Paramedical Sciences and Military Health

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Introduction and purpose: The aim of this study is introducing a new Mono-Isocentric Technique)MIT) for external  radiotherapy of the chest wall in the mastectomy patients with 6MV photon beams and comparing this technique with the Dual-Isocentric Technique(DIT).

Materials and methods: Data of 18 mastectomy patients having chest wall radiotherapy were used. The target tissue was divided into nine regions with 17 points as the appropriate candidates to find the appropriate dose calculation reference point for the MIT. Dose calculations were made for each patient based on the MIT and DIT to determine the dose distributions of the target volume and organs at risk after finding the dose calculation reference point.

Findings: The lateral component of the dose calculation reference point was found to be located at one-third of the distance between the geometrical center and the lateral border of the chest wall in the lateral direction toward the outer border. The longitudinal component of this point was found to be located at the geometrical center of the chest wall with a depth located around 2–3 cm under the patients’ skin. There was no significant difference between the two radiotherapy planning techniques regarding the dose distri­butions in the organs at risk and the 95% of the prescribed dose coverage of the target tissue. However, a significant difference for the 105% of the prescribed dose coverage, maximum dose delivered to the target tissue was found, with the DIT showing higher values

Discussion and conclusion: Because of the good matching and no superposition observed between the treatment fields in the MIT, it was expected and confirmed that the regions with higher and lower doses than the prescribed dose with the MIT are significantly fewer than that of the DIT. Therefore, to perform a better conformal radiotherapy for the patients having mastectomy, it could be recommended to use the MIT instead of the DIT and other conventional techniques.

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Introduction: One of the problems that exists in the quality control procedure of the treatment planning systems and the computer simulation of the radiotherapy or diagnostic radiology validation is comparing the dose distribution resulted from the dose calculation algorithms with the experimental results(as a reference). For this purpose, several methods have been proposed to compare these dose distributions and determine the amount of the similarity or differences quantitatively. The dose difference (DD), distance to agreement (DTA) or the combination of these two parameters named gamma evaluation and these methods are the common methods for this purpose. Ignoring the factors related to the irradiation and disallowing the differences between the different regions in the dose distribution are the most important problems of these methods. The aim of this study is to providing a novel method which is able to consider mentioned factors and differences during the comparison procedure.   

Materials and Methods: According to previous studies, 4 different regions and 3 different irradiation conditions was defined for the dose distribution and irradiation mode respectively. Special restrictions in the DD and DTA were considered for each couple of the region-irradiation condition. In each region of dose distribution gamma evaluation equations was defined according to these restrictions and dose comparison was performed as region to region in all regions of the dose distribution.

Results: Weighted gamma evaluation algorithm was obtained and proposed table related to the DD and DTA restrictions was written.  

Discussion and conclusion: Due to the related and relevant equations for any region of the dose distribution in the weighted gamma evaluation method, it is expected that this method will show a clinically better results compared to the common methods.

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Introduction: Individual exposure after a nuclear detonation (atomic bomb) delivers abundant doses with high dose rates to the people who were located near the nuclear detonation location or within the fallout zone. Effects of the radiation to the humans and animal models will be studied and a fundamental ground work of medical services and managing systems for such
accidents would be provided in this article.
Methods and Materials: This research is theoretical and analytical method that was performed by searching care proceedings, nuclear detonation, radiobiological effects, acute radiation syndrome and radiation accidents key words in the Google Scholar, Science Direct, PubMed and Scopus web sites in terms of content (Content Analysis). This article was written based on the 10 chosen articles which were found after the research in the internet web sites.
Results: Whole-body doses >2 Gy which was found in the fallout zones or in the areas near the detonation location, can produce clinically significant acute radiation syndrome (ARS)(definite radiation effects), which classically involves the hematologic, gastrointestinal, cutaneous, and cardiovascular/central nervous systems. The severity and presentation of ARS are affected by several factors, including radiation dose and dose rate, inter-individual variability in radiation response, type of radiation (e.g., gamma alone, gamma plus neutrons), partial-body shielding, and possibly age, sex, and certain preexisting medical conditions. The combination of radiation with trauma, burns, or both (i.e., combined injury) confers a worse prognosis than the same dose of radiation alone. Supportive care measures, including fluid support, antibiotics, and possibly myeloid cytokines (e.g., granulocyte colony-stimulating factor), can improve the prognosis for some irradiated casualties. Available resources for the supportive and therapeutic cares were far less than demands of the extents of injuries and access to these resources for the patients and injured people will be very limited during the nuclear detonations and its consequences.
Discussion and Conclusion: Because of the leakage and hard limitations in the resources availability for supportive and medical cares, it will be impossible to apply these cares and services for all of the patients and injured people after the nuclear detonation. It is necessary to determining the patients who must receive these cares. It is more appropriate to evaluate the absorbed dose of the all injured people by applying the biological dosimetry methods. Regarding to the patient symptoms and absorbed dose, type of the ARS syndrome will be determined. After the patients division, selected patients will be undergoing medical and supportive cares. For optimal use of available resources it is necessary to provide a general plan for doing these cares and services, guidance for training people who want to do medical and supportive cares for the radiation injured patients and building a database of the radiation accidents injured patient’s data. Long term radiobiological effects such as the cancer, teratogenesis, and heritable genetic effects were not evaluated and just initial effects of radiation were discussed in this study.

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Introduction: Nowadays, we are witnessing a progressive application of radiology techniques in various communities as well as in Iran. Medical radiological examinations are one of the important sources of public radiological dose. Entrance skin doses and effective doses for patients in diagnostic radiology examinations should be assessed for the imaging techniques optimization and patient’s radiation protection. Thus, the related radiation-protection organizations have recommended measuring the patient doses resulted from such techniques. The main purpose of this study was to investigate the patient doses in common radiographic examinations.

Methods and Materials: The eight most commonly radiology examinations were selected for dosimetry calculations after reviewing and analyzing radiology examination data at an imaging center over a 3-month period. 283 patients underwent eight radiography procedures containing Chest (PA), Pelvice (AP), Abdomen (AP), Skull (AP), Thoracic Spine (AP), Thoracic Spine (LAT), Lumbar Spine (AP) and, Lumbar Spine (LAT) were selected for dose measurements. Data of exposure parameters (kVp, mAs, FFD and projection) were collected in all 283 patients. ESD (Entrance Skin Dose) and effective dose values were calculated using the analytical formula and a software indirectly (PCXMC). In addition, they compared with published works and internationally established diagnostic reference levels.

Results: The average entrance skin dose (in mGy) and effective dose (in mSv) for the Chest (PA), Pelvice (AP), Abdomen (AP), Skull (AP), Thoracic Spine (AP), Thoracic Spine (LAT), Lumbar Spine (AP) and, Lumbar Spine (LAT) were (0.15-0.028), (5.4-0.87), (2.7-0.61), (2.2-0.05), (4.6-0.28), (5.1-0.20), (5.8-0.47), (6.2-0.30), respectively.

Discussion and Conclusion: As expected, the patient doses in radiology exams varied consumedly because it depends on many factors including the type of medical imaging systems, examination complexity, experience and skill of the operator, and patient’s weight. In radiology, it is possible to reduce patients’ effective dose using small field of views, appropriate potential difference and mAs. There is still a need for personnel training and national guidance on good
practice for optimizing of patients’ doses.

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Introduction: Cardiac CT (Computed Tomography) angiography applies as a pre-exam method for evaluating the patients with medical problems in their cardiac arteries. Due to the high delivered dose in this imaging method, dose reduction techniques and imaging strategies that serve the images quality with minimum patient dose are the subjects for investigation and research studies. This study will evaluate and discuss the clinical aspects and dose reduction techniques in cardiac CT angiography briefly.

Methods and Materials: This research is theoretical and analytical method that was performed by searching “cardiac CT angiography, radiation protection, and patient’s dose reduction methods” key words in the Google Scholar, Science Direct, PubMed and Scopus web sites in terms of content (Content Analysis). This article was written based on the 10 chosen articles which were found after the research in the internet web sites.

Results: Various applied techniques like tube current control using ECG (electrocardiogram), X-ray tube voltage reduction, scan sequence changing methods, greater detector coverage and working modes with higher pitches are available in cardiac CT angiography for reduction in the delivered dose to the patients.

Discussion and Conclusion: Several applied strategies are available for dose reduction in cardiac CT angiography in daily applications. Most of these dose reduction strategie which are useful in many patients can be used in most of the clinical cases. Nowadays, many of techniques using dose saving algorithms were presented commercially. It is very essential and important to adapt the scan protocol with any possible dose reduction strategy for every patient as mentioned in the American heart institute scientific meeting in 2008. Combination of several dose saving algorithms are usually feasible and cause to more effective dose reduction in cardiac CT angiography.

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Introduction: The use of ionizing radiation in diagnosis and treatment of diseases has become inevitable in most medical branches. One of the important sections in medicine is orthopedic surgery room, which also serves to operate many of bone injuries. The aim of this study was to measure the delivered doses to the patients undergoing orthopedic surgeries in common and high usage radiographic imaging techniques.

Methods and Materials: In this study, delivered doses to 81 patients (58% male, 42% female) underwent four orthopedic radiography examinations including intramedullary nailing (IMN), intertrochanteric/peritrochanteric (IP), Dynamic Hip Screw(DHS) and Dynamic Cannula Screw(DCS) was estimated at a general hospital in Tehran, using indirect measurements and Monte Carlo simulations base on the peak kilo-voltage, electrical current (mA), time of the irradiation (sec), exposure angle, imaging region and size of the patients.

Results: The average effective dose measured for IMN, IP, DHS and DCS examinations were estimated equal to 0/95, 1/31, 2/22, 0/95 (mSv ) respectively. The mentioned values were calculated just for one radiography procedure, although in real orthopedic surgical operations, the number of radiographies can differ from 5 to 20 with respect to the physician and radiation technician proficiency, method of the operation and type of the injuries. So the delivered effective dose to patients can have much higher values than mentioned above.  

Discussion and Conclusion: The patients delivered dose had great variations between different patients and techniques, because it depends on many factors including the type of medical imaging systems, examination complexity, region of imaging, physician and technician skills and patient weight. It is possible to reduce patients’ effective dose by using small field of views, appropriate potential difference, time of irradiation and electrical current. There is still a need for personnel training and national guidance for optimizing the patients’ doses.

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Introduction: Digital Subtraction Angiography (DSA) is the standard method for detection of carotid artery stenosis. This technique has high radiation dose. With the progress of imaging techniques, noninvasive or minimally invasive methods like the CT angiography, MR angiography and ultrasonography with Doppler or Duplex mode were applicable. This study aimed to evaluate and assesse the results of Doppler ultrasonography in comparison with the
DSA in diagnosis of internal carotid artery.
Methods and Materials: 20 male patients with internal carotid stenosis > 50% who previously underwent the DSA examination, were examined with the Doppler ultrasonography. Obtained Structural and hemodynamic parameters from Doppler ultrasonography were analyzed regarding to German Society of Ultrasound in medicine and NASCET recommendations. The degrees of carotid stenosis resulted from the Doppler ultrasonography were evaluated and compared with the DSA results.
Results: Doppler and DSA findings did not show significant differences (P<0.05). The mean values of internal carotid artery stenosis were 69.8%, 67.9% and 71.3% for Doppler ultrasonography using German society of US in medicine recommendations, Doppler ultrasonography using NASCET recommendations and DSA results respectively. Sensitivity values of Doppler ultrasonography in comparison with DSA results were 94.5% and 95.2%, and specificity values were 96.7% and 97.1% for German society of US in medicine and NASCET, respectively.
Discussion and Conclusion: The Doppler ultrasonography had high precision, sensitivity and specificity in our study. This method can be used as a noninvasive and easy to use technique in detection and determination of this disease especially in patients who don’t need angioplasty procedures.

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Introduction: Radiation protection of patients, personnel and other people is very important in medical imaging using ionizing radiation (such as X-rays and gamma rays). These radiations can cause various biological damages such as carcinogenesis, cataracts, embryonic injuries. Therefore, the knowledge of radiation protection of radiation workers is very important and the purpose of this research is to assess the radiation protection knowledge of radiology technologists in military hospitals in Tehran.
Methods: This research is descriptive-analytic and cross-sectional study. A questionnaire about the knowledge, attitude, and performance of radiation protection was distributed among the 80 radiation technologists of Tehran’s military hospitals. The data of the completed questionnaires were analyzed using one-way ANOVA, sample t-test and Spearman/Pierson correlation tests in SPSS-19 software.
Results: The mean of the obtained radiation protection knowledge score was 11.20 ± 4.28 out of 20. There was no significant difference between the radiation protection knowledge, performance knowledge and motivation among graduates of AJA and other universities as well as between men and women. There was a very weak correlation between age with knowledge of radiation protection and performance as well as between education with knowledge of radiation protection, performance knowledge and motivation.
Conclusion: Comparison of our investigation results with previous studies showed that the level of radiation protection knowledge of Army Radiology technologists is low. It was also determined that age, gender, and work experience had no effect on the functional knowledge and radiation protection knowledge, nor did it have an impact on knowledge, performance and motivation with increasing educational level.