of Results
An expectation-maximization algorithm based Kalman smoother approach for single-trial estimation of event-related potentials

Ting CM, Samdin SB, Salleh ShH, Omar MH, Kamarulafizam I

Annu Int Conf IEEE Eng Med Biol Soc, 2012;2012:6534-8.
PMID: 23367426 DOI: 10.1109/EMBC.2012.6347491

This paper applies an expectation-maximization (EM) based Kalman smoother (KS) approach for single-trial event-related potential (ERP) estimation. Existing studies assume a Markov diffusion process for the dynamics of ERP parameters which is recursively estimated by optimal filtering approaches such as Kalman filter (KF). However, these studies only consider estimation of ERP state parameters while the model parameters are pre-specified using manual tuning, which is time-consuming for practical usage besides giving suboptimal estimates. We extend the KF approach by adding EM based maximum likelihood estimation of the model parameters to obtain more accurate ERP estimates automatically. We also introduce different model variants by allowing flexibility in the covariance structure of model noises. Optimal model selection is performed based on Akaike Information Criterion (AIC). The method is applied to estimation of chirp-evoked auditory brainstem responses (ABRs) for detection of wave V critical for assessment of hearing loss. Results shows that use of more complex covariances are better estimating inter-trial variability.

Matched MeSH terms: Reproducibility of Results
Dimensionality and psychometric properties of an Italian translation of the Intuitive Eating Scale-2 (IES-2): An assessment using a bifactor exploratory structural equation modelling framework

Swami V, Maïano C, Todd J, Ghisi M, Cardi V, Bottesi G, et al.

Appetite, 2021 11 01;166:105588.
PMID: 34224761 DOI: 10.1016/j.appet.2021.105588

The construct of intuitive eating is most often measured using the 23-item Intuitive Eating Scale-2 (IES-2), but previous studies have typically relied solely on confirmatory factor analysis (CFA) to understand IES-2 dimensionality. In contrast, a bifactor exploratory structural equation modelling (B-ESEM) framework offers a more realistic account of IES-2 multidimensionality. Here, we assessed the psychometric properties of a novel Italian translation using a combination of exploratory factor analysis and B-ESEM. A total of 950 adults completed the IES-2 alongside measures of positive body image, disordered eating, and psychological well-being. Results indicated that a 4-factor B-ESEM model had adequate fit to the data and that fit was improved when the correlated uniqueness of seven negatively worded IES-2 items was accounted for. This model of IES-2 scores showed adequate internal consistency and good test-retest reliability up to three weeks. Evidence of construct validity was good in terms of a global IES-2 factor, and broadly supported in terms of its specific-factors. These results highlight the utility of a B-ESEM framework for understanding the dimensionality of IES-2 scores and may help scholars better understand the extent to which the IES-2 adequately operationalises the construct of intuitive eating.

Matched MeSH terms: Reproducibility of Results
Evaluation of aeration strategy in moving bed sequencing batch reactor performing simultaneous 4-chlorophenol and nitrogen removal

Lim JW, Lim PE, Seng CE, Adnan R

Appl Biochem Biotechnol, 2013 Jun;170(4):831-40.
PMID: 23613119 DOI: 10.1007/s12010-013-0245-8

The aeration strategy ranging from intermittent to continuous aeration in the REACT period of moving bed sequencing batch reactor (MBSBR) was evaluated for simultaneous removal of 4-chlorophenol (4-CP) and nitrogen. The results show that the removal rates of 4-CP and ammonium nitrogen (NH(4)(+)-N) increased with the increase of continuous aeration period. In the presence of 4-CP, NH(4)(+)-N removal was mainly by the assimilation process. The removal of NH(4)(+)-N to oxidized nitrogen via oxidation was only observed after 4-CP was completely degraded with sufficient aeration period provided indicating the inhibitory effect of 4-CP on nitrification. As the intermittent aeration strategy would lead to slower 4-CP degradation resulting in the delay of nitrification process, continuous aeration would be the preferred strategy in the simultaneous removal of 4-CP and nitrogen in the MBSBR system.

Matched MeSH terms: Reproducibility of Results
Proteomics and detection of uromodulin in first-time renal calculi patients and recurrent renal calculi patients

Wai-Hoe L, Wing-Seng L, Ismail Z, Lay-Harn G

Appl Biochem Biotechnol, 2009 Oct;159(1):221-32.
PMID: 19145410 DOI: 10.1007/s12010-008-8503-x

Renal calculi disease or known as kidney stone disease is the most common urological disorder in both men and women, although it is more prevalent in men. The lifetime chance for an individual to develop renal calculi is approximately 10% whereas the risk of recurrence in a 10-year period is 74%. Therefore, a diagnostic tool for screening or detecting renal calculi is greatly needed. In this study, we analyze urinary protein profiles from patients with renal calculi for the first time (RC), healthy subjects (HS), and patients with recurrent renal calculi (RRC) to identify a biomarker for detecting the disease. Urinary proteins were isolated by salt precipitation and the proteins resolved by SDS-PAGE. Target proteins were analyzed with LC/MS/MS. Thirty-two proteins were identified from healthy subjects and patients. Uromodulin was the most abundant urinary protein in HS but was a very faint band if detected at all from those that formed renal calculi for the first time (p < 0.05). Yet the excreted levels of urinary uromodulin in RRC were similar to those of the HS suggesting that uromodulin is a reliable biomarker for only RC. In addition, a few immunoglobulins that were commonly found in the urine of both RC and RRC, which include Ig alpha heavy chain 1, Ig gamma-2 c region, Ig gamma-3 heavy chain disease protein, Ig heavy chain variable region, Ig heavy constant region gamma 4, and Ig heavy chain. Ig heavy chain Fab frag and antibody a5b7 chain B may serve as potential biomarkers for renal calculi disease.

Matched MeSH terms: Reproducibility of Results
Development and Validation of SafeHIT: An Instrument to Assess the Self-Reported Safe Use of Health Information Technology

Salahuddin L, Ismail Z, Abdul Rahim F, Anawar S, Hashim UR

Appl Clin Inform, 2023 Aug;14(4):693-704.
PMID: 37648223 DOI: 10.1055/s-0043-1771394

BACKGROUND: Implementing health information technology (HIT) may cause unintended consequences and safety risks when incorrectly designed and used. Yet, the tools to assess self-reported safe use of HIT are not well established.
OBJECTIVE: This study aims to develop and validate SafeHIT, an instrument to assess self-reported safe use of HIT among health care practitioners.
METHODS: Systematic literature review and a semistructured interview with 31 experts were adopted to generate SafeHIT instrument items. In total, 450 physicians from various departments at three Malaysian public hospitals participated in the questionnaire survey to validate SafeHIT. Exploratory factor analysis and confirmatory factor analysis (CFA) were undertaken to explore the items that best represent a specific construct and to confirm the reliability and validity of the SafeHIT, respectively.
RESULTS: The final SafeHIT consisted of 14 constructs and 58 items in total. The result of the CFA confirmed that all constructs demonstrated adequate convergent and discriminant validity.
CONCLUSION: A reliable and valid theoretically underpinned measure of determinants of safe HIT use behavior has been developed. Understanding external factors that influence safe HIT use is useful for developing targeted interventions that favor the quality and safety of health care.

Matched MeSH terms: Reproducibility of Results
Validity and reliability of the Neuropsychological Assessment Battery - Screening Module (S-NAB) in a subset of Malaysian population with mild traumatic brain injury (mTBI)

Hamzah N, Mohamad NA, Thiruselvam I, Hariri F, Veeramuthu V, Mazlan M, et al.

Appl Neuropsychol Adult, 2019 08 21;28(4):416-426.
PMID: 31431094 DOI: 10.1080/23279095.2019.1648264

This study assessed the validity (construct validity) and reliability (internal consistency) of the Neuropsychological Assessment Battery Screening Module (S-NAB) in detecting mild cognitive deficit/alteration in multicultural, multilingual, and multiethnic mild traumatic brain injury (mTBI) population of Malaysia. S-NAB and Montreal Cognitive Assessment (MoCA) data from 114 patients with mTBI (93 males; 21 females) aged 18 to 60 years old were obtained at University Malaya Medical Center, Malaysia. The mean age was 28.17 ± 8.57 years and mean education years was 12.40 ± 2.01. Convergent validity was assessed between S-NAB domain scores and MoCA total scores by using Pearson's correlation and internal consistency was assessed using Cronbach's alpha. Acceptable internal consistency (α ≥ .70) was found for Attention, Language, and Memory domains but weak internal consistencies (α

Matched MeSH terms: Reproducibility of Results
Thermoluminescence characteristics of Ge-doped optical fibers with different dimensions for radiation dosimetry

Begum M, Rahman AK, Abdul-Rashid HA, Yusoff Z, Begum M, Mat-Sharif KA, et al.

Appl Radiat Isot, 2015 Jun;100:79-83.
PMID: 25468288 DOI: 10.1016/j.apradiso.2014.10.025

Important thermoluminescence (TL) properties of five (5) different core sizes Ge-doped optical fibers have been studied to develop new TL material with better response. These are drawn from same preform applying different speed and tension during drawing phase to produce Ge-doped optical fibers with five (5) different core sizes. The results of the investigations are also compared with most commonly used standard TLD-100 chips (LiF:Mg,Ti) and commercial multimode Ge-doped optical fiber (Yangtze Optical Fiber, China). Scanning Electron Microscope (SEM) and EDX analysis of the fibers are also performed to map Ge distribution across the deposited region. Standard Gamma radiation source in Secondary Standard Dosimetry Lab (SSDL) was used for irradiation covering dose range from 1Gy to 10Gy. The essential dosimetric parameters that have been studied are TL linearity, reproducibility and fading. Prior to irradiation all samples ∼0.5cm length are annealed at temperature of 400°C for 1h period to standardize their sensitivities and background. Standard TLD-100 chips are also annealed for 1h at 400°C and subsequently 2h at 100°C to yield the highest sensitivity. TL responses of these fibers show linearity over a wide gamma radiation dose that is an important property for radiation dosimetry. Among all fibers used in this study, 100μm core diameter fiber provides highest response that is 2.6 times than that of smallest core (20μm core) optical fiber. These fiber-samples demonstrate better response than commercial multi-mode optical fiber and also provide low degree of fading about 20% over a period of fifteen days for gamma radiation. Effective atomic number (Zeff) is found in the range (13.25-13.69) which is higher than soft tissue (7.5) however within the range of human-bone (11.6-13.8). All the fibers can also be re-used several times as a detector after annealing. TL properties of the Ge-doped optical fibers indicate promising applications in ionizing radiation dosimetry.

Matched MeSH terms: Reproducibility of Results
Internal radiation dosimetry of orally administered radiotracers for the assessment of gastrointestinal motility

Yeong CH, Ng KH, Abdullah BJJ, Chung LY, Goh KL, Perkins AC

Appl Radiat Isot, 2014 Dec;94:216-220.
PMID: 25222875 DOI: 10.1016/j.apradiso.2014.08.009

Radionuclide imaging using (111)In, (99m)Tc and (153)Sm is commonly undertaken for the clinical investigation of gastric emptying, intestinal motility and whole gut transit. However the documented evidence concerning internal radiation dosimetry for such studies is not readily available. This communication documents the internal radiation dosimetry for whole gastrointestinal transit studies using (111)In, (99m)Tc and (153)Sm labeled formulations. The findings were compared to the diagnostic reference levels recommended by the United Kingdom Administration of Radioactive Substances Advisory Committee, for gastrointestinal transit studies.

Matched MeSH terms: Reproducibility of Results
Thermoluminescence properties of the Cu-doped lithium potassium borate glass

Aboud H, Wagiran H, Hussin R, Ali H, Alajerami Y, Saeed MA

Appl Radiat Isot, 2014 Aug;90:35-9.
PMID: 24681645 DOI: 10.1016/j.apradiso.2014.01.012

Characteristics of lithium potassium borate glasses with various copper concentrations are reported. The glasses were prepared by the melt quenching method and irradiated with photons to doses in the 0.5-4.0 Gy range. Glowing curves, dose response curves, reproducibility of the response, dose threshold, thermal fading and optical bleaching were studied.

Matched MeSH terms: Reproducibility of Results
Luminescence characteristics of Li₂CO₃-K₂CO₃-H₃BO₃ glasses co-doped with TiO₂/MgO

Alajerami YS, Hashim S, Ghoshal SK, Ramli AT, Saleh MA, Ibrahim Z, et al.

Appl Radiat Isot, 2013 Dec;82:12-9.
PMID: 23948307 DOI: 10.1016/j.apradiso.2013.07.005

Understanding the influence of co-dopants in the luminescence enhancement of carbonate glasses is the key issue in dosimetry. A series of borate glasses modified by lithium and potassium carbonate were synthesized by the melt-quenching method. The glass mixture activated with various concentrations of TiO2 and MgO was subjected to various doses of gamma-rays ((60)Co). The amorphous nature of the samples was confirmed by x-ray diffraction (XRD) spectra. The simple glowing curve of the glass doped with TiO2 features a peak at 230°C, whose intensity is maximal at 0.5 mol% of the dopant. The intensity of the glowing curve increases with the concentration of MgO added as a co-dopant up to 0.25 mol%, where it is two times higher than for the material without MgO thermoluminescence properties, including dose response, reproducibility, and fading were studied. The effective atomic number of the material was also determined. Kinetic parameters, such as kinetics order, activation energy, and frequency factor are estimated. The photoluminescence spectra of the titanium-doped glass consist of a prominent peaks at 480 nm when laser excitation at 650 nm is used. A three-fold photoluminescence enhancement and a blue shift of the peak were observed when 0.1% MgO was introduced. In addition, various physical parameters, such as ion concentration, polaron radius and internuclear distances were calculated. The mechanism for the thermoluminescence and photoluminescence enhancements are discussed.

Matched MeSH terms: Reproducibility of Results
Reproducibility of neutron activated Sm-153 oral dose formulations intended for human administration

Yeong CH, Blackshaw PE, Ng KH, Abdullah BJ, Blaauw M, Dansereau RJ, et al.

Appl Radiat Isot, 2011 Sep;69(9):1181-4.
PMID: 21550260 DOI: 10.1016/j.apradiso.2011.04.017

Neutron activation of Sm-152 offers a method of radiolabeling for the in vivo study of oral dose formulations by gamma scintigraphy. Reproducibility measurements are needed to ensure the robustness of clinical studies. 204 enteric-coated guaifenesin core tablets (10mg of Sm(2)O(3)) were irradiated by thermal neutrons to achieve 1 MBq at 48 h. Administered activities were 0.86±0.03 MBq. Good reproducibility (CV=3.5%) was observed over 24 weeks ensuring that volunteer doses were within the dose reference level of 0.8 mSv.

Matched MeSH terms: Reproducibility of Results
The thermoluminescence response of doped SiO2 optical fibres subjected to fast neutrons

Hashim S, Bradley DA, Saripan MI, Ramli AT, Wagiran H

Appl Radiat Isot, 2010 Apr-May;68(4-5):700-3.
PMID: 19892557 DOI: 10.1016/j.apradiso.2009.10.027

This paper describes a preliminary study of the thermoluminescence (TL) response of doped SiO(2) optical fibres subjected to (241)AmBe neutron irradiation. The TL materials, which comprise Al- and Ge-doped silica fibres, were exposed in close contact with the (241)AmBe source to obtain fast neutron interactions through use of measurements obtained with and without a Cd filter (the filter being made to entirely enclose the fibres). The neutron irradiations were performed for exposure times of 1-, 2-, 3-, 5- and 7-days in a neutron tank filled with water. In this study, use was also made of the Monte Carlo N-particle (MCNP) code version 5 (V5) to simulate the neutron irradiations experiment. It was found that the commercially available Ge-doped and Al-doped optical fibres show a linear dose response subjected to fast neutrons from (241)AmBe source up to seven days of irradiations. The simulation performed using MCNP5 also exhibits a similar pattern, albeit differing in sensitivity. The TL response of Ge-doped fibre is markedly greater than that of the Al-doped fibre, the total absorption cross section for Ge in both the fast and thermal neutrons region being some ten times greater than that of Al.

Matched MeSH terms: Reproducibility of Results
Gamma irradiated thermoluminescence response of Ge-doped SiO2 fibre

Wahib N, Zulkepely NN, Mat Nawi SN, Amin YM, Ling YS, Abdul Sani SF, et al.

Appl Radiat Isot, 2015 Nov;105:158-162.
PMID: 26313622 DOI: 10.1016/j.apradiso.2015.08.025

Over the past decade and more, considerable interest has been shown in the thermoluminescence (TL) properties of silica-based single-mode optical fibres, in particular investigating potential ionising radiation dosimetry applications. Herein, study has been made of TL glow curve, dose response, reproducibility and fading of 6mol% Ge-doped silica, fabricated in-house and produced in the form of cylindrical fibres. Three different pairings of doped-core and silica cladding diameters were produced: (40, 241)µm, (80, 483)µm and (100, 604)µm. The TL results were compared against that of TLD-100, one of the most sensitive commercially available LiF-based TL media. For all three pairings of diameters, closely similar TL glow curve were obtained, formed of a single peaked structure with a maximum TL yield located between the temperatures 250 and 310°C. The TL yield of the fibres were linear over the range of doses investigated, from 1Gy up to 10Gy, their dose response exceeding that of TLD-100, the samples also being found to be reusable, without evidence of degradation.

Matched MeSH terms: Reproducibility of Results
Carbon nanotubes buckypaper radiation studies for medical physics applications

Alanazi A, Alkhorayef M, Alzimami K, Jurewicz I, Abuhadi N, Dalton A, et al.

Appl Radiat Isot, 2016 Nov;117:106-110.
PMID: 26777569 DOI: 10.1016/j.apradiso.2016.01.001

Graphite ion chambers and semiconductor diode detectors have been used to make measurements in phantoms but these active devices represent a clear disadvantage when considered for in vivo dosimetry. In such circumstance, dosimeters with atomic number similar to human tissue are needed. Carbon nanotubes have properties that potentially meet the demand, requiring low voltage in active devices and an atomic number similar to adipose tissue. In this study, single-wall carbon nanotubes (SWCNTs) buckypaper has been used to measure the beta particle dose deposited from a strontium-90 source, the medium displaying thermoluminescence at potentially useful sensitivity. As an example, the samples show a clear response for a dose of 2Gy. This finding suggests that carbon nanotubes can be used as a passive dosimeter specifically for the high levels of radiation exposures used in radiation therapy. Furthermore, the finding points towards further potential applications such as for space radiation measurements, not least because the medium satisfies a demand for light but strong materials of minimal capacitance.

Matched MeSH terms: Reproducibility of Results
The thermoluminescence glow curve and the deconvoluted glow peak characteristics of erbium doped silica fiber exposed to 70-130 kVp x-rays

Alawiah A, Bauk S, Marashdeh MW, Nazura MZ, Abdul-Rashid HA, Yusoff Z, et al.

Appl Radiat Isot, 2015 Oct;104:197-202.
PMID: 26188687 DOI: 10.1016/j.apradiso.2015.07.011

In regard to thermoluminescence (TL) applied to dosimetry, in recent times a number of researchers have explored the role of optical fibers for radiation detection and measurement. Many of the studies have focused on the specific dopant concentration, the type of dopant and the fiber core diameter, all key dependencies in producing significant increase in the sensitivity of such fibers. At doses of less than 1 Gy none of these investigations have addressed the relationship between dose response and TL glow peak behavior of erbium (Er)-doped silica cylindrical fibers (CF). For x-rays obtained at accelerating potentials from 70 to 130 kVp, delivering doses of between 0.1 and 0.7 Gy, present study explores the issue of dose response, special attention being paid to determination of the kinetic parameters and dosimetric peak properties of Er-doped CF. The effect of dose response on the kinetic parameters of the glow peak has been compared against other fiber types, revealing previously misunderstood connections between kinetic parameters and radiation dose. Within the investigated dose range there was an absence of supralinearity of response of the Er-doped silica CF, instead sub-linear response being observed. Detailed examination of glow peak response and kinetic parameters has thus been shown to shed new light of the rarely acknowledged issue of the limitation of TL kinetic model and sub-linear dose response of Er-doped silica CF.

Matched MeSH terms: Reproducibility of Results
Commercial kitchenware glass as a potential thermoluminescent media for retrospective dosimetry

Wahib NB, Khandaker MU, Aqilah Binti Mohamad Ramli N, Sani SFA, Bradley DA

Appl Radiat Isot, 2019 Jun;148:218-224.
PMID: 31003071 DOI: 10.1016/j.apradiso.2019.04.001

Study has been made of the thermoluminescence (TL) yield of various glass-based commercial kitchenware (Reko-China, Skoja-France, Godis-China, Glass Tum-Malaysia, Lodrat-France). Interest focuses on their potential for retrospective dosimetry. Use was made of a60Co gamma-ray irradiator, delivering doses in the range 2-10 Gy. Results for the various media show all the glassware brands to yield linearity of response against dose, with a lower limit of detection of ∼0.06 and ∼0.08 Gy for loose and compact powdered samples. Among all of the brands under study, the Lodrat glassware provides the greatest sensitivity, at 6.0 E+02 nC g-1 Gy-1 and 1.5E+03 nC g-1 Gy-1 for compact- and loose-powdered forms respectively. This is sufficiently sensitive to allow its use as a TL material for accident dosimetry (2 Gy being the threshold dose for the onset of a number of deterministic biological effects, including skin erythema and sterility). Energy Dispersive X-ray (EDX) analyses have been conducted, showing the presence of a number of impurities (including C, O, Na, Mg, Al, Si, Ca and Br). Fading of the irradiated glasses show the amount of better than 3% and 5% of the stored energy for both loose and compact powdered samples within 9 days post irradiation. As such, commercial kitchenware glass has the potential to act as relatively good TL material for gamma radiation dosimetry at accident levels. This is the first endeavour reporting the TL properties of low cost commercial kitchenware glasses for gamma-ray doses in the few Gy range, literature existing for doses from 8 Gy to 200 Gy.

Matched MeSH terms: Reproducibility of Results

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