Background: Radiation dose in C-arm procedure and radiography may lead to late complications such as cancer. Entrance surface dose (ESD) and dose area product (DAP) are two practical indicators for patient dose estimation. This study aimed to calculate ESD and DAP based on exposure parameters for the most common radiographic examinations in educational hospitals of Hamadan. Methods: This work was conducted in three radiography centers in Hamadan in 2020. ESD was determined using a standard equation. Radiation parameters, including maximum kilovolt and milliampere-seconds (mAs), were obtained from the device console, and the output factor was obtained from the calibration certificate. Eventually, ESD and DAP were computed for the head, chest, abdomen, and pelvic radiography examinations. Results: Means of ESD and DAP were 0. 68±0. 44 mGy and 274. 03±179. 84 mGy. cm2 for head, as well as 0. 13±0. 07 mGy and 117. 64±70. 07 mGy. cm2 for chest. In addition, the corresponding valures were 1. 31±0. 82 mGy and 1187. 17±738. 3 mGy. cm2 for the abdomen, as well as 0. 84±0. 83 mGy and 764. 84±753. 59 mGy. cm2 for the pelvic. The difference in ESD and DAP for all examinations between centers was significant (P<0. 05). Conclusion: Several factors affect radiation exposure and patient dose in radiography. Some of these factors are subjective and depend on technician knowledge. It is possible to reduce the patients’ dose while maintaining image quality by regular training of technicians.

Background Patients' dosimetry is crucial in order to enhance radiation protection optimization and to deliver low radiation dose to the patients in a radiological procedure. The aim of this study was to assess the entrance surface dose (ESD) and radiation dose to the radiosensitive organs in pediatric pelvic radiography. Materials and Methods: The studied population included 98 pediatric patients of both genders referred to anteroposterior (AP) projection of pelvic radiography. The radiation dose was directly measured using high radiosensitive cylindrical lithium fluoride thermo-luminescent dosimeters (TLD-GR200). Two TLDs were placed at the center point of the radiation field to measure the ESD of pelvis. Moreover for each patient, 2 TLDs were placed upon each eyelid, 2 TLDs upon each breast, 2 TLDs upon the surface anatomical position of the thyroid gland and finally 2 TLDs at the surface anatomical position of the gonads to measure the received dose. Results The ESD ± standard deviation for AP pelvic radiography was obtained 591. 7± 76 μ Gy. Statistically significant difference was obtained between organs located outside and inside of the radiation field with respect to dose received (P<0. 001), as well as between the average dose received by the breast and lens of the eyes (P<0. 05). There was no difference between boys and girls with respect to average ESD, while the testes dose was statistically non-significantly lower than ovaries dose. Conclusion The ESD received by patients are relatively accordance to the international recommendations. However further reduction in patients' dose in achievable by adherence to the radiation protection optimization guidelines. The data presented in our study will serve as a baseline needed for deriving local reference doses for pediatric pelvic radiography in our hospital. The study is expected to increase the awareness of medical professionals about the radiation doses in pediatric pelvic radiography.

Background: The activity concentration (AC) of cesium-137 (137Cs) in the agricultural soil was measured in this study to set reference data and an indicator of the radionuclide fallout especially in Malaysia. Materials and Method: Using the High Purity Germanium (HPGe) gamma-ray spectrometer, the AC of 137Cs was employed to determine the radiological hazards to the public. Results: Results revealed that the AC of 137Cs in the soil samples ranged between 0. 34 ±,0. 09 to 3. 21 ±,0. 17 Bqkg-1. Dose rate computed from the corresponding value of AC ranged from 0. 01 to 0. 10 nGyh-1. The annual effective dose rate ranged between 1. 25 to 11. 8 μ, Sv y-1. The values of Excessive lifetime cancer risk, ELCR ranged between 0. 47 × 10-5 to 4. 45 × 10-5 is lesser than the safety threshold of 0. 29 × 10−, 3. The analysis of variance of this parameter is found to be at p<0. 05 which is statistically significant in this study. Conclusion: The outcomes from this study show that the analysed values are below than the recommended values by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNCSEAR) and The International Commission on Radiological Protection (ICRP) and do not cause any radiological hazards to the general population.

Background: Panoramic radiography is one of the common dental imaging procedures using ionizing radiation. It is necessary to control the level of exposure and use the optimized levels. So, the current work aimed to estimate the surface absorbed doses of critical organ regions, namely thyroid and parotid glands. Moreover, dose area product (DAP) values were measured and a local DRL was then established for panoramic radiography. Materials and Methods: The data from 201 patients including 141 adults and 60 children (5-10 years) were used for this cross-sectional study. Seven panoramic radiography systems were selected from 6 radiology clinics in Yazd province. For each patient, 12 thermoluminescence dosimeters (TLD GR-200) were used to obtain the surface absorbed dose in both the thyroid and parotid gland regions. The DRL values were calculated using DAP values in terms of the ICRP recommendation. Results: The mean and standard deviation (SD) of thyroid and parotid glands’,surface absorbed doses were equal to 60. 6±, 3. 7 and 290±, 12. 4 μ, Gy in the adult group, respectively. In the children group, these values were 40. 7±, 2 and 189. 3±, 11. 5 μ, Gy, respectively. Moreover, the local DRL values were obtained as 99. 7 and 73. 4 mGy. cm2 for the adults and children groups, respectively. Conclusion: The higher surface absorbed dose values in the adult group can be related to the use of higher radiation parameters. The local DRL proposed for the adult and pediatric groups in the current study was relatively lower than those established by other reports, which seemed acceptable for panoramic radiography in Yazd, Iran.

Background: Mul ple beams are generally used with an increased possibility that the beam axis intersects the treatment table. Treatment tabletops are commonly made of carbon fiber due to its high mechanical strength and rigidity, low specific density, extremely light and low radia on beam a enua on proper es. Purpose of this paper is inves gated the dose changes in the buildup region and beam a enua on by a carbon fiber tabletop for high energy 6-and 18-MV photon beams. Materials and Methods: Measurements were performed for 10 cm × 10 cm and 20 cm × 20 cm field sizes. The surface dose and percentage depth doses (%DD) were measured by a Markus parallel plate chamber at a source-surface distance (SSD) of 100 cm for 6 MV and 18 MV photon beams. A enua on measurements were made at the solid-water phantom for gantry angles of 0o and 180o rota on of the beam. Results: A carbon fiber tabletop increases the surface dose from 12. 87% to 86. 65% for 10 cm x 10 cm and from 8. 72% to 71. 16% for 20 cm × 20 cm field at 6 and 18 MV, respec vely. The surface dose with the carbon fiber tabletop in an open field (0o) increases with field size. Conclusion: The carbon fiber tabletop causes a substan ally increased surface dose, and also significantly decreases the skin-sparing effect, which is clinically important. The dosimetric effect of the tabletop may be higher, especially for the intensitymodulated radia on therapy depending on the beam orienta on.