Exposure to radiofrequency radiation emitted from mobile phone jammers adversely affects the quality of human sperm

Background: The health effect of rapidly increasing everyday exposure of humans to radiofrequency radiation is a major global concern. Mobile phone jammers prevent the mobile phones from receiving signals from base stations by interfering with authorized mobile carriers' services. In spite of the fact that mobile jammer use is illegal, they are occasionally used in offices, shrines, conference rooms and cinemas. The purpose of this study was to investigate the biological effects of short term exposure of human sperm to radiofrequency radiation emitted from a commercial mobile phone jammer

Materials and Methods: Fresh semen samples were obtained by masturbation from 50 healthy donors who had referred with their wives to Infertility Treatment Center at the Mother and Child Hospital, Shiraz University of Medical Sciences. Female problem was diagnosed as the reason for infertility in these couples. The semen sample of each participant was divided into 4 aliquots. The first aliquot was subjected to swim-up and exposed to jammer radiation. The second aliquot was not subjected to swim-up but was exposed to jammer radiation. The third and fourth aliquots were not exposed to jammer radiation but only the 3rd aliquot was subjected to swim-up

Results: Semen samples exposed to radiofrequency radiation showed a significant decrease in sperm motility and increase in DNA fragmentation

Conclusion: Electromagnetic radiation in radiofrequency range emitted from mobile phone jammers may lead to decreased motility and increased DNA fragmentation in human semen. It can be concluded that mobile phone jamming might exert adverse reproductive health effects

Radiation attenuation properties of shields containing micro and Nano WO3 in diagnostic X-ray energy range

Background: It has recently been shown that the particle size of materials used for radiation shielding can affect the magnitude of radiation attenuation. Over the past years, application of nano-structured materials in radiation shielding has attracted attention world-wide. The purpose of this study was to investigate the shielding properties of the lead-free shields containing micro and nano-sized WO3 against low energy x-rays. Materials and Methods: The radiation shields were constructed using nano and micro WO3 particles incorporated into an EPVC polymer matrix. The attenuation coefficients of the designed shields were evaluated for low energy x-rays [diagnostic radiology energy range]. Results: The results indicate that nano-structured WO3/PVC shields have higher photon attenuation properties compared to those of the micro-sized samples. Conclusion: Our experiment clearly shows that the smaller size of nano-structured WO3 particles can guarantee a better radiation shielding property. However, it is too early to draw any conclusion on the possible mechanisms of enhanced attenuation of nano-sized WO3 particles

Increased Mercury release due to exposure to electromagnetic radiation as a limiting factor for using dental amalgam

Background: although it is one of the most toxic nonradioactive elements, mercury is widely used in dental amalgam. Mercury is a toxic element which can damage various organs such as central nervous system, renal, respiratory and hematologic systems. The adverse health impacts associated to exposure to some common sources of electromagnetic fields including laptop computers, mobile phones, MRI and mobile phone jammers have been evaluated by our laboratory in our previous investigations. In this study, we aimed to evaluate the effect of X ray exposure on microleakage of amalgam restoration

Materials and Methods: standardized class V cavities were prepared on the buccal surfaces of 46 non-carious freshly extracted human premolars. The teeth were randomly divided into experimental and control groups. Experimental group were exposed to X-ray using an intraoral radiography machine at 60 kVp, 0.1 s, 7 mA with 2.5 mm Al total filtration. The absorbed dose was 245.0 +/- 0.5 microGy. All specimens were placed in 2 % basic fuchsin solution for 24 hours. Then the specimens were sectioned and microleakage was assessed according to dye penetration using a stereomicroscope. Statistical analysis was performed with the Mann-Whitney U-test

Results: microleakage was significantly higher in the X-ray exposed teeth compared to those of the non-irradiated samples

Conclusion: the results of the present study suggest that X-ray exposure increased microleakage of amalgam restorations

Design and fabrication of high density borated polyethylene nanocomposites as a neutron shield

Background: polyethylene composites including boron can be used as an effective neutron shield. Our investigation focuses on manufacturing borated polyethylene nano-composite. The purpose of this study is to design a radiation shield for use in both neutron and gamma fields

Materials and Methods: borated polyethylene shields containing 2%, and 5% weight percentage of Boron nano-particles were constructed and their neutron attenuation was compared with pure polyethylene. Polycarbonate films were used to find the attenuation of Am-Be neutrons after passing the shields. Mechanical properties of the shields were finally compared

Results: mean [+/- SD] number of alpha tracks induced by neutrons passing through the shields, were found to be 1.0488×10[3]+/-128.98, 1.1972×10[3]+/-289.56and 1.5340×10[3]+/-206.52 for polyethylene with 5% by weight, polyethylene with 2% by weight boron nano-particles, and pure polyethylene, respectively. The neutron spectrum after each shield was also obtained by MCNP4C Monte Carlo simulations. On the other hand, borated polyethylene nano-composites showed higher tensile strength compared to that of pure polyethylene. Attenuation of neutrons measured in experiments and the result of MCNP simulation were in good agreement

Conclusion: a statistically significant difference was found between neutron attenuation by borated polyethylene nanocomposite made of 5% by weight boron and pure polyethylene. However, the difference between borated polyethylene nano-composite with 5% weight and 2% wt boron was not statistically significant

Future role of vitamin C in radiation mitigation and its possible applications in manned deep space missions: survival study and the measurement of cell viability

Astronauts will be exposed to both chronic space radiation and acute high doses of energetic radiation of solar particle events in long-term deep space missions. The application of radioprotectors in space missions has basic limitations such as their very short time window as well as their acute toxicity and considerable side effects. The aim of the present study was to investigate the potential radiation mitigation effect of vitamin C that is known as an effective antioxidant and free radical scavenger. One hundred twenty male Wistar albino rats weighing 250-300 g were randomized into the following study groups: I, control; II, Only exposure to gamma-radiation [LD50/30]; treated with a single dose of vitamin C, III, 1h before irradiation, IV, V and VI, 1h, 12h and 24 h after irradiation. Measurement of cell viability and proliferation was also performed by using MTT cell proliferation assay. The survival rate in animals received vitamin C 1h, 12h and 24h after irradiation were 55%, 60%, and 80%, respectively. The viability of cells in animals received vitamin C 1h, 12h and 24h after irradiation were 94.9%, 99.0%, and 100%, respectively. The viability of the cells in animals only exposed to gamma rays was 50.1%. These findings reveal that a single dose of vitamin C can potentially be used up to 24 hours after exposure to reduce the detrimental effects of high levels of ionizing radiation in cases such as the occurrence of currently unpredictable solar particle events

Natural ventilation considerations for radon prone areas of Ramsar

In Iran, architectures are often unaware of the risk of radon inhalation and how to reduce radon levels. Furthermore, radon considerations are not implemented in construction methods, construction materials and building utilization by regulatory authorities. In this study after reviewing the meteorological changes of Ramsar over the past 50 years [1955-2005], a novel design for constructing dwellings in radon prone areas is introduced. Out of building interventions such as planting wind-tunnel-making trees will be discussed in another paper. Ramsar soil samples with 4 levels of specific activities [extremely hot, severely hot, very hot, and hot] were placed in a model house. Radon level monitoring was performed by using a PRASSI portable radon gas survey meter. For extremely hot soil samples, the radon levels inside the model house when windows were closed for 24 hours were 1615 +/- 516 Bq/m3. When windows which were in the wind direction or opposite the wind direction were opened for 24 h, the radon level decreased to 89 +/- 286 and 139 +/- 314 Bq/m3, respectively. Interestingly, when crossed windows were opened for the same duration, Radon level was 144 +/- 92 Bq/m3. In cold seasons, when windows are usually closed, Chimney effect reduced the radon level to 323 +/- 641. For severely hot, very hot and hot soil samples, natural ventilation-based interventions effectively reduced the radon level. Results obtained in this study clearly show that natural ventilation-based simple cost-effective interventions can significantly reduce the radon concentration in radon prone areas of Ramsar

Alterations of PSA, CA15.3, CA125, Cyfra21-1, CEA, CA19.9, AFP and Tag72 tumor markers in human blood serum due to long term exposure to high levels of natural background radiation in Ramsar, Iran

Ramsar [Mazandran province] is known for its extremely high levels of natural background radiation. Although no excess cancer rate is reported in these areas by epidemiological studies, the study of tumor markers in the inhabitants of these areas may shed some light on the impact of high levels of background radiation on cancer induction. The level of background gamma radiation as well as indoor radon was determined using RDS-110 and CR-39 dosimeters. Thirty five individuals from a high background radiation area [HBRA] and 53 individuals from a normal background radiation area [NBRA] were randomly selected to participate in the study. Commercial ELISA kits [sandwich type ELISA tests] were used to measure the serum levels of PSA, CA15.3, CA125, Cyfra21-1, CEA, CA19.9, AFP and Tag72 tumor markers. Among the eight biomarkers investigated, the means of PSA, CA15.3, CA125, CA19.9 and AFP concentrations between the HBRAs and NBRAs were not significantly different. However, Cyfra21, CEA and Tag72 in HBRA group revealed statistically significant increases compared to those of NBRA group [P<0.05]. Furthermore, a statistically significant correlation between the external gamma dose as well as indoor radon level and the concentration of CEA [P<0.001], Cyfra-21[P<0.001] and TAG 72 [P<0.001 and 0.01 respectively] biomarkers were observed. Chronic exposure to high background radiation induces significant alterations in Cyfra21, CEA and Tag72 levels. We believe that studies with other relevant tumor markers might overcome the limitations of epidemiological studies on cancer incidence in high background radiation areas

Production of a novel high strength heavy concrete using tourmaline and galena for neutron and photon radiation shielding

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 [60]Co buildup cap on a Theratron[60] Co 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/cm[3]. 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

Rectal wall dose estimation in intracavitary brachytherapy: a preliminary comparison of an in-house rectal wire versus ICRU 38 recommendations

In intracavitary brachytherapy for gynecological cancers, various techniques are used to locate the anterior rectal wall nearest to the sources but there is no consensus on the best method to do so. This study aimed to compare a technique used routinely in some centers that employs a wire marker to locate the position of the maximum rectal dose point, versus the method recommended by the ICRU Report 38. In a preliminary prospective study on 34 intracavitary insertions for patients with cervical or endometrial cancer, treated at our center based on the Manchester system, the dose distributions were obtained from a treatment planning system following the input of scanned orthogonal anteroposterior and lateral radiographs. For each case, an in-house marked wire was inserted in the rectal lumen and the doses were calculated on several points along the wire seen on the radiographs, to obtain the maximum dose. For the same insertions, the ICRU method was also applied by considering the rectal wall hot spot as a point 0.5 cm posterior to the posterior vaginal wall [visualized on the radiographs by vaginal packing material containing contrast medium]. Averaged over all insertions, mean rectal wall hot spot dose calculated using the positional information obtained by the wire technique was lower by 28.6% than that given by the ICRU method [P < 0.001]. Our initial results add evidence to the suggestion that the wire technique underestimates the rectal wall hot spot dose significantly compared to the ICRU method

Is it time to shed some light on the black box of health policies regarding the inhabitants of the high background radiation areas of Ramsar?

Although there are substantial experimental, epidemiological and clinical evidences that high doses of ionizing radiation cause cancer and other detrimental biological effects, the health effects of human exposure to chronic low dose radiation exposures are still poorly known. People in some areas around the world live in dwellings with radiation and radon levels as much as more than 200 times the global average. Inhabited areas with high levels of natural radiation are found in different areas around the world including Yangjiang, China; Kerala, India; Guarapari, Brazil and Ramsar, Iran. Ramsar in northern Iran is among the world's well-known areas with highest levels of natural radiation. Annual exposure levels in areas with elevated levels of natural radiation in Ramsar are up to 260 mGy y[-1] and average exposure rates are about 10 mGy y[-1] for a population of about 2000 residents. Due to the local geology, which includes high levels of radium in rocks, soils, and groundwater, Ramsar residents are also exposed to high levels of alpha activity in the form of ingested radium and radium decay progeny as well as very high radon levels in their dwellings. Based on the findings obtained by studies on the health effect of high levels of natural radiation in Ramsar, as well as other high background radiation areas, no consistent detrimental effect has been detected so far. Further research is needed to clarify if the regulatory authorities should set limiting regulations to protect the inhabitants against such extraordinary elevated levels of natural radiation

Short-term exposure to high levels of natural external gamma radiation does not induce survival adaptive response

In some areas of Ramsar, a city in northern Iran, residents receive a much higher annual radiation exposure than is permitted for radiation workers. Induction of adaptive response in residents of Ramsar has been reported previously. In this study induction of such a response in short term exposure to high background levels of gamma radiation is investigated. Fifty male NMRI mice were randomly divided into four groups of 10-17 animals and 53 Wistar rats were randomly divided into five groups of 10-12 animals were studied. Animals in the 1[st] group were kept for 7 days in an outdoor area with normal background radiation while the 2[nd], 3[rd], 4[th] and 5[th] [in case of rats] groups were kept in 3 different outdoor areas with naturally elevated levels of gamma radiation. Animals were then exposed to a lethal dose of 8 Gy gamma radiation. For mice, 30 days after exposure to lethal dose, the survival fraction for the control group was 40% while the 2[nd], 3[rd], and 4[th] groups had survival rates of 20%, 33.30%, and 35.20%, respectively. For rats, 30 days after exposure to the lethal dose, the survival fraction for the control group was 40% while the 2[nd], 3[rd], 4[th] and 5[th] groups had survival rates of 20%, 41.6%, 60.0% and 35.7%, respectively. Results indicate that short term exposure to extremely high levels of natural gamma radiation [up to 196 times higher than the normal background] do not lead to induction of survival adaptive response

comparative study on the increased radioresistance to lethal doses of gamma rays after exposure to microwave radiation and oral intake of flaxseed oil

Mobile phones, use electromagnetic radiation in the microwave range. On the other hand, there is only one report on radioprotective effects of flaxseed oil. The aim of this study was to investigate the effect of irradiation of rats with microwaves and/or treatment with flaxseed oil on the induction of adaptive response to a subsequent lethal dose [LD] of gamma rays. Eighty male rats were randomly divided into 6 groups of 13-15 animals. The animals in the 1[st] to 5[th] groups received microwave exposure, microwave+flaxseed oil [dissolved in olive oil], flaxseed [continued after LD], flaxseed, and olive oil. At day 5, all animals were whole-body irradiated with a previously reported LD 50/30 of 8 Gy gamma radiation. The 6th group [controls] received the same LD 50/30, but there was not any other treatment before or after the LD. No death event was observed during days 1-9 after LD irradiation in either group. At day 10, death events started in the 4[th] group. Thirty days after irradiation of the animals, the survival fractions for the control group, as expected, was 53.3% while there was no death event in the 1[st] group [survival rate of 100% in microwave-pretreated animals]. The survival fractions for the 2[nd] to 5[th] groups were 69.2%, 92.3%, 46.1%, and 61.5%, respectively. While these findings open new horizons in radiation protection, the radioresistance induced by microwave radiations emitted by a mobile phone may interfere with the outcome of any subsequent therapeutic application of photons or radioisotopes

Production of a datolite-based heavy concrete for shielding nuclear reactors and megavoltage radiotherapy rooms

Biological shielding of nuclear reactors has always been a great concern and decreasing the complexity and expense of these installations is of great interest. In this study, we used datolite and galena [DaGa] minerals for production of a high performance heavy concrete. Datolite and galena minerals which can be found in many parts of Iran were used in the concrete mix design. To measure the gamma radiation attenuation of the DaGa concrete samples, they were exposed to both narrow and wide beams of gamma rays emitted from a cobalt-60 radiotherapy unit. An Am-Be neutron source was used for assessing the shielding properties of the samples against neutrons. To test the compression strengths, both types of concrete mixes [DaGa and ordinary concrete] were investigated. The concrete samples had a density of 4420-4650 kg/m[3] compared to that of ordinary concrete [2300-2500 kg/m[3]] or barite high density concrete [up to 3500 kg/m[3]]. The measured half value layer thickness of the DaGa concrete samples for cobalt-60 gamma rays was much less than that of ordinary concrete [2.56 cm compared to 6.0 cm]. Furthermore, the galena concrete samples had a significantly higher compressive strength as well as 20% more neutron absorption. The DaGa concrete samples showed good shielding/ engineering properties in comparison with other reported samples made, using high-density materials other than depleted uranium. It is also more economic than the high-density concretes. DaGa concrete may be a suitable option for shielding nuclear reactors and megavoltage radiotherapy rooms

[ effect of radioactive lantern mantle powder and bentonite-zeoloite minerals on the volume of blood loss, bleeding and clotting time]

Over the past decade the US army has widely studied new technologies for stopping sever hemorrhages and has introduced an effective Zeolite based hemostatic agent. On the other hand, Mortazavi and his colleagues previously reported the bio-stimulatory effects of the topical application of radioactive lantern mantle powder on wound healing. Their subsequent studies showed significant changes in some histological parameters concerning healing. In this light, here the bio-stimulatory effect of burned radioactive lantern mantles powder as well as two minerals; bentonite and zeolite arepresented. This experimental study was conducted in the center for radiological studies, Shiraz university of Medical Sciences in 2008. Fifty male Wistar rats were divided randomly into 5 groups of 10 animals each. Following anesthesia, animals' tails were cut at a thickness of 5 mm by using a surgical scissor. No intervention was made on the animals of the 1[st] group. The 2[nd] group to 4[th] group received topical non-radioactive lantern mantle powder, radioactive lantern mantle powder, Bentonite mineral or a mixture of Bentonite-Zeoliteat minerals respectively. After treatment with above mentioned agents, the volume of blood loss was measured using a scaled test-tube. The bleeding time and clotting time were also measured using a chronometer. SPSS software was used for statistical analysis. ANOVA was used for comparing the means of each parameter in the 5 groups. The volume of blood loss, bleeding and clotting times in control animals were 4.39 +/- 1.92 cc, 112.10 +/- 39.60 sec and 94.9 +/- 54.26 sec, respectively. In the 5[th] group in which the animals were treated with a mixture of Bentonite-Zeoliteat minerals, the volume of blood loss, bleeding and clotting times were 1.31 +/- 0.60 cc, 34.50 +/- 4.65 sec and 24.2 +/- 4.61 sec, respectively. This is the 1[st] investigation that studied the alterations of bleeding and clotting times following the use of lantern mantle powder as well as bentonite or the mixture of bentonite-zeolite minerals. The results obtained in this study clearly show the significant effect of the volume of blood loss as well as the bleeding time following the topical use of the mixture of bentonite-zeolite minerals. The radioactive and non-radioactive lantern mantle and the bentonite mineral alone had considerable effects but overally the magnitude of the effect was less than that of the mixture of bentonite-zeolite minerals

[The effect of microwave radiation emitted by mobile phones on human short term memory]

The widespread use of cell phones has made the researchers focus on its health effects. However, the biological effects of electromagnetic fields have not been clearly known. This study was performed to determine the effect of microwave radiation emitted by mobile phones on the human short term memory. This interventional study has been performed on 70 male sets who were studying at Rafsanjani University of Medical sciences [RUMS] in 2006. Participants were divided into two groups. The First group which included 25 students whose short term memory was tested by using Wechsler test. Ten minute real/sham exposure intervals to microwave radiations emitted from a mobile phone were performed at 0 h [sham], 24 h [real] and 48 h [sham] and the participants were tested using 5 Wechsler subsets immediately after each real/sham exposure. The second group included 45 males were exposed/ sham exposed to microwave radiation at 0 h [real], 24 h [sham]. Data were statistically analyzed using student's t test. The means of memory scores in both groups were increased in the next day. This clearly shows the role of learning in these tests. No statistical relationship was found between exposure to the microwave radiation and memory scores. Overall the data could not show a significant effect of the mobile phone on short term memory. Repeating the memory tests after 24, 48 h clearly increased the scores in both groups. These findings confirm the role of learning in memory tests and lack of any link to cell phone use

survey on stimulatory effects of topical application of radioactive lantern mantle powder on wound healing

Poorly educated people in some parts of Iran use burned mantles as a wound healing medicine. To perform surface area measurement, twenty rats were divided randomly into two groups of 10 animals each. The first group received topical burned radioactive lantern mantle powder on the first to third days after making excision wounds. The second group received non-radioactive lantern mantle powder. For histological study, 36 male rats were randomly divided into two groups of 18 animals each. Full thickness excision wound [314 +/- 31.4 mm[2]] was made on the dorsal neck in all animals after inducing general anesthesia. For the first three days, cases had received topical application of the radioactive lantern mantle powder. Finally, to measure the tensile strength, an incision was made on the dorsal neck of the rats. Surface area measurement of the wounds showed a progressive surface reduction in both groups. Histological study showed a significant statistically difference between cases and controls with respect to fibrinoid necrosis and neutrophilic exudate on days 3 and 14. Considering the existence of granulated tissue, a significant difference was observed between case and control groups on days 3 and 7. Tensile strength study showed no significant difference between the cases and controls. Topical use of radioactive mantle powder can accelerate the healing process of the wound in rats

[Increased mercury release from dental amalgam restorations after brain magnetic resonance imaging]

The introduction of magnetic resonance [MR] technology as a clinical imaging method has substantially increased the patient exposure to static, gradient and radio frequency of electromagnetic fields. The aim of this study was to assess the release of mercury from human dental amalgam restorations after exposure to electromagnetic fields produced by conventional MR imaging. The pre- and post-interventional study design was used for this investigation. The study participants were composed of individuals who were scheduled for brain MRI and those who had at least 4 teeth with amalgam restorations. These restorations had to be at least one week or older. Thirty individuals, who met the inclusion criteria, were referred to magnetic resonance imaging [MRI] department. A questionnaire was used for each patient to collect basic information on past exposures to electromagnetic fields, occupation and life style. Biological specimens [5cc stimulated saliva] were collected just before and after MRI procedures. The magnetic flux density was 0.23 T, and the patient's duration of exposure to magnetic field was 30 minutes. The collected saliva samples were analyzed by laboratory for mercury level by using cold-vapor atomic absorption technique. The SPSS software and paired t-test were used for statistical analysis of mercury levels. The mean concentrations of mercury in saliva before and after MRI were 0.86 +/- 0.3 mg /dl and 1.13 +/- 0.5 mg /dl respectively. Data analysis using paired t-test showed a statistically significant difference between the mean concentrations of saliva mercury before and after MRI procedures. This study showed significant relationship between increased mercury levels in saliva of patients exposed to magnetic resonance imaging

[Effect of gamma irradiation sterilization on the osteoinductive capacity of demineralized bone matrix]

Gamma irradiation has been widely used for secondary sterilization of bone allograft before clinical use to reduce the risk of infection and associated complications. The current study evaluated the effect of gamma irradiation sterilization on the osteoinductive capability of human demineralized bone matrix using a rat model. Eighteen euthymic rats received two separate implants consisting of 30 mg sterile-harvest demineralized bone matrix and 30 mg gamma irradiation-sterilized demineralized bone matrix. The demineralized bone matrix from each group was placed into two separate muscle pouches created in the paravertebral muscles of each rat. All 18 rats were euthanized after 4 weeks and each implantation site was removed with 0, 5 cm normal tissue around the implant. Histological examination was performed to determine the presence or absence of new bone, cartilage and bone marrow elements, All except one of 18 [94.4%] sterile-harvest demineralized bone matrix sites histologically contained new bone elements and five of 18 [27.7%] ethylene oxide sterilized demineralized bone matrix sites showed evidence of new bone elements, which was statistically significant [p<0.05]. The results of this study indicate that demineralized bone matrix sterilized with gamma irradiation loses its osteoinductive capacity in a manner similar to that of steamsterilized demineralized bone matrix, making it unsuitable as a method of secondary sterilization of demineralized bone matrix

Production of an economic high-density concrete for shielding megavoltage radiotherapy rooms and muclear reactors

In megavoltage radiotherapy rooms, ordinary concrete is usually used due to its low construction costs, although higher density concrete are sometimes used, as well. The use of high-density concrete decreases the required thickness of the concrete barrier; hence, its disadvantage is its high cost. In a nuclear reactor, neutron radiation is the most difficult to shield. A method for production of economic high-density concrete with appropriate engineering properties would be very useful. Galena [PbS] mineral was used to produce of a high-density concrete. Galena can be found in many parts of Iran. Two types of concrete mixes were produced. The water-to-concrete [w/c] ratios of the reference and galena concrete mixes were 0.53 and 0.25, respectively. To measure the gamma radiation attenuation of Galena concrete samples, they were exposed to a narrow beam of gamma rays emitted from a cobalt-60 therapy unit. The Galena mineral used in this study had a density of 7400 kg/m[3]. The concrete samples had a density of 4800 kg/m[3]. The measured half value layer thickness of the Galena concrete samples for cobalt- 60 gamma rays was much less than that of ordinary concrete [2.6 cm compared to 6.0 cm]. Furthermore, the galena concrete samples had significantly higher compressive strength [500 kg/cm[2] compared to 300 kg/cm[2]]. The Galena concrete samples made in our laboratories had showed good shielding/engineering properties in comparison with all samples made by using high-density materials other than depleted uranium. Based on the preliminary results, Galena concrete is maybe a suitable option where high-density concrete is required in megavoltage radiotherapy rooms as well as nuclear reactors