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Aim: In this study, we aimed to determine possible mitigation of radiationinduced toxicities in the duodenum, jejunum and colon using post-exposure treatment with resveratrol and alpha-lipoic acid. Background: After the bone marrow, gastrointestinal system toxicity is the second critical cause of death following whole-body exposure to radiation. Its side effects reduce the quality of life of patients who have undergone radiotherapy. Resveratrol has an antioxidant effect and stimulates DNA damage responses (DDRs). Alpha-lipoic acid neutralizes free radicals via the recycling of ascorbic acid and alpha-tocopherol. Objective: This study is a pilot investigation of the mitigation of enteritis using resveratrol and alpha-lipoic acid following histopathological study. Methods: 60 male mice were randomly assigned to six groups; control, resveratrol treatment, alpha-lipoic acid treatment, whole-body irradiation, irradiation plus resveratrol, and irradiation plus alpha-lipoic acid. The mice were irradiated with a single dose of 7 Gy from a cobalt-60 gamma-ray source. Treatment with resveratrol or alpha-lipoic acid started 24 h after irradiation and continued for 4 weeks. All mice were sacrificed after 30 days for histopathological evaluation of radiation-induced toxicities in the duodenum, jejunum and colon. Results and Conclusion: Exposure to radiation caused mild to severe damages to vessels, goblet cells and villous. It also led to significant infiltration of macrophages and leukocytes, especially in the colon. Both resveratrol and alpha-lipoic acid were able to mitigate morphological changes. However, they could not mitigate vascular injury. Conclusion: Resveratrol and alpha-lipoic acid could mitigate radiation-induced injuries in the small and large intestine. A comparison between these agents showed that resveratrol may be a more effective mitigator compared to alpha-lipoic acid.

Although radiation exposure associated with dental radiography is relatively low, patient exposure must be kept practically low. Therefore, it is necessary for each country to establish its own diagnostic reference levels (DRLs) suitable for its equipment and practice. In the present study, dose-width product (DWP) values for panoramic dental radiography were measured and a local DRL was established. Five panoramic devices from five radiology clinics of Kashan, Iran were selected to measure the DWP values of panoramic dental radiography. To investigate the DWP values, the parameters of each patient’s exposure (e.g., tube voltage, tube current, and exposure time) at these five radiology clinics were extracted. Then, the dose value received by each patient was measured based on a CT pencil chamber. Finally, the overall median DWP values for the patients with small, medium, and large sizes were obtained, and these values were considered as the local DRLs for panoramic dental radiography. A total of 99 adult patients were included in the present study. The findings demonstrated that the median and third-quartile DWP values for these five radiology clinics ranged from 42.3 to 94.3 and 49.7 to 142.8 mGy mm, respectively. The local DRL values, which were established as the overall median DWP values, were 43.4, 52.0, and 80.3 mGy mm for the adults with small, medium, and large sizes, respectively. The local DRL proposed in this study for the adult with standard/medium size was lower than those proposed by other reports and seemed acceptable for panoramic radiography in Kashan, Iran.

The dose values obtained from procedures of diagnostic radiology are relatively low. To accurately and precisely measure the dose values in this dose range, it is necessary to know the characteristics of dosimeters.The aim of this study was to evaluate several thermoluminescent characteristics of GR-200, TLD-700H and TLD-100 for low dose measurement.In this experimental study, linearity, repeatability, dose rate and photon energy dependence of different TLD materials were investigated in a 0.05-10 mGy range dose. It is noteworthy that the data obtained from TLD-100 were considered as reference and the data obtained from two other types of TLDs were compared with them.For all three types of TLD materials, there are linear relations between absorbed dose values to TLDs and their responses. TLD-100 and TLD-700H have very low sensitivity than GR-200. For GR-200 and TLD-100, the coefficients of variation values (%) are 3.00% and 2.01%, respectively, that these values are within the tolerance limit (7.5%). However, this value for TLD-700H is 10.85% which it is more than the reported tolerance limit. Furthermore, remarkable effects of dose rate and photon energy dependence on the responses of GR-200 are not observed in a 0.5-4 mGy dose range; nevertheless, remarkable effects of dose rate and photon energy dependence on the responses of TLD-100 and TLD-700H are found in this dose range.The evaluated thermoluminescent characteristics for GR-200 are better than two other types of TLDs (TLD-100 and TLD-700H) for low dose values.

Computed tomography (CT) is one of the most important diagnostic X-ray procedures which plays an important role in increasing the patient dose values. The purpose of this clinical study was to evaluate the efficacy of vitamins E and C in lowering down the level of DNA double strand break (DSB) caused by CT scan. Sixty patients for abdomen/pelvic enhanced CT scan were randomly assigned to placebo (control), vitamin C, and vitamin E groups. The patient blood samples were taken before and immediately after the CT scan. Counting the number of DSB was performed using γ-H2AX method as a sensitive biomarker. Immediately after the CT scan, the mean number of DSBs/cell increased in all three groups of control (131%, P

The severe toxicity in compound of polymer gel dosimeters has been reported as one of their major limitations for utilization in clinical applications. Recently, PASSAG polymer gel dosimeter has been introduced as a safe polymer gel dosimeter. Despite the excellent dosimetric results reported for this gel dosimeter, its R2-dose sensitivity is relatively low. Therefore, the present study is aimed to improve the sensitivity of PASSAG gel dosimeter by adding urea to its structure. Moreover, it was tried to obtain the optimal amount of urea for the new gel dosimeter. After preparation of the PASSAG-U (PASSAG and Urea) gel dosimeters, they were irradiated using 6 MV photon energy and their responses were read by a 1.5 T MRI scanner. Then, the R2-dose response and the R2-dose sensitivity of the PASSAG-U gel dosimeters with various percentages of the urea were assessed at a 0–10 Gy dose range, various scanning temperatures (15–24 °C), and post irradiation times (1–30 days). The radiological properties of PASSAG-U gel dosimeters confirmed soft tissue and water equivalence of the new gel dosimeters. Compared to the PASSAG gel dosimeter, the R2-dose sensitivities of PASSAG-U gel dosimeters with 1%, 3%, and 5% urea were improved by 12.14%, 25.15%, and 27.90%, respectively. Although the addition of urea improves the R2-dose sensitivity of the gel dosimeter, it leads to the degradation of dose resolution (especially for 5% urea). Moreover, the dosimetric evaluation of characteristics related to the PASSAG-U gel dosimeters with various urea concentrations resulted to following conclusions: 1) the optimal amount of urea was determined 3%; 2) there was a stability in the R2 values for 18–22 °C scanning temperatures; 3) there was a temporal stability at the response of PASSAG-U gel dosimeters from 14 to 30 days after irradiation; 4) the R2-dose sensitivity of PASSAG-U gel dosimeters varied over post irradiation time.

Background: The current study aimed to determine the cumulative effective dose caused by diagnostic imaging and its associated risk for cancer development in trauma patients referred to an emergency department. Methods: This study was carried out retrospectively in an emergency department (Kashan, Iran) from April 2015 to October 2015. Then, the types of diagnostic radiologic studies performed on adult trauma patients in their first 24 h upon presentation were recorded. Finally, the cumulative effective dose of trauma patients and its associated risk for cancer development were obtained. Results: In total, the patients received 3323 radiologic examinations including 2169 radiographs and 1154 computed tomography (CT)-scans. The most common type of plain radiographic and CT-scan examinations included anterior posterior and posterior anterior chest as well as head, respectively. The mean cumulative effective dose received by trauma patients referred to the emergency department was 2.47 ± 4.29 mSv. Most of the effective dose was from CT-scan examinations (90.65% of total cumulative effective dose; 2181.91 mSv). The majority of patients (83.40%) received between 0.00 and 5.00 mSv cumulative effective dose. Moreover, the cancer risk per average cumulative effective dose received by trauma patients was 1.01 × 10−4. Conclusions: In current study, the mean cumulative effective dose per each trauma patient (2.47 mSv) was relatively less than that of the other evaluated studies. It was also found that although the number of CT-scans was relatively few compared to plain radiographs, most of the cumulative effective dose of patients resulted from CT-scans; hence, using unnecessary CT-scan examinations should be avoided.

Background : There is no geometrical nucleotide resolution model which can be used in numerical simulations of the interaction between radiation and supercoiled mt-DNA to perform realistic evaluations of DNA–free radical reactions. Objectives: A new geometrical model of mitochondrial DNA (mt-DNA) is developed in Geant 4-DNA to investigate the radiation-induced damage on mt-DNA. The presented application can be used to modify both geometrical parameters and structural elements, and to evaluate the damage induced on the mt-DNA molecule by ionizing particles. Methods : Our model covers the organisation of a supercoiled human mitochondrial genetic system. The current model includes all 16,659 base pairs of human mitochondrial DNA. This new mtDNA model has been preliminarily tested in this work by determining SSB and DSB DNA damage yields and site-hit probabilities due to the impact of proton particles. Results : Determination of single-strand (SSBs) and double-strand breaks (DSBs) is designed using the locations of all hit sites. Estimation of single-strand breaks and double strand breaks yielded similar results with the increment of incident particle LET. The output results contain the information about the energy transfers in the backbone region of DNA double helix. Conclusions : Considerations seem to be consistent with the corresponding experimental determinations. This application can be used for the investigation of radiation-induced damage to the mitochondrial genome and in any problems that require a supercoiled geometrical model. This work is going to be extended to circular conformation in a parallel project in the near future.

Objective: The Lung is one of the most radiosensitive organs of the body. The infiltration of macrophages and lymphocytes into the lung is mediated via the stimulation of T-helper 2 cytokines such as IL-4 and IL-13, which play a key role in the development of fibrosis. It is likely that these cytokines induce chronic oxidative damage and inflammation through the upregulation of Duox1 and Duox2, which can increase the risk of late effects of ionizing radiation (IR) such as fibrosis and carcinogenesis. In the present study, we aimed to evaluate the possible increase of IL-4 and IL-13 levels, as well as their downstream genes such as IL4ra1, IL13ra2, Duox1, and Duox2. Materials and Methods: In this experimental animal study, male rats were divided into 4 groups: i. Control, ii. Melatonintreated, iii. Radiation, and iv. Melatonin (100 mg/kg) plus radiation. Rats were irradiated with 15 Gy 60Co gamma rays and then sacrificed after 67 days. The expressions of IL4ra1, IL13ra2, Duox1, and Duox2, as well as the levels of IL-4 and IL-13, were evaluated. The histopathological changes such as the infiltration of inflammatory cells, edema, and fibrosis were also examined. Moreover, the protective effect of melatonin on these parameters was also determined. Results: Results showed a 1.5-fold increase in the level of IL-4, a 5-fold increase in the expression of IL4ra1, and a 3-fold increase in the expressions of Duox1 and Duox2. However, results showed no change for IL-13 and no detectable expression of IL13ra2. This was associated with increased infiltration of macrophages, lymphocytes, and mast cells. Melatonin treatment before irradiation completely reversed these changes. Conclusion: This study has shown the upregulation of IL-4-IL4ra1-Duox2 signaling pathway following lung irradiation. It is possible that melatonin protects against IR-induced lung injury via the downregulation of this pathway and attenuation of inflammatory cells infiltration.

Background The aim of this study was to develop a nucleotide geometrical model of the circular mitochondrial DNA (mt-DNA) structure using Geant4-DNA toolkit to predict the radiation-induced damages such as single-strand breaks (SSB), double-strand breaks (DSB), and some other physical parameters. Methods Our model covers the organization of a circular human mt genetic system. The current model includes all 16,659 base pairs of human mt-DNA. This new mt-DNA model has been preliminarily tested in this work by determining SSB and DSB DNA damage yields and site-hit probabilities due to the impact of proton particles. The accuracy of the geometry was determined by three-dimensional visualization in various ring element numbers. The hit locations were determined with respect to a reference coordinate system, and the corresponding base pairs were stored in the ROOT output file. Results The coordinate determination according to the algorithm was consistent with the expected results. The output results contain the information about the energy transfers in the backbone region of the DNA double helix. The output file was analyzed by root analyzing tools. Estimation of SSBs and DSBs yielded similar results with the increment of incident particle linear energy transfer. In addition, these values seem to be consistent with the corresponding experimental determinations. Conclusions This model can be used in numerical simulations of mt-DNA radiation interactions to perform realistic evaluations of DNA-free radical reactions. This work will be extended to supercoiled conformation in the near future.

In this work, the general purpose Monte Carlo N-particle radiation transport computer code (MCNP-4C) was used for the simulation of X-ray spectra in diagnostic radiology. The electron's path in the target was followed until its energy was reduced to 10 keV. A user-friendly interface named ‘diagnostic X-ray spectra by Monte Carlo simulation (DXRaySMCS)’ was developed to facilitate the application of MCNP-4C code for diagnostic radiology spectrum prediction. The program provides a user-friendly interface for: (i) modifying the MCNP input file, (ii) launching the MCNP program to simulate electron and photon transport and (iii) processing the MCNP output file to yield a summary of the results (relative photon number per energy bin). In this article, the development and characteristics of DXRaySMCS are outlined. As part of the validation process, output spectra for 46 diagnostic radiology system settings produced by DXRaySMCS were compared with the corresponding IPEM78. Generally, there is a good agreement between the two sets of spectra. No statistically significant differences have been observed between IPEM78 reported spectra and the simulated spectra generated in this study.