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Multielement analysis of human hair and kidney stones by instrumental neutron activation analysis with the k0-standardization method

Abugassa I, Sarmani SB, Samat SB

Appl Radiat Isot, 1999 Jun;50(6):989-94.
PMID: 10355102

This paper focuses on the evaluation of the k0 method of instrumental neutron activation analysis in biological materials. The method has been applied in multielement analysis of human hair standard reference materials from IAEA, No. 085, No. 086 and from NIES (National Institute for Environmental Sciences) No. 5. Hair samples from people resident in different parts of Malaysia, in addition to a sample from Japan, were analyzed. In addition, human kidney stones from members of the Malaysian population have been analyzed for minor and trace elements. More than 25 elements have been determined. The samples were irradiated in the rotary rack (Lazy Susan) at the TRIGA Mark II reactor of the Malaysian Institute for Nuclear Technology and Research (MINT). The accuracy of the method was ascertained by analysis of other reference materials, including 1573 tomato leaves and 1572 citrus leaves. In this method the deviation of the 1/E1+ alpha epithermal neutron flux distribution from the 1/E law (P/T ratio) for true coincidence effects of the gamma-ray cascade and the HPGe detector efficiency were determined and corrected for.
The specific absorbed dose constant: comparison of values published for 60Co photons

Samat SB, Evans CJ

Radiat Prot Dosimetry, 2003;103(4):341-7.
PMID: 12797557

For the specific absorbed dose constant for 60Co photons, three values quoted directly in the literature and two derived indirectly from published information are reported. The three publications giving the direct values mentioned no medium of absorption, whereas the other two specify tissue. A database of the specific absorbed dose constant is generated for each of 14 media namely air, water, bone and 11 types of soft tissue. These values are consistent with the three directly quoted values plus one of the indirectly obtained values. Air is found to be unlikely as the medium for the first three; and appropriate media for these are suggested. For the other two values, the generated database suggests that one is too small to be accurate; while the other is correct for tissue (as stated in the publication). An apparent error of 10(3) is identified in one of the values directly quoted.
Fulltext Absorbed Dose to Water Determination Using IAEA, HPA, NACP, AAPM, NCRP and ICRU Protocols for 1.25 MeV Gamma Ray 6 MV and 10 MV X-Rays: An Intercomparison of Results when IAEA was taken as a Standard Protocol

Dolah MT, Samat SB, Kadni T

Malays J Med Sci, 2000 Jan;7(1):47-53.
PMID: 22844215

Absorbed dose to water was measured with ionisation chambers NE 2561 (#267), NE 2581 (#334), NE 2571 (#1028), using the IAEA standard water phantom. The ionisation chamber was inserted in the water phantom at a reference depth dependent on the type of the radiation quality used. Three radiation qualities were used namely 1.25 MeV gamma ray, 6 MV x-rays and 10 MV x-rays. The values of the absorbed dose to water were determined by the N(K)- and N(X)- based methods, i.e with the use of IAEA, HPA, NACP, AAPM, NCRP and ICRU protocols. The aim of this study was to make an intercomparison of the results, by taking the IAEA protocol as a standard. The largest deviation contributed by any of these protocols was recorded for each quality. It was found that AAPM, NCRP and ICRU protocols contributed 0.94% for 1.25 MeV gamma ray, NACP contributed 2.12% for the 6 MV x-rays, and NACP contributed 2.35% for 10 MV x-rays. Since the acceptable limit of deviation set by the IAEA for this absorbed dose work is ± 3%, it is clear that the overall deviations obtained were all satisfactory.
Fulltext Cosmetic and functional outcomes of two-stage hypospadias repair: an objective scoring evaluation and uroflowmetry

Hussein NS, Samat SB, Abdullah MA, Gohar MN

Turk J Urol, 2013 Jun;39(2):90-5.
PMID: 26328087 DOI: 10.5152/tud.2013.015

OBJECTIVE: The functional outcome following hypospadias repair is as important as the cosmetic outcome. Currently, structured scoring systems, patient questionnaires and evaluations of photographs and uroflowmetry are used to assess the results of hypospadias repair. In the present study, we assessed the outcomes of two-stage hypospadias repair using Hypospadias Objective Scoring Evaluation-HOSE and measures of uroflowmetry.
MATERIAL AND METHODS: Over a period of eight years, from January 1997 to December 2004, 126 hypospadias patients were treated, 90 of these patients received two-stage repairs and 36 patients received single-stage repairs. HOSE questionnaire and uroflowmetry data were obtained to evaluate the long-term outcome of the two-stage hypospadias repairs.
RESULTS: The age at the time of assessment ranged from 8 to 23 years-old, with a mean follow-up time of 39.78 months. Thirty-five patients had proximal hypospadias, and 20 had distal hypospadias. Of the 55 patients who received complete two-stage hypospadias repair and agreed to participate in the study, nineteen patients had acceptable HOSE scores and 36 patients had non-acceptable scores. The uroflow rates of 43 of the subjects were below the fifth percentile in three patients, equivocal (between the 5(th) and 25(th) percentile) in four patients and above the 25(th) percentile in 36 patients.
CONCLUSION: Two-stage repair is a suitable technique for all types of hypospadias with varying outcomes. HOSE and uroflowmetry are simple, easy, non-invasive and non-expensive tools for objectively assessing the long-term outcomes of hypospadias repair.
Malaysian participation in the IAEA/WHO postal TLD and postal ionisation chamber intercomparison programmes: analysis of results obtained during 1985-2008

Samat SB, Evans CJ, Kadni T, Dolah MT

Radiat Prot Dosimetry, 2009 Feb;133(3):186-91.
PMID: 19299478 DOI: 10.1093/rpd/ncp035

During the years 1985-2008, the Secondary Standards Dosimetry Laboratory of Malaysia (SSDL Malaysia) has participated 37 times in the IAEA/WHO intercomparison programmes. This paper reports an analysis of the intercomparison data and demonstrates that the quality of the SSDL calibration service is well within the limits required by IAEA.
Accurate measurement of exposure rate from a 60Co teletherapy source: deviations from the inverse-square law

Samat SB, Evans CJ, Kadni T, Dolah MT

Br J Radiol, 2000 Aug;73(872):867-77.
PMID: 11026863

A cylindrical gamma-ray 60Co source of activity alpha is predicted to produce an exposure rate X at a distance d in vacuum, given by X = gamma(T)(alpha/d2), where gamma(T) is the specific gamma-ray constant. It has been documented that this formula may be used to approximate X with an accuracy of 1% from a source of length l, provided that d/l > or = 5. It is shown that the formula is accurate to 0.1% under these conditions, provided that the distance is measured from the centre of the source. When absorption in the source and scattering in the collimator are considered, the position of the origin d = 0 can shift by a distance of the order of centimetres. Absorption in air between the source and the ionization chamber adds an exponential factor to the formula. It is shown that even when these modifications are included the discrepancy in the results, although generally less than 1%, is still large compared with the measurement errors. Some suggestions are made for the origin of this discrepancy.