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Objective: Over 1/3 to half of accurate medical diagnosis are based on x-ray examinations. The x-ray tube is the main part of a radiology set. X-ray production is a phenomenon with low efficiency and over 99.6% of the fast electrons energy changes to heat. This heat is also a limiting factor for the system function. The aim of this study was to design and manufacture an automatic heat control system in radiology tubes for multiple exposures. These exposures are allowed with regard to overload system but inappropriate intervaling in exposures causes heat damages in anode. Methods: The hardware of system was designed and manufactured by using of micro-controller system. Its software was written by 8051 Franklin preview software package and on the basis of anode cooling chart data and installed on micro-controller by A1-11 system. Findings: The designed system can calculate and display anode heat at every moment. Functioning test in 100 experimental exposures showed a reliability of 99.92±0.07%. Conclusion: This system can be used as a suitable equipment in protecting and preventing radiology tubes against heat damages after frequent exposures.

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BACKGROUND AND OBJECTIVE: Health care system is organized at three levels in order to increase efficacy and effectiveness and create justice and also people availability. Considering three levels of primary health care, access of people to specialized services through referral system is possible. With regard to the importance of referral system in family physician program, this study was performed to evaluate the function of referral system and network system of medical universities in Northern provinces of Iran.
METHODS: This analytic study was performed in Autumn of 2008. Twenty percent of health centers (108 centers from 521) which implement the family physician program and rural insurance coverage by medical Universities of Golestan, Mazandaran, Babol and Guilan were randomly selected. In each center 5-7 patients who were referred to level 2 by their family physician and received necessary services were evaluated. They were at their homes at inquiry time.
FINDINGS: From 675 patients who received the level 2 services, 440 cases (65%) were female and 235 (35%) were male. Two hundred and seventy cases (40.5%) had referral form from health house. Only 311 (46%) persons referred because of diagnosis of family physician and in 212 (32.9%) of cases, the family physician had a role to choose a specialist of level 2. For 189 (28.1%) of cases, the specialists wrote the results of their evaluation in feedback form. Only 163 (24.5%) of patients returned to their family physicians. Three hundred ninety-four (79.6%) of patients didn return to their family physician because of lack of knowledge.
CONCLUSION: The results of this study showed that many principles for referral system from level 1 to higher levels and vice versa are not considered that require education, reformation and intervention in this field.

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BACKGROUND AND OBJECTIVE: Breast cancer is the most common cancer in women worldwide and radiotherapy is the best treatment choice after mastectomy. One of the main aims of radiotherapy is applying the uniform dose distribution in all treatment volume. The objective of this study was to evaluate the chest wall angle by reference axis (vertical and horizontal) and use optimum wedge filter in post-mastectomy radiotherapy.
METHODS: One hundred and forty cases of breast cancer after mastectomy surgery were included in this study. Patients were planned by ALFARD treatment planning system (TPS) or three-dimensional (3D) CorePLAN Treatment Planning System (TPS). Dose Volume Histograms (DVHs) with different wedge angles and without wedge were obtained for every case. DVHs were analyzed and compared for finding optimum wedge angle. Chest wall angle with reference axis was determined by GetData software. The wedge angel and chest wall angel were compared to reach the equation between them.
FINDINGS: The optimum wedge angle was the function of chest wall angles. In all cases the compensating wedge filter causes better homogeneity index and results of chest wall angle determination were in good agreement with the results of DVHs as gold standard for determining homogeneity index.
CONCLUSION: Finding of this study showed that an improved chest wall angle in mastectomy patients is a new method for choosing optimum wedge angle. Also time cost of this method is better than DVH technique.

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BACKGROUND AND OBJECTIVE: Cancer is the third main cause of death in Iran after coronary heart disease and accidents. Age pattern of the cancer incidence and its distribution is related to regional conditions, nutritional habits, and environmental, physical and genetic factors. The aim of this study was to determine the age and sex pattern of cancer incidence and also classification of the different types of cancers among patients who referred to Shahid Rajai radiotherapy center Babolsar, Iran.
METHODS: The study was a retrospective research. Data were obtained by the review of patients documents in Shahid Rajai radiotherapy center during 2000-2009. Data included demographic variables, and type of the cancer. The types of cancer were classified and assessed on the basis of International manual classification of diseases (ICD).
FINDINGS: During the 10-year study period, 8307 patients with cancer were referred to this center. 4207 (50.6%) were female. The mean age of the men and women was 57.49 ± 19.08 and 52.16 ± 16.05 years, respectively. Most frequency (43.7%) was among men 60-80 years of age at the time of diagnosis and women (47.1%) 40-60 years of age. The most common cancer among women was breast cancer (41.4%) and among men was esophagus cancer (10.3%). Other common cancers were esophagus (8%), brain (6.3%), stomach (4.1%) and cervix (3.4%) in females and stomach (10.2%), brain (8.2%), prostate (6.9%) and lung (6.4%) in males.
CONCLUSION: The results showed that the most frequent cancers in men (60-80 years old) and in women (40-60 years old) are esophagus and breast cancer, respectively.

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ABSTRACT
BACKGROUND AND OBJECTIVE: Fukushima nuclear accident has produced concerns about radioactive distribution and subsequent exposure to ionizing radiation. The aim of the present study was the comparison between local gamma rays level before and after accident in Babol in north of Iran.
METHODS: In this cross sectional study, the environmental dosimetry was performed in 182 local health centers in Babol according to International Atomic Energy Agency standard protocol and the results were compared with similar previous survey in similar areas which was done at 2010 for determining of association between local external gamma rays and frequency of cancer in Babol, Iran.
FINDINGS: Results showed that there was no significant increase in local gamma ray level before (60.62±12.96 nSv/hr =0.53 mSv/y) and after (37.06±17.76 nSv/hr =0.33 mSv/y) accident in Babol in the areas under the study.
CONCLUSION: The results of this study showed that Fukushima nuclear accident has not significantly changed the local gamma rays level in Babol in northern Iran.

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ABSTRACT BACKGROUND AND OBJECTIVE: Nuclear medicine is one of the most important diagnostic modalities. The aim of present study was to estimate annual per capita effective dose in most common procedures performed in nuclear medicine centers in Iran in order to provide data for risk estimation due to exposure to ionizing radiation in nuclear medicine. METHODS: Corresponding data of patients underwent 5 main kinds of nuclear medicine exams in 10 major hospitals in Iran in six year period were used to estimate effective dose and also population dose due to exposure to ionizing radiation in nuclear medicine. FINDINGS: Based on the data of this study, the mean effective population dose per caput was 7.53 micro Sv per year. CONCLUSION: The mean effective population dose per caput per year is smaller than other countries and generally is similar to average background radiation in the world.

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ABSTRACT

Natural background radiation has been an interesting subject among scientific studies for many years. The effective radiation dose of human from natural sources is about 2.5 mSv/y but it is higher in some regions of the world. Ramsar in Mazandaran, Iran is one of the most important areas and it has the highest natural background radiation among whole residential areas of the world. Background radiation is an ionizing radiation in the environment that its source could be natural or man-made. Its natural sources are cosmic radiations, terrestrial radiation, internal radiation and radon and its man-made sources could be the nuclear power plants and the scatter radiations of atomic bomb tests. There are a lot of studies about the effects of natural background radiation on the biological systems and even humans. Most of these studies confirmed the harmless and even useful effects of the certain doses of natural background radiation. Also there are reports on the decrease, increase or even equality in risk of some cancers between low and high doses of radiation. Nevertheless extensive epidemiological studies are needed to confirm the effect of low dose radiation on carcinogenesis and other factors and even decrease or increase of the risk in different types of cancers is possible too.

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BACKGROUND AND OBJECTIVE: Radiation dose in oncology protocols is different for each patient according to the type and grade of the tumor, as well as adjuvant therapies. In the current treatment regimens, some predicting factors of individual radiosensitivity have not been considered. Individual radiotherapy can lower side effects through radiation dose reduction with respect to tumor control. In this study, the most determining factors for predicting radiosensitivity, used for individual radiotherapy, were reviewed.

METHODS: Data were retrieved through searching Sciencedirect, PubMed, Google scholar, Iranmedex and SID databases. The titles and abstracts of Persian and English articles were searched using keywords including: radiotherapy, the rate of cell proliferation, tumoral hypoxia, inherent radiosensitivity, tumor cell cycle, inhibitor factors of tumor, cancer stem cells, field dose radiation, apoptosis and predicting factors of radiosensitivity.

FINDINGS: Out of 90 articles, 25 original articles and reviews on predicting factors of the rate of radiosensitivity were thoroughly studied. Multiple factors, such as the presence of hypoxic zone and its size, inherent radiosensitivity and apoptosis, are crucial in determining individual radiation dose. Other factors, including previous history of exposure, blood type, left-or right-handedness and physical factors, should also be considered.

CONCLUSION: With respect to the physical, chemical, and biological parameters influencing individual radiosensitivity, radiotherapy individualization can promote tumor treatment and diminish side effects of radiotherapy on normal tissue.

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BACKGROUND AND OBJECTIVE: Filtration in radiology devices plays a pivotal role in weakening of soft X-ray photons and reduction of absorbed radiation dose by patients. This study aimed to evaluate the filtration rate of radiology devices at public hospitals affiliated to Babol University of Medical Sciences, Iran. 

METHODS: In this cross-sectional study, we used the DIAVOLT device to measure the level of radiology filtration. DIAVOLT was placed under the X-ray tube and exposed to radiation by applying multiple potential differences to the radiology device. After radiation, output potential differences were measured and recorded.

FINDINGS: This study was performed at Ayatollah Rohani, Shahid Beheshti and Yahyanejad hospitals located in Mazandaran, Iran. Potential differences of 50-80 kilo-volts (kV) were applied to radiology devices, and output voltage of the DIAVOLT device was observed to be compatible with input potential at the standard error rate of ±5. In Amirkola Children’s Hospital, level of filtration was 0.5 mm, while it was estimated at 2.5 aluminum mm in other hospitals. In addition, applied input time to the DIAVOLT device was compatible with output time. In Shahid Rajaee Hospital of Babolsar city, rate of input potential was higher than the output potential in the DIAVOLT device, which diverted from the standard level however, filtration degree was adequate.

CONCLUSION: According to the results of this study, kV examinations were accurate at all the hospitals affiliated to Babol University of Medical Sciences. Therefore, it could be concluded that rate of filtration is adequate in the radiology devices used in these health centers.

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