International Journal of Radiation Research
Volume:12 Issue: 3, Jul 2014

There is a rapid increase worldwide in the consumption of mineral waters which may contain different level of radioactive elements, especially 226Ra, in addition to varying amounts of beneficial salts. Therefore, a comprehensive study was planned and carried out in order to determine concentration of 226Ra natural radionuclide in bottled mineral waters that commercially available in Marmara Region of Turkey. The method used for 226Ra concentration analysis bases on the measurement of Radon (222Rn) coming from 226Ra dissolved in the water. The measurements were performed using RAD 7, a solid state α detector, with RAD H2O accessory manufactured by DURRIDGE COMPANY Inc. The 226Ra concentration in mineral waters was found to vary from <0.074 to 0.625 Bql-1 with an average value of 0.267 Bql-1.The committed effective doses due to ingestion of 226Ra from the one year consumption of these waters were estimated to range from 10.8 to 90 µSvy-1, from 9 to 75 µSvy-1 and from 3.15 to 26.25 µSvy-1, for infants, children and adults, respectively. The results obtained in this study indicate that the committed effective doses are below the WHO (World Health Organization) recommended reference level of 100 µSvy-1.

Ovarian immature teratoma is a very rare type of tumor associated with a high relapse rate and mortality. Correspondingly, early diagnosis is important for effective treatment. The goal of this study was to retrospectively analyze the ultrasound characteristics of 11 cases of immature teratomas. Between January 2002 and December 2010, 11 patients were diagnosed with pathologically confirmed immature teratomas. Patients enrolled in this study underwent a transabdominal ultrasound examination prior to surgery. Tumor size, shape, internal echo, calcification, cystic degeneration, and blood flow for each immature teratoma were analyzed. Levels of alpha fetal protein (αFP) were also evaluated. The average tumor size was 8 cm (range, 4–13). Echo patterns obtained included mixed echo (n = 7), solid echo (n = 2), and cystic echo (n = 2). Coarse calcifications were detected in five cases, while blood flow signal was detected in one case, and ascites were detected in three cases. Only one case had elevated levels of αFP. Ultrasound imaging of immature teratomas detected large tumors that were predominantly involved mixed-echo masses, cystic degeneration, and coarse calcification on the cavity wall. In some cases, blood flow signal was detected in the mass and ascites were present in the abdominal cavity.

Most of the cytogenetic dosimetry, except Premature Chromosome Condensation assay, saturates at 6 Gy. Present studies are aimed to assess feasibility of simple CB-MN assay for prescreening of high dose accidental exposures. Human peripheral blood lymphocytes from two donors were gamma irradiated to different doses ranging from 0-15Gy, cultured for 72 h. Cytochalasin-B was added to the cultures at 44 h. Slides were analyzed for frequency of Mononucleated cells (MNC), ratio of Tri/Quadra nucleated cells, micronuclei (MN) yield in MN positive cells, mitotic bridges and apoptosis. At 5 Gy 67% Mononucleated cells, 0.22% apoptotic cells and 1.76% mitotic bridges were observed. Micronuclei yield in MN positive binucleated cells was found to be 1.43±0.04. At 8Gy 96.63% Mononucleated cells, 22.64% apoptotic cells and 3.8% mitotic bridges were observed. Micronuclei yield in MN positive binucleated cells was found to be 2.18±0.18. At 15 Gy, 99.6% of the cells were Mononucleated and 0.38% was binucleated and MN yield was 2.9 ±0. The total number of MN in MN positive cells increases with increasing radiation doses. All the three indicators number of MN in all binucleated cells (BNC), number of MN /MN positive binucleated cells and the nuclear division index (NDI) can serve as good biomarkers for biodosimetry at high doses. Although the frequency of mitotic bridges and apoptotic bodies increases with dose, there is no consistent difference between various doses. Thus the CBMN + NDI assay can be a biodosimetry method at high doses.

Finding a suitable method for rapid, accurate and reliable estimation of absorbed dose has high priority in management of the radiation exposed persons. Shortly after radiation exposure, apoptosis is a major detriment in proliferative tissues such as the hematopoietic system. Therefore, quantification of apoptosis in these tissues could be useful for rapid estimation of radiation exposure. Annexin V (ANX) is considered as a biological probe for detection of apoptotic cells. The aim of the present study is to investigate the potential suitability of apoptosis quantification for estimation of radiation exposure. In order to determine the biological distribution of ANX within the mice body after radiation exposure, mice whole body irradiated with 2, 4, 6 and 8 Gy (60Co gamma rays). Ten hours later, ANX conjugated with super paramagnetic iron oxide nanoparticles (SPIO-ANX) was administered intravenously and magnetic resonance imaging was conducted 3 hours later. Average signal intensities in the regions of interest (ROIs) of the femur bone marrow, liver and testis were calculated and normalized to parafemoral muscle signals. SPIO-ANX accumulated in bone marrow of irradiated groups and significantly decreased the normalized mean of signal intensity for bone marrow in comparison with control group (p< 0.01). Tracing and quantification of SPIO-ANX in bone marrow can be used as an indicator for radiation exposure. However, development and optimization of the assay are necessary for discrimination between different radiation doses.

Radiation-induced lung injury is a refractory side effect in lung cancer radiotherapy, the mechanism still remains unclear, hence an appropriate animal mode may become useful to investigate it. 50 female Wistar rats were randomly divided into 5 groups, average 10 rats/cage: A. control group; B. 3Gy×10f; C. 6Gy×5f; D. 12.5Gy×1f; E.15.3Gy×1f. By different doses of radiation to the right lung of rats under American Varian linear accelerator, all the rats were executed at 30days after irradiation, lung tissues were collected to observe the pathological changes by HE staining, and additional lung tissues were extracted mRNA to measure gene expression of TNF-a and IL-18 by qRT-PCR. In contrast to the control group, congestion, gore, edema, broadening alveolar interval and the bulla can be observed after irradiation. 3Gy×10f radiation led to most rat death because of frequent anaesthesia. 12.5Gy×1f radiation induced mild lung injury. 6Gy×5f and 15.3Gy×1f radiation induced remarkable lung injury. However, 15.3Gy×1f was seldom adopted in clinical settings. The measurement of cytokine variation by qRT-PCR also indicated that 6Gy×5f radiation stimulated the most obvious elevation of IL-18, while 15.3Gy×1f radiation elevated TNF-a most. A rat model of radiation-induced lung injury was appropriately established, 6Gy×5f radiation was the most suitable radiation method for establishing this rat model.

Vitamin D, especially its most active metabolite 1,25-dihydroxyvitamin D₃(Vit D) is essential in regulating a wide variety of biologic processes, such as regulating mesangial cell activation. The objective of this study was to assess the histopathological changes of effectiveness of Vit D as a protective agent against radiation induced lung injury. Eighteen Wistar rats were divided into three groups: control group (group 1:4 rats), irradiation alone group (group 2:7 rats) and irradiation+vit D (group 3:7 rats). Rats in group 2 and 3 were exposed to 20 Gy radiations to the right lung in a Co60 radiotherapy machine under general anesthesia. Additionally, rats in group 3 received Vit D at a single dose of 0.2 mcg injected IM 2 hours before exposure to irradiation. Rats were sacrificed and lungs were dissected fifty days after post-irradiation. Myofibroblasts and vitamin D₃receptors (VDR) in extracted lungs were stained by immunohistochemistry using alpha-smooth muscle actin (SMA) and VDR antibodies. Blinded histological evaluation was performed to assess lung injury. Lung injury was assessed by the acute lung injury score and myofibroblastic differentiation score. Acute lung injury scores and myofibroblastic differentiation scores were significantly lower in the radiation+vit D group compared to irradiation alone group (p=0.001 and p=0.001, respectively). This study indicates that administration of vit D plays a protective role against acute lung injury through blocking myofibroblastic differentiation.

This research was conducted to evaluate the potential benefits of zinc sulphate in the prevention of radiation induced mucositis in patients who are being treated for head and neck cancers. Forty patients with proven cancers of head and neck were randomly divided into 2 equal groups that either received zinc sulphate or placebo (control group). Patients who received curative radiotherapy or chemoradiotherapy were instructed to take zinc sulphate capsules (30 mg) daily at 8 hours interval. They were to begin 10 days before the start of treatment and continued until 2 weeks after completing the schedule. Mucositis was evaluated weekly according to the Oral Mucositis Assessment Scale (OMAS). In both groups (zinc and control) mucositis was evident during the first week but its prevalence was 40% and 70.5% in the zinc and placebo groups respectively at the end of this period. This difference was significant (p<0.0001). The mean severity of oropharyngeal mucositis increased after commencement of radiotherapy and reached to maximum intensity in the 4th week. Control group showed higher severity (p<0.0001). In comparison with the placebo group, the mucositis score of OMAS in the zinc group was lower until at 2 weeks after end of the treatment (p=0.0001). The present study shows that Zinc sulfate is effective in reducing the severity of radiation induced oropharyngeal mucositis. In addition, it delays the development of mucositis and may be used at a lower dose (30 mg 3 times daily) with the same benefit but fewer side effects.

The aim of this study was to evaluate the reduction in excision cavity volume (ECV) during the whole breast radiotherapy (WBRT). The delineating of reduced cavity volume on secondary CT (computed tomography) might decrease the field size of boost plan. Twenty patients were treated having breast conservative surgery. At first, primary CT simulation (CT-1) was done prior to WBRT. Treatment planning was performed by a 3D treatment planning system. A CT-2 was performed after WBRT. Then the excision cavity was contoured on CT-1 and CT-2 for each patient. Boost irradiation was planned on both ECV-1 and ECV-2. In Comparison of CT-1 and CT-2: The contoured volumes for ECV-1 and ECV-2 were on average of 42.9 cm3and 23.4 cm3, respectively (p< 0.002). The ECV-2 was reduced in 85% of the patients. Patients with ECV-1 greater than the mean value of ECV-1 (ECV-1> 35.5 cm3) had more reduction in ECV-2 than patient with ECV-1 smaller than the mean value (p < 0.000). The volume of normal breast tissue on CT-2 was decreased from the volume of CT-1 (p< 0.03). A significant reduction in excision cavity volume was shown during WBRT. This volume reduction made smaller sizes of boost field and remaining breast received lower doses. The reduction was more significant in patient with primary large ECV. The Secondary CT for boost planning is suggested for patients with larger cavities after WBRT.

Physical wedges are still widely used as beam modifiers in external beam radiotherapy. However the presence of them in the beam trace may cause beam hardening which may not be considered in many treatment planning systems. The aim of this study is to investigate the beam hardening effect generated by physical wedges via different beam quality indexes as photon spectrum, half value layer, mean energy and tissue–phantom ratio. The effect of physical wedges on the photon beam quality of a 6-18MV Varian 2100C/D accelerator was studied with the BEAMnrc Monte Carlo code. Good agreements were obtained between measured and calculated depth doses and beam profiles for open and wedged photon beams at both energies. It was noticed that for 6 MV photon beams, physical wedges have more significant effects on beam quality than for 18 MV. Also it was obtained that at 18 MV photon beam as the wedge angle increased, the effect of wedge on beam quality becomes reversed and beam softening occurred. According to these results, it is recommended that beam hardening and softening of physical wedges should be considered in treatment planning systems in order to increase the accuracy in dose delivery.

Electronic portal imaging devices (EPIDs) play an important role in radiation therapy portal imaging, geometric and dosimetric verifications. A successful utilization of EPIDs for imaging and dosimetric purposes requires a reliable quality control process routine to be carried out regularly. In this study, two in-house phantoms were developed and analyzed for implementation in a quality assurance program for dosimetry purposes. An amorphous silicon (a-Si) imager (OptiVue500) was used. A low contrast resolution phantom and an image quality phantom were constructed and implemented. Low contrast resolution of the EPID was evaluated by counting the number of holes detectable in the image of phantom using human observers and a software. The image quality phantom was used for modulation transfer function, contrast to noise ratio and noise level evaluations. This phantom contains five sets of high-contrast rectangular bar patterns of variable spatial frequencies and six uniform regions. Although the manual low contrast resolution method was observer-dependent and insensitive to artifacts, the automatic method was robust and fully objective but sensitive to artifacts. The critical frequency values for 6 and 18 MV were 0.3558±0.006 lp/mm and 0.2707±0.006 lp/mm respectively. The contrast-to-noise ratio was found to be ~ 240% higher for 6 MV compared to 18 MV. The developed phantoms provide a convenient process for periodic performance of an EPID. These phantoms are independent of the EPID system and provide robust tools for continuous monitoring of image quality parameters as well as dosimetric parameters.

The purpose of this project was to derive the brachytherapy dosimetric functions described by American Association of Physicists in Medicine (AAPM) TG-43 U1 based on high dose rate 192I sources. The method utilized included both simulation of the designed Polymethyl methacrylate (PMMA) phantom using the Monte Carlo of MCNP4C and benchmarking of the simulation with thermoluminescent (TL) dosimeters. The obtained results for the radial dose function and anisotropy function showed nominal errors of less than 3% between TL measurements and the MCNP4C results. It may be concluded that due to small observed errors and the large uncertainty associated with the high dose gradients near the source point the simulation results can be used for dose estimation.

The aims of the study are to determine the radioactivity concentrations of 226Ra, 238U, 232Th and 40K in vegetables of a recently found high background radiation area of south-eastern part of Bangladesh and to detect the radiological risks to human from intake of these vegetables. 10 plant samples were collected randomly from different locations of the study area. The radio-nuclides in papaya were measured by direct γ-ray spectrometry using HPGe detector. The average activity concentrations of 226Ra, 238U, 232Th and 40K in papaya samples were 80.95±13.61, 64.77±38.47, 83.53±20.50 and 1691.45±244.98 Bq kg-1 respectively. The annual effective ingestion dose due to intake of papaya was 1.1 mSv Y-1. The concentrations of radio-nuclides in the papaya samples found in present study were higher than the world average values suggested by the UNSCEAR. The annual effective ingestion dose was found 3.8 times higher than total exposure per person resulting from the ingestion of terrestrial radioisotopes.

High density concrete is extensively used for efficient radiation attenuation in radiotherapy rooms and nuclear reactors. Over the past eight years, some efficient galena-based concrete samples for shielding X or gamma rays was produced. The goal of this study was to produce a novel high density concrete against neutron and photon radiations using tourmaline and galena. Attenuation of gamma photons was measured using a Farmer type ionization chamber with a standard 60Co buildup cap on a Theratron 60Co therapy unit. Neutron shielding characteristics were measured by using an Am-Be source. The MCNP4C radiation transport computer code was used to investigate the effects of various shield thicknesses on the attenuation of gamma-ray photons and neutrons. The concrete samples had a density of 4.0- 4.2 g/cm3. The compressive strength was 326 - 560 kg/cm2. The calculated value for Half Value Layer (HVL) of the tourmaline-galena concrete samples for 60Co gamma rays was 2.72 cm, which is much less than that of ordinary concrete (6.0 cm). The MC-derived HVL for photons with the same energy was 2.77 cm, which is in a good agreement with the experimental data. Moreover, ToGa concrete had up to 10 times greater neutron attenuation compared to that of the reference concrete. Tourmalin-Galena Concrete opens a new horizon in economic and efficient gamma/neutron shielding in high-energy radiotherapy bunkers, nuclear power plants, and shielding of radioactive sources.