Background Prostate biopsy remains an important surgical procedure in the diagnostic pathway for prostate cancer, but access to prostate biopsy service is poorly studied in the Nigerian population. While there has been a well-documented delay in patient presentation with prostate cancer in Nigeria, little is however known about how long patients wait to have a histological diagnosis of prostate cancer and start treatment after presenting at Nigerian hospitals. Method This was a descriptive retrospective study to document the specific duration of the various timelines in getting a diagnosis of prostate cancer at the Lagos State University Teaching Hospital, Ikeja, Nigeria. Results There were 270 patients. The mean age was 69.50 ± 8.03 years (range 45-90). The mean PSA at presentation was 563.2 ± 1879.2 ng/ml (range 2.05-15400), and the median PSA was 49.3 ng/ml. The median waiting times were (i) 10 days from referral to presentation; (ii) 30 days from presentation to biopsy; (iii) 24 days from biopsy to review of histology; (iv) 1 day from histology review to discussion/planning of treatment. The median overall waiting time from referral to treatment was 103 days. The mean time from presentation to biopsy was significantly shorter for patients with PSA of ≥50 ng/ml compared to those with PSA < 50 ng/ml. p = 0.048. Overall, the median time from biopsy to histology was significantly shorter for patients whose specimens were processed in private laboratories (17 days) compared to those whose specimens were processed at the teaching hospital laboratory (30 days), p ≤ 0.001. Conclusion There is a significant delay within the health care system in getting a prostate cancer diagnosis in the Nigerian population studied. The major points of the identified delay were the waiting time from patient presentation to having a biopsy done and the histology report waiting time.

Trace element investigation and its corresponding concentration level in selected tropical woods from western Nigeria was done using PIXE-particle induced X-ray emission methods. Fifteen selected tropical woods were analyzed and twenty-seventrace elements were identified and quantified. The identified trace elements are Na,Mg, Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Se, Br, Rb, Sr, Y, Zr, Ba, Pb and Bi. Calcium concentration were2835, 3195, 4923, 5608, 7770, 5110, 2743, 5092 and 3451ppm in samples 2, 5, 6, 10, 11, 12, 13, 14 and 15, respectively. Potassium recorded2838, 4811, 3184, and 2021ppm in samples 1, 3, 8 and 9, respectively. Silicon recorded5206ppm for sample 4 and 5253ppm for sample 7. Calcium and potassium were observed to have concentration level that is greater than 1000ppm in all the studied samples, hence it can be said that calcium and potassium are major trace element of wood. The concentrations of the elements identified have no immediate health concern on environment and human, therefore the studied tropical woodssafe for use as fuel and other purposes.

In this paper, investigation of the effect of Reynolds number, nanoparticle volume ratio, nanoparticle diameter and entrance temperature on the convective heat transfer and pressure drop of Al 2 O 3 /H 2 O nanofluid in turbulent flow through a straight pipe was carried out. The study employed a computational fluid dynamic approach using single-phase model and response surface methodology for the design of experiment. The Reynolds average Navier-Stokes equations and energy equation were solved using k- ε turbulent model. The central composite design method was used for the response-surface-methodology. Based on the number of variables and levels, the condition of 30 runs was defined and 30 simulations were performed. New models to evaluate the mean Nusselt number and pressure drop were obtained. Also, the result showed that all the four input variables are statistically significant to the pressure drop while three out of them are significant to the Nusslet number. Furthermore, sensitivity analysis carried out showed that the Reynolds number and volume fraction have a positive sensitivity to both the mean Nusselt number, and pressure drop, while the entrance temperature has negative sensitivities to both.

Bolus is a tissue equivalent material which is use in radiation therapy in order to eliminate skin sparing effect of higher energy photon beams that always reduce the surface dose. There are several commercially bolus material such as Superflab, Aquaplast and gels for use but literature have shown that they are expensive and are not readily available in developing countries. This work presents the fabrication of an alternative bolus for Cobalt-60 Teletherapy using two locally available materials (Beeswax and Petroleum jelly). Beeswax was liquefied at a temperature of 60°C followed by the addition of Petroleum jelly at ratio 3:1 by weight for proper molding and flexibility. In order to determine the depth of maximum dose, Thermoluminescent Dosimeter (TLD) chips were inserted in between ten bolus materials of thickness 0.5 cm that were arranged in layers and placed on a solid water phantom. This was then irradiated with Cobalt-60 radiation source using field size ranging from 5 cm x 5 cm to 10 cm x 10 cm field size. For all the field size, maximum absorbed dose was found to be at 0.5 cm depth. This depth of maximum dose was compared to two tissue equivalent materials in use in radiation therapy: water and Superflab for Cobalt-60 Teletherapy and found to be in agreement. The percentage dose deviation when compared with water for 1 cm, 2 cm, 3 cm, 4 cm and 5 cm were less than 2%. The flexibility of the bolus material and the analysis of the absorbed dose measured have shown that the fabricated bolus material of thickness 0.5 cm can be used as an alternative bolus material for Cobalt-60 Teletherapy.

Background: Nephrectomies are performed for various reasons ranging from benign to malignant renal diseases. The surgical approach for a nephrectomy also varies with location. In Nigeria and many other developing countries, the major technique of performing a nephrectomy is an open approach. Objective: The objective of the study was to evaluate the cases of nephrectomies performed over a 5-year period at the Lagos State University Teaching Hospital, Ikeja and compare the findings with those from other institutions in our region. Materials and Methods: This was a retrospective study. The clinical records of consecutive patients who had nephrectomies done over a 5-year period between January 2009 and December 2014 were reviewed. The data extracted from their record included age, sex, indication for nephrectomy, laterality (whether right or left), surgical approach, duration of surgery, the incidence of blood transfusion, histological findings and treatment outcome. Results: The records of a total of 40 patients were available. There were 16 males (40%) and 24 females (60%) with a M:F ratio of 1:1.5. The mean age was 44.75 ± 17.16 years (range: 3-70 years). The indication in the majority of the patients was renal malignancy (n = 30, 75%) while the remaining10 (25%) were benign cases ranging from non-functioning hydronephrotic kidneys from periureteric junction obstruction to staghorn calculi. A total of 25 cases (62.5%) were on the right, while 15 (37.5%) were on the left. The imaging study done for diagnosis was majorly an abdominopelvic CT scan in 32 patients (80%). Twenty-one patients (52.5%) had a flank approach, while 19 patients (47.5%) had an anterior approach for their surgery. The mean duration of surgery was140 ± 53.2 minutes (range 60-270 minutes). 27 patients (67.5%) were transfused perioperatively. The majority (n = 14, 46.7%) of the patients with renal malignancy had a histological diagnosis of the papillary variant of renal cell carcinoma. 32 patients (80%) were followed up for at least 3 years, while the rest were lost to follow up. The quantity of blood transfused correlated with the duration of the surgery. There was no perioperative mortality. Conclusion: Renal malignancies are the most common indication for nephrectomy in our centre. Though associated with a high transfusion rate, open nephrectomy (even when performed for a malignant condition) remains a safe procedure with a good outcome.

Introduction: The dose in computed tomography (CT) often approach or exceed the optimum levels, thereby increasing the probability of cancer induction. With wide application of this diagnostic test, it is expedient to determine the effective dose (ED) for each patient to estimate their cancer risk. This study was conducted to investigate the patient-specific dose (PSD) and cancer risk in CT examinations in Ondo, Nigeria. Material and Methods: The study was conducted on 160 patients undergoing eight most common types of CT examinations performed at the center, from December 5, 2015 to February 28, 2016. Body mass index (BMI) was calculated for each patient using demographic data, PSD was determined and estimation of the lifetime attributable risk (LAR) of cancer was accomplished using the Biologic Effects of Ionizing Radiation VII (2006) report phase 2 models. Results: From the results, radiation doses varied significantly within and between the types of CT examinations. The mean ED was 5.88±3.75 mSv in a range of 0.78-19.00 mSv. The mean PSD was 0.274±0.229 mSv/kgm-2 in a range of 0.024-1.555 mSv/kgm-2 and the mean LAR of cancer incidence was 0.04861±0.03996 Sv-1 in a range of 0.00004-0.21942 Sv-1. Conclusion: ED and PSD varied within and across the CT examinations. In this regard, the coefficients of variation of ED for abdominal, cranial, craniocervical, abdomen/pelvis, thoracic, thoracoabdominal, cervical spine, and pelvis were 5.7%, 6.6%, 3.9%, 8.9%,3.7%, 6.0%, 44.7%, and 19.2%, respectively. Accordingly, the coefficients of variation of PSD were 9.0%, 7.9%, 7.0%, 10.1%,5.6%,23.8%, 47.7%, and 14.2%.

In this study, we applied particle-induced X-ray emission (PIXE) spectroscopy to investigate the levels of trace elements in breast tissues and whole blood (cancerous and non-cancerous) of selected African women in Ile-Ife, Southwest Nigeria. Freeze-dried and homogenized specimens obtained through mastectomy from clinically diagnosed patients were made into 11-mm-diameter pellets. The pellets were irradiated with 2.5 MeV proton beam energy from a 1.7 MV 5SDH Tandem accelerator. The PIXE analytical system was calibrated with certified reference matrices of Bovine Liver and Animal Blood: NIST 1577a and IAEA-A-13, respectively. A total of 23 elements: Na, K, Ca, Cl, S, Al, P, Si, Zn, Pb, Br, Rb, Zr, Se, Sr, Mn, V, Ti, Cu, Fe, Ni, Cr, and Mg were detected. The results indicated that the levels were within 0.9-5288 and 0.6-2320 ppm in breast tissues and 0.3-17228 and 2.0-2475 ppm in the whole blood of cancerous and non-cancerous subjects, respectively. At the .05 level of significance, significant differences exist between these levels in the cancerous and non-cancerous breast tissues (t = 0.008) as well as the whole blood (t = 0.041). The results gave the baseline concentration of the observed trace elements in the normal and malignant subjects and indicated PIXE as a powerful tool for such investigation.

Introduction: Urolithiasis has afflicted humans since centuries dating back to 4000BC, with the disease prevalence differing in various parts of the world.Contrary to earlier studies that depicted urinary stone disease as rare in Nigeria, recent reports have shown an increasing incidence.We aim to document the pattern and management of urinary tract calculi seen at the Lagos State University Teaching Hospital, Ikeja, Nigeria.Patients and Methods: We retrospectively reviewed the cases of urolithiasis managed at Lagos State University Teaching Hospital, Ikeja, Nigeria between January 2012 and December 2016.Variables analyzed were patients' age, gender, presenting symptoms, investigations and modalities of treatment.Results: The clinical records of a total of seventy-six patients treated for urinary stone disease within the 5-year study period were available for review.The ages of the patients ranged from 2 years to 84 years with a mean age of 49.13 ± 16.27 years.The male to female ratio was 1.8:1.While the urinary bladder was the commonest site of the stone amongst our patients (n=37, 48.7%), 4 (5.3%) were found at multiple sites.All the patients had abdominal ultrasound and 57.9% had, in addition, a computerized tomography (CT) urography.Majority, (53.9%) were treated by open surgery.There was no statistically significant impact of gender on disease presentation (P=0.167) or treatment (P=0.8381).However the patients who had surgical treatment were significantly older than those who were treated conservatively (P=0.033).Conclusion: Urolithiasis in our region has become more common, mimicking the increasing prevalence reported in the West.Most of the cases of urinary tract stones are still successfully managed by open surgery and thus open stone surgery should be considered as a valid alternative to endourologic management techniques in resource poor regions lacking endoscopic facilities.

Aims: The aim of this research work is to estimate the organ dose distribution and the associated radiation induced cancer risk for some commonly performed Computerized Tomography (CT) examinations in a tertiary medical facility in South Nigeria. Study Design: The study was designed to estimate the radiological implications of radiation dose that the paediatric patients were exposed to during routine CT examinations. Place and Duration of Study: Department of Radiology, Obafemi Awolowo University Teaching Hospital Complex, (OAUTHC), Ile-Ife, Nigeria, between August 16, 2011 to August 15 2012. Methodology: Well calibrated thermoluminescent dosimeters (LiF-100) were attached to the skin of paediatric patients such as skull, chest, abdomen, and pelvic in the path of the primary X-ray beam to determine radiation exposure during CT examination. The effective dose was calculated from the equivalent dose obtained from OAUTHC, and the cancer risk associated was estimated by multiply age-dependent lifetime cancer mortality risk (per unit dose) with estimated age-dependent doses produced by various CT examinations. Results: Out of 258 paediatric patients scanned the equivalent dose measured for abdominal CT scan ranged from 23.49 - 55. 26 mSv; skull CT scan ranged from 10.07 – 69.94 mSv and chest CT scan ranged from 8.60 – 31.94 mSv. The peak tube voltage (kVp) used range from 80 – 140 while the exposure current-time product (mA) range from 30 – 300. The abdominal CT scan had the highest cancer risk ranging from digestive 37.5% to lung cancer risk of 0.4%. The risks estimated in this work were higher than the ICRP recommended value. Reducing the millampere-second setting of the equipment for paediatric without significant loss of radiological information will reduce this risk. Conclusion: In this study the estimated cancer risk to paediatric patients undergoing CT is high. This is in keeping with findings in a previous study thus emphasizing the need to standardize and optimize radiation dose in paediatric patients undergoing CT in Nigeria so as to keep cancer risk at the minimum.

The fast-neutron shielding behaviour (FNSB) of two clay-materials (Ball clay and Kaolin)of Southwestern Nigeria (7.49 degrees N, 4.55 degrees E) have been investigated using effective removal cross section, Sigma(R) (cm(-1)), mass removal cross section, Sigma(R/rho) (cm(2)g(-1)) and Mean free path, lambda (cm). These parameters decide neutron shielding behaviour of any material. A computer program - WinNC-Toolkit has been used for computation of these parameters. The toolkit evaluates these parameters by using elemental compositions and densities of samples. The proficiency of WinNC-Toolkit code was probe by using MCNPX and GEANT4 to model fast neutron transmission of the samples under narrow beam geometry, intending to represent the actual experimental setup. Direct calculation of effective removal cross section (cm(-1)) of the samples was also carried out. The results from each of the methods for each types of the studied clay-materials (Ball clay and Kaolin) shows similar trend. The trend might be the fingerprint of water content retained in each of the samples being baked at different temperature. The compositions of each sample have been obtained by Particle-Induced X-ray Emission (PIXE) technique (Tandem Pelletron Accelerator: 1.7 MV, Model 5SDH). The FNSB of the selected clay-materials have been compared with standard concrete. The cognizance of various factors such as availability, thermo-chemical stability and water retaining ability by the clay-samples can be analyzed for efficacy of the material for their FNSB. (C) 2019 Korean Nuclear Society, Published by Elsevier Korea LLC.

Background: Metastatic Castration Resistant Prostate Cancer (mCRPC) is invariably a terminal disease. Though international guidelines exist on mCRPC management, there are varied practices regarding the sequencing of limited available treatment options locally. Objectives: To describe the treatment sequence and outcome of management of mCRPC at the Lagos State University Teaching Hospital, Ikeja over a 4 year period. Methods: This was a retrospective study in which the clinical records of all patients diagnosed with mCRPC at the Lagos State University Teaching Hospital, Nigeria between June 2012 and June 2016 were retrieved and analyzed. Results: There were 30 patients with mCRPC within the study period. The mean age of the patients was 69years. There was a biochemical confirmation of castration resistance in most of the patients (86.7%). The mean serum Prostate Specific Antigen (PSA) at the time of diagnosis was 771ng/ml and the mean Gleason Score was 8. Antiandrogen withdrawal/substitution was the most common first line of management (72.4%), while the use of docetaxel based chemotherapy (36.8%) was the most common second line treatment. Only 13.3% were treated with the newer agents abiraterone and enzalutamide. Almost half of the patients (46.7%) needed additional treatment with radiotherapy and/or zoledronic acid for symptomatic osseous metastases. Antiandrogen withdrawal/substitution was not significantly associated with increased risk of death at 18 months. Conclusion: Appropriate optimization and sequencing of the limited available treatment options for mCRPC are vital to a satisfactory outcome in a resource poor setting. Antiandrogen withdrawal/substitution should be a consideration in the management of mCRPC patients in resource poor environments.

Background: Though prostate biopsy is generally a safe procedure, it can be associated with complications. It is important to document the complication rates and identify potential risk factors for these complications. The aim of this study was therefore to investigate the complication rates following prostate biopsy at the Lagos State University Teaching Hospital Ikeja Lagos Nigeria over a 5 year period from January 2012 to December 2016. Patients and Methods: This was a retrospective study in which the clinical records of all the patients who had prostate biopsy at the Lagos State University Teaching Hospital Ikeja, Lagos Nigeria over a 5 year period between January 2012 and December 2016 were retrieved and analyzed. Results: The clinical records of a total of 258 patients were available for review. The mean age was 68.2years (range 45 to 81years). The mean and median PSA values were 560ng/ml and 57ng/ml respectively (range 2.05 to 15,400ng/ml). The prostate biopsy was transrectal and digitally guided in all cases. All the patients had empirical intravenous prophylactic antibiotics with intravenous ciprofloxacin 500mg stat and were discharged on oral ciprofloxacin 500mg bd and oral metronidazole 400mg tds for one week. All the patients had a caudal block. One hundred and seventeen (45.3%) had a comorbidity. The mean prostate size was 109gms (range 16 – 146gms). The size of the trucut needle used was size 16 in 121 patients (46.9%) and size 18 in 125 patients (48.4%). The mean number of biopsy cores taken was 10 (range 4 to 15). The histological diagnosis was carcinoma of the prostate in 154 patients (59.7%) and benign prostatic hyperplasia in 100 patients (38.8%). Twenty four patients (9.3%) had complications. The complications were sepsis (3.1%), rectal bleeding (2.3%), haematuria (2.3%) and acute urinary retention (1.6%). Thirteen patients needed hospitalization (5%). There was no mortality. The incidence of sepsis was statistically significantly higher with increasing the number of cores taken (p=0.000), but there was no significant difference in the incidence of sepsis with the size of the trucut needle used (p= 0.299) or the presence of morbidity (p = 0.503). Conclusion: Though the complication rates following prostate biopsy remain low, increasing number of prostate cores taken is a risk factor for adverse events. We therefore recommend reducing the number of prostate cores taken in patients with advanced prostate cancer with high tumour volume in order to further reduce the risk of prostate biopsy complications in our environment.

In this study, risk of exposure to adult patients in some common radiological procedures was estimated at selected diagnostic centers in Lagos State, Nigeria using estimated average effective doses. The results showed that pelvis lateral (LAT) examination with the lowest estimated mean effective dose level (2.61) recorded the highest probability of cancer incidence and mortality occurrences, while lumbar anteroposterior (AP) had the lowest (3.61). A high sum total of probability of fatal cancers and the total weighted probability of non-fatal cancer in a single exposure to low-dose ionizing radiation were recorded in pelvic procedure among others. Also, a high-percentage mortality increase of solid cancers was recorded in chest PA examination (53.7%), while the lowest was in lumbar spine radiography (with lumbar AP = 0.14%, lumbar LAT = 0.15%). The data obtained suggested the possibility of having higher percentage mortality and cancer-related incidence in the chest.

Particle Induced X-ray Emission technique has been employed in the determination of essential and trace elements in Moringa oleifera leaves and seeds from two sites in South Western Nigeria. Sixteen elements (Na, Mg, Al, Si, P, S, Cl, K, Ca, Mn, Fe, Cu, Zn, Rb, Sr and Ba) were detected and quantified. Rb and Ba were detected only in the leaves, while Al and Na were found only in the seeds. The leaves have higher concentration of K (17053.90±56.28 ppm) whereas the element with highest concentration in the seeds was S (5474±44.35 ppm). The results show that the plant contains many elements of vital importance for human metabolism, diseases prevention and healing. Keywords: Moringa oleifera , leaves, seeds and elements

High-energy beta emitters (yttrium-90, strontium-89 and phosphorus-32) are nowadays increasingly used in therapeutic nuclear medicine. Beta particles and bremsstrahlung (photons produced when beta particles interact with materials) are harmful and should be shielded in order to protect the personnel and public from their harmful effects. This work determined the radiation yield, effective atomic number and range associated with the interaction of beta particles with a transparent xBi(2)O(3)-30B(2)O(3) (70-x)TeO2 glass system (where x = 40, 50, 60 and 70 mol%) using the ESTAR database and programme; and other relevant equations. The properties of the studied glass systems were compared with transparent lead glass, which is unwanted in the medical settings because of lead's toxicity. The result of this work showed that the studied glasses are suitable for use in making vials, syringes and other transparent materials, necessary for shielding high-energy beta particles. All the studied glass systems can replace lead glass.

The elemental composition analysis and its concentration levels in percentage were done on several wood samples using Rutherford Backscattering Spectrometry (RBS) of Ion Beam Analytical (IBA) methods. A total of twenty seven (15) tropical hardwoods from south western Nigerian environment were analyzed and six (6) major elements (C, O, N, Na, S, Cl) were identified. Carbon has the highest percentage constituents, ranging from 58.30% to 73.46%, in all the samples with sample 4 (Albizia gummifera) having the highest concentration of carbon as 73.46% and sample 7 (Anadelphia afzeliana) having the least carbon quantity as 58.30%.Nitrogen N ranged from 1.21% - 7.76%, Oxygen O 17.96% - 34.83%, Sodium Na 0.36% - 1.08%, Chlorine Cl 0.11% - 0.46%, and Sulfur S 0.13% to 0.59%. C was above the overall wood estimated constituent 50%, O below estimated value of 40%. Cl and S were within estimated range as trace element percentage range. The variation in elemental composition of wood used in the experiment shows that wood species have thesame elemental compositional trend as some human tissues and could be harness for use as tissues equivalent material for application in medical radiation dosimetry.

The low temperature peak (PI) of natural fluorite which occurs at 94oC at the heating rate of β = 1 Cs-1exhibits complexity both in terms of shape and position as the absorbed dose is varied. The short lifetime of this peak makes it a good case for testing the existing thermoluminescence kinetic models. In this paper, the kinetic parameters of PI, namely the activation energy, EA , the frequency factor, S, and the order of kinetics, b, have been evaluated using general order kinetics. Fluorite samples were irradiated with a low dose-rate (40 μGys-1 ) β- irradiation source to a test dose of 1.2 mGy and the heating rates of β = 1,3 and 5o Cs were considered, in order to minimize the effect of temperature lag. The role of thermal quenching (W) was investigated by evaluating the activation energy using the initial rise (IR) method for each of the heating rates. The obtained values of kinetic parameters are EA = (1.31 ± 0.06) eV and S = (8.34 ± 1.00) × 1016 s-1 while values of b ranging from above 1.0 up to 1.4 were in good agreement. The value of W = (0.30 ± 0.04) eV was obtained for the thermal quenching function and its contribution was found to be most significant at the heating rate of β = 5so C s-1 .Keywords: low-dose β-irradiation, first peak of natural fluorite, general-order kinetics, thermal quenching function, peak lifetime.

The gamma radiation shielding capability (GRSC) of two clay-materials (Ball clay and Kaolin)of Southwestern Nigeria (7.49 degrees N, 4.55 degrees E) have been investigated by determine theoretically and experimentally the mass attenuation coefficient, mu/rho (cm(2) g(-1)) of the clay materials at photon energies of 609.31,1120.29, 1173.20, 1238.11, 1332.50 and 1764.49 keV emitted from Bi-214 ore and Co-60 point source. The mass attenuation coefficients were theoretically evaluated using the elemental compositions of the claymaterials obtained by Particle-Induced X-ray Emission (PIXE) elemental analysis technique as input data for WinXCom software. While gamma ray transmission experiment using Hyper Pure Germanium (HPGe) spectrometer detector to experimentally determine the mass attenuation coefficients, mu/rho (cm(2) g(-1)) of the samples. The experimental results are in good agreement with the theoretical calculations of WinXCom software. Linear attenuation coefficient (mu), half value layer (HVL) and mean free path (MFP) were also evaluated using the obtained mu/rho values for the investigated samples. The GRSC of the selected clay-materials have been compared with other studied shielding materials. The cognizance of various factors such as availability, thermo-chemical stability and water retaining ability by the claysamples can be analyzed for efficacy of the material for their GRSC. (C) 2018 Korean Nuclear Society, Published by Elsevier Korea LLC.

Thermoluminescent (TL) characteristics of clay samples from Ijero-Ekiti and Isan-Ekiti, Ekiti State, Nigeria were studied for application in retrospective dosimetry. In order to increase the potentials of the clay material for relevant radiation measurement applications, characteristic glow curves of samples from the clay deposits have been obtained using a Victoreen (2800M) TL reader and the TL properties subsequently examined. The variable heating rate method was used to determine the glow peak shape and intensity by estimating the activation energy or trap depth, E and the frequency factor, S. Most samples demonstrated the dependence of their glow curve on the heating rate, with the peak temperature, Tm increasing with the heating rate. These glow peaks were noted to be a complex trapping system, consisting of several overlapping first order peaks and each with different TL behaviour, except for certain samples, which showed independence of peak temperature with dose. While recommending further heating protocol to isolate each peak for the calculation of other kinetic parameters, we present an approximate 0.29–0.84eV for E and 3.7×101 to 4.0×106s−1 for S. Though the samples with the TL dosimetric property of increased peak intensity with increasing excitation dose could be considered for TL applications, the reduction in TL intensity must be considered for high heating rates applications.

The term "quarry products" comprises different natural rocks with different mineral contents, crushed into various sizes at quarries. The concentrations of the naturally occurring radionuclides K-40, U-238 and Th-232 in quarry products from southwest Nigeria have been measured using gamma ray spectrometry. The gamma absorbed dose rate (D-R), radium equivalent activity (Ra-eq), annual effective dose (A(d)), activity concentration index (I), external radiation index (H-ex) and internal radiation hazard index (H-in) associated with the radionuclides are evaluated in order to assess the radiation hazard of quarry products used as building materials. The results showed that a few of the calculated radiological parameters are higher than permissible limit, hence, may pose a radiological hazard when used as building materials.All the radiological variables above were subjected to correlation analysis to determine the similarities and correlations among various samples. The data sets consist of 10 measured variables. The principal component Analysis (PCA) yields a two component representation of the acquired data, in which 93.3% of the total variance is explained. Copyright (C) 2015, The Egyptian Society of Radiation Sciences and Applications. Production and hosting by Elsevier B.V.