Background: Exposure to ionizing RADIATION has harmful health effects. Research shows that people spend more their time indoors than outdoors. Therefore, the indoor background ionizing RADIATION can pose a noticeable health risk. Objectives: Since it is well established that ionizing RADIATION can lead to serious health problems, the present study aimed to evaluate the level of ionizing RADIATION in the background environment in radiological centers in Ahvaz, Iran. Methods: The evaluation of indoor and outdoor background ionizing RADIATION levels was carried out by using the calibrated digital Geiger-Muller counter (S. E. International Inc., USA) in five radiography centers. The background RADIATION was measured both indoor and outdoor of the selected radiology centers in four locations. The measured locations included behind the door of the X-ray room, outdoor, waiting room for the people, and the reception section in each center. The measurements were done with a device held one meter above the floor. Results: The indoor RADIATION levels were 0. 13 ± 0. 004, 0. 11 ± 0. 004, 0. 13 ± 0. 004, 0. 16 ± 0. 007, and 0. 16 ± 0. 006 µ Sv/h for centers a, b, c, d, and e, respectively, and the outdoor RADIATION levels were 0. 12 ± 0. 02, 0. 11 ± 0. 01, 0. 10 ± 0. 00, 0. 12 ± 0. 01, and 0. 13 ± 0. 00 µ Sv/h, respectively. Conclusions: The mean equivalent dose in this study was lower than the standard level (1 mSv/y); therefore, the radiology centers were safe.

According to International Atomic Energy Agency (IAEA) recommendations, the calibration of IONIZATION chambers used for radiotherapy dosimetry follows the substitution method which demands the use of a reference IONIZATION chamber. This work introduces the Design and fabrication of cylindrical IONIZATION chamber for dosimetry to be used by standard dosimetry laboratories. The result of the quality control tests in Secondary Standard Dosimetry Laboratory (SSDL) of the Atomic Energy Organization Which was carried out in accordance with the standards and limits set by the International Atomic Energy Agency, are evidence of the accuracy of the claim that this chamber can be used as a reference dosimeter in standard dosimetric laboratories. The low polarity effect and leakage current, high ion collection efficiency and stability, linear response of the detector to the dose and the rate of dosing are some of this instrument characteristic through optimum design of guard ring and collecting electrode and also the proper choice of materials in fabrication.

Background: Absolute dosimetry of external beam radiotherapy is carried out by the use of IONIZATION chambers. These chambers must be calibrated at a standard dosimetry laboratory before any use in clinical dosimetry. The secondary standard dosimetry laboratory of Iran (SSDL) has the duty of calibrating the IONIZATION chambers used in radiotherapy centers in Iran.Materials and Methods: The present work has described traceability of SSDL RADIATION measurement standards to relevant international standards, and calibration of therapy level IONIZATION chambers in terms of air kerma and absorbed dose to water against 60Co gamma RADIATION, as well as uncertainty evaluation of calibration coefficients.Results: The expanded uncertainties in the determination of air kerma and absorbed dose to water are estimated to be 2% and 2.3% at approximately 95% confidence level, respectively.Conclusion: In order to maintain the requirement of ±5% accuracy in the dose delivery, the combined standard uncertainty of the other factors in the dose delivery; i.e., dose measurement set-up, dose calculations, treatment planning, patient set-up, etc, should be less than 2.3%.

Background: The Cell phones are a major part of people's lives in contemporary societies. Might their RADIATION be able to affect some cognitive functions while people drive? This study aims to investigate the effect of cell phone RADIATION on the brain’s cognitive functions. Materials and Method: Forty female students without depression or anxiety volunteered in the cross-sectional study. During one session, the volunteers were randomly exposed to cell phone RADIATION (20 participants in the first and 20 participants in the second). Participants performed four cognitive tests in each session. A p-value of less than 0.05 was taken as the cut-off point to consider a statistically significant result. Results: In the congruent part of the Stroop test, the reaction time (RT) was reduced in both groups during the time volunteers were exposed to RADIATION and there were significant differences between sessions in both groups (P=0.005 and P<0.001). These differences were significant between the two groups in different sessions. However, the number of errors decreased during exposure to RADIATION and this difference was significant in the first group (P=0.015). In the incongruent part of the Stroop test, the treatment showed that the RADIATION of mobile phones had a significant effect on the reduction of RT (P<0.001). Conclusion: Based on this study, it seems that cell phone RADIATION waves have a limited effect on RT, cognitive and executive function. Therefore, traffic accidents that occur during a mobile phone conversation might be solely due to the division of attention rather than a direct effect of cell phone waves.

Introduction & Objective: The use of computers and monitors (displays) has been developed due to their increasing capabilities. The presence of electromagnetic fields, infrared and ultraviolet RADIATIONs has been proven around the display, which all of them have adverse effects on human health. Therefore, this study was conducted to survey and compare the mentioned variables around the displays.Material & Methods: The present descriptive–analytical study was accomplished in Hamadan university of medical sciences in 2011. The statistical sample included 46 LCD and 50 CRT devices selected by simple random sampling. In order to assay the electric and magnetic fields, the HI-3604 device and for measuring the IR and UV rays, Hanger device was used.Results: The magnetic field in the CRT display was higher than the LCD display. Also the magnetic field of the front of the display was more than back position in the both displays (P=0.000). The electric field in the nearest distance of the display was higher in CRT than LCD (P=0.000). In 30 cm distances of CRT and LCD displays, 96% and 8.3% of the samples had magnetic field more than TCO standard, respectively.Conclusions: The current finding demonstrated that LCD displays radiate much lower amount of magnetic field, IR and UV rays than CRT displays. Life extension of the system has a great influence on the production of electromagnetic fields.

The buildup factor is becoming a required parameter for exposure and energy absorption in the area of RADIATION physics for shielding, dosimetry, health physics and medical physics. In this research, photon buildup for dysprosium doped lithium magnesium borate glasses system has been investigated. Photon energy absorption buildup factors and photon exposure buildup factors were computed for the chosen glasses using the fi ve-parameter geometric progression fi tting method in energy range of 0. 015 MeV to 15 MeV. Also, eff ective and equivalent atomic numbers were calculated for these compositions and discussed for possible implementation in RADIATION dosimetry.

Background: Application of ionizing RADIATION in many fields especially in medicine is growing, and can cause adverse health effects.Objectives: The current study aimed to evaluate the RADIATION protection principles in radiology departments, based on national standards.Materials and Methods: The current study was conducted in all radiology departments of the teaching hospitals in Ahvaz, Iran, and their RADIATION protection status was investigated using Audit technique. For this purpose Audit checklist was prepared and essential information gathered by observation, interview with radiology department managers, and documentary surveying. At the end, standard situations were classified in three levels: poor (˂ 50%), medium (50 - 75%), and good (75 - 100%).Results: The mean of RADIATION protection in the studied radiology departments was 70.53%. The highest and lowest levels of RADIATION protection were in quality control and suitable ventilation, respectively. RADIATION protection was evaluated as medium in 71.4% and good in 28.6% of the studied radiology departments.Conclusions: The state of observed RADIATION protection principles was relatively in the weak level in the studied radiology departments especially in facilities such as ventilation system, radiography entrance, and darkroom situation. More important reason was usage changing of sections as radiology billet from related organizations.

Background: Protection of hematopoietic system has become a primary goal in the development of novel medical countermeasures against IONIZATION RADIATION and radiotherapy. This study was to explore the role of rapamycin in normal tissues against RADIATION. Materials and Methods: Mice were pretreated with rapamycin by i. p. every other day for five times before 5 Gy or 8. 5 Gy γ-ray whole body irRADIATION. Blood cell counts, HE staining of bone marrow and liver, bone marrow transplantation, CFU of spleen were used to measure the damage of hematopoiesis and extramedullary hemopoietic organs. Regular karyotype analysis and expression of γ-H2AX (by flow cytometry and western blot) were used to measure DNA damage. Rad 50 and DNA Lig 4 expression by western blot were to see the DNA repair ability. Results: The decrease of red blood cells and platelet induced by RADIATION were alleviated by pretreatment with rapamycin (d 7, 15, p<0. 01), and the long-term restoration of white blood cells, lymphocytes and bone marrow were enhanced in rapamycin pretreatment group (d 30, 40, 70, p<0. 05). The transplantation experiment also indicates that the long-term reconstitution in lethally irradiated recipient mice was improved in rapamycin group (p<0. 05). The hepatocellular injury by RADIATION was also reduced and the colony formation numbers of spleen after irRADIATION was improved in rapamycin group (p<0. 05). Karyotype analysis indicates that rapamycin protected bone marrow cells from chromosome mutation. Furthermore, expression of DNA repair proteins Rad 50 and DNA Lig 4 was enhanced and DNA damage marker γ-H2AX was reduced in mice exposed to RADIATION by rapamycin pretreatment. Conclusion: Rapamycin pretreatment mitigates hematopoietic system from RADIATION injury in both bone marrow and extramedullary hematopoietic organs by improving genomic stability and increasing survival of hematopoietic stem and progenitor cells (HSPCs).

Background: In order to deliver the precise dose to the target in radiotherapy, absorbed dose to water at the reference point should be assessed. When the calibration procedure is performed for a reference dosimeter in the 60Co beam of a Secondary Standard Dosimetry Laboratory (SSDL), the total uncertainty in absorbed dose to water (Dw) is estimated to be approximately 1.5%. This study a) empts to re-measure the ND, W factors for all available field chambers at Reza Radiotherapy & Oncology Centre (RROC).Materials and Methods: Consistency and linearity checks were performed for a range of available chambers using a check source. The ND, W factors were also measured for the IONIZATION chambers. All cylindrical chambers have been cross calibrated at 6 MV photon beam using a Siemens Primus Plus Linac. The Plane Parallel Chamber has been cross calibrated at the highest available electron beam and the ND, W factor has been measured.Results: The tolerance of consistency and linearity checks has been reported to be within 0.3%. The ND, W value for field Farmer chamber was found in agreement with certificate within 1%. In contrast for small active volume chambers, the deviation from the SSDL reports was 2.3%. For the plane parallel chamber, the difference between SSDL and Home measurements are found to be 12%.Conclusion: Although the calibration of reference chambers used for absolute dosimetry through a Primary Standard Dosimetry Laboratory (PSDL) or SSDL is recommended, for field chambers this can be done at home department as a Tertiary Standard Dosimetry Laboratory (TSDL).

Background: Using ionizing RADIATION in diagnosis and treatment is of great importance. As early diagnosis in some diseases only can be done by using RADIATION, in treatment phase, radiotherapy is also the main center for healing patients with cancer. Today, one of occupational hazards is ionizing RADIATION which can cause serious and irreparable damages in RADIATION workers. This study aimed to count blood cells and evaluate liver enzymes and thyroid-stimulating hormone (TSH) in RADIATION workers in hospitals in Kurdistan Province, Iran.Methods: In this case-control study, blood cells, liver enzymes, and TSH levels were compared in 142 RADIATION staff (cases) and also 142 workers in other sections of hospitals. Matching was done for confounding factors. The statistical analysis was performed using SPSS software at the significance level of P<0.05.Findings: Mean number of white blood cells and the level of serum alanine aminotransferase (ALT) enzyme in RADIATION staff were significantly different from that of the control group. But no significant difference was observed between other parameters.Conclusion: It seems that working in RADIATION wards can change some blood factors but cannot predict the recieved dose. In order to increase the safety of RADIATION workers in RADIATION wards, monitoring of these individuals should be done annually using cytogenetic methods.