Background: Breast is one of the main radiological sensitive organs, hence it is important to evaluate ABSORBED DOSE to this organ especially to the GLANDULAR parts. It is the aim of this study to measure mean GLANDULAR DOSE and image contrast in terms of different mammographic parameters. Materials and Methods: In this study two mammography machines located at Said-al Shohada (Giotto) and Shahid Behesti (GE) hospitals were used. According to the recommendations of ACR and MQSA, breast phantoms were constructed and used for this study. For DOSE evaluation TLD dosimetry method was used. The TLD dosimeters were of LiF type and the reader was a Solaro TLD reader. Results: To obtain a constant contrast when increasing kVp from 22 to 24, it was necessary to reduce mAs by 12 percent. The obtained relation between these two parameters is: contrast=0.2829D-0.2427. It was also found that there is a linear relationship between contrast and image quality. The relation between these two parameters is: Image quality=28.117 Contarst+20.134. Increasing kVp and hence decreasing mAs results a reduction to the GLANDULAR DOSE, especially in patients with large breast. Increasing kVp from 28 to 30 results in reduction of DOSE from 6.8mGy to 5mGy. Conclusions: It was found that there has been a linear relationship between contrast and image quality. It was also found that increasing kVp necessitate to reduce mAs for a constant contrast and hence reduction of GLANDULAR DOSE.

Background: In this work a new method for the Mean GLANDULAR DOSE evaluation in digital breast tomosynthesis (DBT) is presented. Methods: Starting from the experimental-based dosimetric index, 2ABD, which represents the average ABSORBED breast DOSE, the mean GLANDULAR DOSE MGD2ABD was calculated using a conversion function of GLANDULARity f(G), obtained through the use of Monte Carlo simulations. Results: f(G) was computed for a 4. 5 cm thick breast: from its value MGD2ABD for different compressed breast thicknesses and GLANDULARities was obtained. The comparison between MGD2ABD estimates and the dosimetric index provided in the current dosimetry protocols, following the Dance's approach, MGD Dance, showed a good agreement (<10%) for all the analyzed breast Dance thicknesses and GLANDULARities. Conclusion: The strength of the proposed method can be considered an accurate mean GLANDULAR DOSE assessment starting from few and accessible parameters, reported in the header DICOM of each DBT exam.

Introduction: Average GLANDULAR DOSE calculation in mammography with Mo-Rh target-filter and DOSE calculation for different situations is accurate and fast.Material and Methods: In this research, first of all, x-ray spectra of a Mo target bombarded by a 28 keV electron beam with and without a Rh filter were calculated using the MCNP code. Then, we used the Sobol-Wu parameters to write a FORTRAN code to calculate average GLANDULAR DOSE.Results: Average GLANDULAR DOSE variation was calculated against the voltage of the mammographic x-ray tube for d=5 cm, HVL=0.35 mm Al, and different value of g. Also, the results related to average GLANDULAR ABSORBED DOSE variation per unit roentgen radiation against the GLANDULAR fraction of breast tissue for kV=28 and HVL= 0.400 mmAl and different values of d are presented. Finally, average GLANDULAR DOSE against d for g=60% and three values of kV (23, 27, 35 kV) with corresponding HVLs have been calculated.Discussion and Conclusion: The ABSORBED DOSE computational program is accurate, complete, fast and user friendly. This program can be used for optimization of exposure DOSE in mammography. Also, the results of this research are in good agreement with the computational results of others.

Introduction: Assessment of radiation DOSE is an important task in radiation protection dosimetry whereas ABSORBED and effective DOSE measurements directly in body organs are impossible. So Monte Carlo simulations is necessary to estimate radiation DOSE. The method of DOSE calculation, the body model and the computational code can be mentioned as three main factors that have an affect on dosimetric quantities. The aim of this study is the determination of the above factors influence on the ABSORBED DOSE and effective DOSE evaluation. For this purpose different comparisons between the mathematical and the voxel phantoms were done.Methods: ORNL modified adult phantom is the mathematical phantom which is described by Cristy and Eckerman in 1987. This phantom is utilized for calculation of the ABSORBED DOSE. The effective DOSE is calculated according to the manner which is introduced in the ICRP reported 60 and 103.Results: All of the DOSEs Evaluation have an uncertainty less than 0.5%. MCNPX code and ORNL modified adult phantom are applied for the DOSE assessment in the energy range 10-9 – 20 MeV, under AP, PA, RLAT, LLAT, ROT and ISo irradiation conditions. The results are then normalized to the unit of neutron fluence. The calculated ABSORBED DOSE was compared with ICRP74 data in 9 organs and with Bozkurt et al data in 18 organs. The effective DOSE was calculated for whole body. Then these data were compared with results of a mathematical phantom and some voxel models in different irradiation geometries.Conclusion: Although the ABSORBED DOSE results of ORNL show fewer differences with ICRP data than Bozkurt et al data, one can deduce neither complete agreement nor disparity between the ORNL data and the other two data sets. Totally 73% of the ORNL data in comparison with MIRD data and 48% of data in comparison with VIP_MAN results have difference less than 15%. Comparison of the ORNL effective DOSE with some male and female voxel phantoms (TARA, HANAKO, GSF, VIP_MAN) and an analytical model (MIRD) show that the changing of body model and computational code have few influence (less than 15%) on the effective DOSE results. But changing of wR and wT parameters have a significant effect on the results so that the largest discrepancies are about 100% on some data.

Radiation damage depends on energy absorption, and is approximately proportional to the ABSORBED energy density in the tissue. In external radiation consideration with a certain energy flux, the amount of ABSORBED DOSE in each point of the tissue depends on the type of radiation, the radiation energy, the depth of the place of receipt, and the main components of the absorber environment. The ABSORBED energy in tissue is important in radiotherapy. This issue is well known for ionizing radiation such as X and Gamma, and is implemented in therapeutic protocols. But less attention is paid to laser therapy. Due to the actual risks of laser use, dosimeters in laser therapy are very important, in addition to observing the permissible radiation limits, in terms of radiation protection, radiation DOSE is required to achieve the desired effect from the requirements of this laser application in medicine.

Given the extensive use of common mammography tests for screening and diagnosis of breast cancer, there are concerns over the increased DOSE ABSORBED by the patient due to the sensitivity of the breast tissue. Thus, knowing the Mean GLANDULAR DOSE (MGD) before radiation to the patient through its estimation can be helpful. For this reason, the MultiLayer Perceptron (MLP) neural network model was trained with Levenberg-Marquardt (LM) backpropagation training algorithm and the Entrance Surface Air Kerma (ESAK) was estimated. After running the program, it was found that 35 neurons is the most optimal value, offering a regression coefficient of 95. 7%, where the Mean Squared Error (MSE) for all data was 0. 437 mGy, accounting for 4. 8% of the range of output changes, representing a prediction with 95. 2% accuracy in the present research. In comparison with the Monte-Carlo simulation method, it enjoys a desirable accuracy.

Background: Accurate computation of the radiation DOSE to the breast is essential to mammography. Various the thicknesses of breast, the composition of the breast tissue and other variables affect the optimal breast DOSE. Furthermore, the GLANDULAR fraction, which refers to the composition of the breasts, as partitioned between radiation-sensitive GLANDULAR tissue and the adipose tissue, also has an effect on this calculation. Fatty or fibrous breasts would have a lower value for the GLANDULAR fraction than dense breasts.Breast tissue composed of half GLANDULAR and half adipose tissue would have a GLANDULAR fraction in between that of fatty and dense breasts. Therefore, the use of a computational code for average GLANDULAR DOSE calculation in mammography is a more effective means of estimating the DOSE of radiation, and is accurate and fast.Methods: In the present work, the Sobol-Wu beam quality parameters are used to write a FORTRAN code for GLANDULAR DOSE calculation in molybdenum anode-molybdenum filter (Mo-Mo), molybdenum anode-rhodium filter (Mo-Rh) and rhodium anode-rhodium filter (Rh-Rh) target-filter combinations in mammograms. The input parameters of code are: tube voltage in kV, half-value layer (HVL) of the incident x-ray spectrum in mm, breast thickness in cm (d), and GLANDULAR tissue fraction (g).Results: The average GLANDULAR DOSE (AGD) variation against the voltage of the mammogram X-ray tube for d = 4 cm, HVL = 0.34 mm Al and g=0.5 for the three filter target combinations, as well as its variation against the GLANDULAR fraction of breast tissue for kV=25, HVL=0.34, and d=4 cm has been calculated. The results related to the average GLANDULAR ABSORBED DOSE variation against HVL for kV = 28, d=4 cm and g= 0.6 are also presented. The results of this code are in good agreement with those previously reported in the literature.Conclusion: The code developed in this study calculates the GLANDULAR DOSE quickly, and it is complete and accurate. Furthermore, it is user friendly and useful for DOSE optimizing in mammography imaging.

Objective: Cosmic radiations from outer space are continuously exposing the earth. Ambient DOSE rate at the atmosphere, apart from unusually and transient solar activities, is mostly a function of latitude and altitude. At aircraft altitude and temperate latitudes, it increases by a factor of 20-25. Therefore, aircrew and frequent flyers are exposed to high levels of cosmic radiation. This paper considers general radiation protection aspects of cosmic radiation exposure to aircrew in domestic flights in Iran.Materials and Methods Ambient DOSE rate in several domestic flights was measured using survey meter model RDS-110. Based on the measured data and duration of the flight, the effective DOSEs of the aircrew were calculated and compared with that derived from radiation transport codes of CARI-6 introduced by Civil Aerospace Medical Institute, Oklahoma City, USA. Due to good agreement between measured and calculated values, the CARI-6 program was used to determine the DOSE rates in different altitude throughout the country to provide a simple algorithm for calculating route DOSE in domestic flights.Results: Equivalent DOSE rate in domestic flight's altitude can be calculated from, a(h)b where h is the altitude in thousand feet; a and b are constants depending to geographic location. Based on the equivalent DOSE rate and the flight profile; simple algorithm provided to estimate the route DOSE in any domestic flights.Conclusion: The annual DOSE limit of general population allows the aircrew to spend 290 hour in 27-33 thousand feet altitude in domestic flights; therefore, only female aircrew should be made aware of the need to control DOSEs during pregnancy.

Objective: Radiotherapy is one of the methods used in cancer treatment. In this method tumor cells are exposed to ionizing radiation to kill these cells. More of tumor cells are killed if exposed more radiation within the region of tumor. However, the main purpose of radiotherapy is exposing enough DOSEs to tumor mass yet protecting the normal tissues around it. In this study, we investigate the effect of temperature on the ABSORBED radiation DOSE.Materials and Methods: In these experiments a 30 ×30 × 30 cm water phantom, Farmer ionization chamber and related electrometer were used to measure the effects of exposing g_radiation of Co-60. The field size was varied for (5×5 cm2 to 20×20 cm2) with depths (5 to 9 cm) and the range of temperatures (30 to 50oC). The curves for variation of ABSORBED DOSE at different depth at different temperatures were drawn and a temperature enhancement ratio (TER) was introduced. Results: Our results showed that TER increases for all field sizes and depths with increase in temperature. A pronounced effect was observed at temperatures higher than 42oC.Conclusion: These findings suggest that the hyperthermia (above 42oC), caused a sudden variation of the structure of water and increased the absorption of radiation DOSE.