Introduction: In radiation treatment of stage one seminoma (SOS) induced secondary cancer in organs at risk (OARs), is late toxicity of major concern. This study aimed to compare the secondary cancer risk in radiotherapy of SOS in two-dimensional conventional (2D) radiation therapy and three-dimensional conformal radiation therapy (3DCRT).Material and Methods: CT scan images of 10 patients with SOS were used to design 2D conventional and 3D conformal treatment plans using 25 Gy in 20 sessions. The life attributable risk (LAR) of the liver, stomach, and colon were calculated using the organ equivalent dose (OED) model for organs in the radiation field and the Biologic Effects of Ionizing Radiation VII (BEIR VII) model for organs out of the field.Results: LAR of OARs in radiation fields such as the liver and stomach were obtained 40% higher in the 2D treatment than in the 3D treatment, while as for the colon, it was 17% lower in the 2D treatment than in the 3D treatment. The LAR values of kidneys located outside the radiation field in the 2D treatment were calculated at 0.04%.Conclusion: Increasing the prescribed dose (25 vs. 20) as well as the number of treatment sessions (20 vs. 10) resulted in increase in the LAR of the liver, stomach, and colon. Therefore, estimating the cancer risk of critical organs exposed to radiation through examining the effects of dose fractionation and prescribed doses can be used in optimizing of the treatment plan for seminoma, selecting a better treatment method by oncologists, and patient follow-up.

Introduction: Sometimes, a patient receives a poor quality medical image from a medical imaging center. Which the doctor orders to re-image with a drug contrast media agent. At this time, practical action is challenging to provide a proper image. Cobalt oxide nanoparticles show different activities based on different sizes and shapes. Objectives of this project is achievement a critical size of cobalt oxide nanoparticles between 5 to 10 nanometers for easy circulation in the blood and Investigation of the effect of cobalt oxide nanoparticles on the quality of CT from laboratory mice(Mus musculus).Material and Methods: In this study, the coupling method was used to prepare the cobalt oxide nanoparticles. Co3O4 nanoparticle coatings are used for this purpose. They were investigated through the Fourier-transform infrared (FTIR) analysis, X-rays diffraction (XRD). In order to investigate the efficacy of cobalt oxide nanoparticles, we injected a suspension into the Mus musculus, and then the computerized tomography (CT) scans were taken before and after injection of the nanoparticles. Then, quantity evaluation was performed using the calculating the average local contrast media of the whole image.Results: The average size of cobalt oxide nanoparticles was obtained about 5.8 nm, which is an appropriate size in the nanometer scale. After injecting of cobalt oxide nanoparticles into the mice and then CT scan imaging, we have obtained a better clarity.Conclusion: Cobalt oxide nanoparticles behave well for use as a pharmacological contrast media agent in CT scan imaging.

Introduction: This study aimed to investigate the absorbed dose of scatter radiation in coronary angiography. Materials and Methods: The scatter radiation dose was measured for 20 patients at four different heights (50,100, 150 and 165 cm) from the floor. Spatial dose was measured by RTI Piranha r100b solid state dose probe at different points around the patient in actual clinical situation and with phantom. Also the measurement was repeated using a designed phantom in fluoroscopy and cine mode in PA, LLAT, LPO, RAO and RLAT projections. The dose to dose area product (DAP) conversion coefficients for each organ were calculated. Results: The dose rate at different heights between the projections on the patient and the phantom as well as organ dose DAP conversion coefficients were different (p˂0.05). It was found that the dose rate changes in fluoroscopic mode compared to cine mode are significantly different (p = 0.001). The dose rate in cine mode is approximately four times of that in fluoroscopy mode. The dose rate around the cardiologist waist could be reduced by 37 – 43 % with a displacement of 20cm away. Conclusion: Taking a suitable projection could indeed reduce the dose rate delivered to the angiography team. In this study, the effective dose rate received by the cardiologist’s eyes was higher than those reported by ICRP.

Introduction: Computed Tomography (CT) is nowadays used widely to differentiate normal brain cranium sutures from abnormal ones in pediatric patients with the aim of early treatment. This study tried to develop a low-dose CT protocol with the acceptable image quality of skull bone in order to evaluate craniosynostosis. Material and Methods: In this study a cranium bone of human cadaver was scanned with standard and reduced dose protocols. Two radiologists verified the quality of skull bone images acquired from the protocol in which there had been 60 dose reduction to scan pediatric patients. The quality of low dose protocol of three dimensional (3D) CT images of skull bone of 57 pediatric subjects suspected of craniosynostosis were compared with standard-dose skull CT images of 44 patients of the same age range. Volume CT dose index (CTDIvol), dose-length product (DLP), and effective dose (ED) were used to evaluate CT dose protocols. The comparison was made by two sample t-test. Results: Mean and standard deviations of CTDIvol, DLP, and ED of standard and reduced doses were 12.4±2.7 mGy, 191.5±54 mGy.cm, 1.94±0.58 mSv and 5.4±0.2 mGy, 85±9 mGy.cm, 0.77±0.17 mSv, respectively, which had statistically significant difference (α=0.05). The quality of skull bone views obtained from low-dose CT protocol were found to be as good as in standard dose. Conclusion: Standard-dose 3D CT protocol of skull bone can be replaced by a 60-reduced-dose 3D CT protocol with comparable image quality in pediatric patients suspected of craniosynostosis.

Introduction: After lumpectomy, radiation therapy is used to control the tumor and increase patient survival. Following radiation therapy, the organs at risk are vulnerable to toxicity and secondary cancer. Material and Methods: Thirty-two patients with early-stage of left breast cancer were selected for this study. Intensity-modulated radiotherapy (IMRT) and three-dimensional conformal radiotherapy (3DCRT) were planned to deliver the prescribed dose to the target volume. Considering baseline risk of heart disease, the excess absolute risk (EAR) of heart disease was calculated using the Reynolds risk score for ages 50-70. Results: There was a significant difference in 10-year EAR of heart disease when comparing 3DCRT plans to IMRT (p <0.05). The 10-year EAR for IMRT in the low, median, and high-risk groups was superior to 3DCRT. Among factors involved in baseline risk, by increasing the age, the impact of smoking on increasing EAR was clearer compared to a family history of heart disease. Conclusion: IMRT had a more uniform dose distribution and a better conformity-homogeneity index than 3DCRT. However, the mean heart dose and subsequently the risk of heart disease significantly were lower in 3DCRT. Considering baseline risk leads to accurate estimates of the heart disease risk after breast cancer radiotherapy.

Introduction The large number of coronary angiography procedures and inappropriate use of radiation protection equipment constitute a high occupational radiological risk for cardiologists generated by chronic exposure to low doses of radiation, in particular for parts of the body unprotected such as eyes and head. Materials and methods The eye lens dose was evaluated for seven cardiologists performing coronary angiography procedures over three months. The equivalent dose to the eye lens, Hp (3), was calculated from the equivalent dose to the skin, Hp (0.07), measured by an active dosimeter worn at the cardiologist's neck. The annual eye lens dose and the brain cancer risk were estimated. The correlation between the eye lens dose and the procedure parameters including the dose-area product, the fluoroscopy duration, and the number of fluography images was studied. Phantom-based measurements by a babyline 81 allowed to separate the contribution of the two modes, fluoroscopy and fluorography to the total dose and therefore, to propose another method of continuous lens dose monitoring. Finally, an optimization study was performed to reduce the eye lens dose and consequently the brain cancer risk. Results Two cardiologists have exceeded the annual lens dose limit (28mSv, 22mSv). A good correlation was found between Hp (3) and the fluoroscopy duration (R² = 0.89). The measurements showed that most of the exposure was in fluoroscopic mode (89%). The optimization study reduced the annual eye lens dose to 2.9 mSv and 2.3 mSv, respectively, for these two cardiologists. Thus, this decreased the brain cancer risk by a factor of ten. Conclusion The high eye lens annual doses recorded in this study are due to non-compliance with radiation protection rules. The proposed optimization process reduced the eye lens dose and the risk of brain cancer, at least, by a factor of ten.

Introduction: The importance of estimating patient-sized adjusted radiation dose for pediatric computed tomography (CT) has long been accepted. High doses of ionizing radiation to children are often common in chest CT examinations, as the volume CT dose index (CTDIvol) is measured by a 32 cm phantom. Our study aimed to evaluate the effectiveness of size-specific dose estimate (SSDE) to compensate for the underestimated pediatric absorbed dose. Material and Methods: CTDIvol and dose-length product (DLP) of 320 pediatric chest CT (&lt;1, 1-5, 5-10, 10-15 years) were obtained from Picture-Archiving and Communication System (PACS) in a hospital affiliated with the Shiraz University of Medical Sciences. CTDIvol was converted to SSDE based on the patient's effective diameter. The Statistical Package for Social Science (SPSS) was used for data analysis. Results: The variations between standard phantom (32cm) and the patients' mean effective diameter were approximately 65, 57, 47, and 38, across &lt;1, 1-5, 5-10, 10-15 year age groups, respectively. The mean of SSDE for each age group was significantly higher than the corresponding CTDIvol values. Also, mean CTDIvol and SSDE values differed between age groups significantly (p&lt;0.001). Results showed a strong correlation between age and the two-dose indicators, CTDIvol (0.361) and SSDE (0.184), with p&lt;0.05. Conclusion: Pediatrics receive radiation doses comparable to the dose for adult-sized patients in chest CT protocol if the dosimetry procedure is not individualized. Thus, applying a size-based conversion coefficient is paramount in estimating the absorbed dose in pediatric chest CT

Introduction: The purpose of this study is to evaluate and compare treatment plan quality metrics for postmastectomy breast cancer patients using 3-Dimensional conformal radiotherapy (3DCRT) and intensity-modulated radiotherapy (IMRT) planning techniques.Material and Methods: The current study included 50 postmastectomy breast cancer patients out of which 24 were planned with 3DCRT and 26 with IMRT technique. Treatment plan quality metrics, namely homogeneity index (HI), conformity index (CI), conformation number (CN), uniformity index (UI) and spillage index (R50), volume receiving 110% and 95% of the prescribed dose (V110% and V95%) were calculated and compared for the two planning techniques.Results: IMRT plans have better conformity, homogeneity indices, and lower V110% than 3DCRT plans with an almost similar R50% and V95%.Conclusion: Quantitative values of radiotherapy treatment plan quality metrics for the target are found in favour of the IMRT technique rather than 3DCRT. Implementation of these five parameters is helpful for evaluating treatment plans along with slice by slice and DVH analysis.

Introduction: The study aimed to provide the dose accuracy effects between the Anisotropic Analytical Algorithm (AAA) and the deterministic solver Acuros XB (AXB) that are available on Eclipse TPS (Varian Medical Systems, Palo Alto, CA) treatment planning system (TPS). The purpose is to investigate the difference between the AAA and Acuros XB Algorithm, The difference is due to the electron transport difference in the case of small fields. Material and Methods: For the study of non-small cell lung cancer (NSCLC) patient Computed tomography (CT) scans are used to do retrospective stereotactic body radiosrgery (SBRT) plans via AAA and recalculated by AXB dose calculation algorithms using the Eclipse treatment planning system. The main dosimetric comparison parameters are Conformity index (CI), Homogeneity Index (HI), Gradient Index (GI), Target mean dose, and calculation time. The Statistical analysis done by the gamma index comparison. Results: Based on the results, the CI is (1.45±0.55) to (1.85±0.7) (P<0.05). The HI are (0.15±0.07) and (0.13±0.08) (P<0.05), the GI for AAA was (4.8±2.6) and for AXB reaches (7.4±3.8) (P<0.05) and the maximum dose for Planning target volume (PTV) is differed about 2.3% to 4.5%, mean dose is differed about 2.4% to 3.8% and the calculation time 153±43sec and 185±76sec for AAA and AXB respectively. Conclusion: The findings using the deterministic solver AXB in the calculation for the case of low density like lung cases is more accurate than AAA calculation Algorithm in SBRT treatment.

Purpose: The aim of this study is to estimate local DRL values for computed tomography (CT) procedures, corresponding to Head, Chest, and Abdomen-Pelvis examinations (single acquisition), in Moroccan hospitals.Methods: A total of 1917 diagnostic CT examinations were included in this study. Firstly, we analyzed the CT dose indicators CTDIvol and DLP of all the examinations collected. Although we have proposed local diagnostic reference levels just for: head, thorax, abdomen-pelvis, due to the lack of data for the other examinations. Furthermore, we calculated the effective dose for chest examination using CT-expo software to estimate effective and organ dose for chest CT.The results: showed that the estimated local DRLs using CTDIvol are 48 mGy, 14 mGy, and 12 mGy for head, chest, and abdomen-pelvis respectively, and 986 mGy.cm, 496 mGy.cm, and 651 mGy.cm for DLP, respectively.Conclusion: This work establishes local DRLs for CTDIvol and total DLP for head, chest, and abdomen-pelvis procedures and proposes chest effective doses for adult patients. The study shows that the results are conforming to the literature.