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Background: A powerful and improved technique, Proton Induced X-ray Emission (PIXE) has been performed-yielding the elemental composition of 17 samples of surgically excised malignant and normal tumors of breast tissue. The samples without any further process as thick targets were put on capton foil backing. There are no homogenizing processes. The PIXE spectra analysis was performed using he non-linear least square fitting code AXIL and GUPIX.

Materials and Methods: The samples are taken from patients in the wide range of age and are bombarded by 2.0 Me v energy proton beams produced by van de graff accelerator in vacuum. The quantitative comparison between two types of tissues was evaluated by assessing the presence of c alcium, Potassium, Iron, Copper and Zinc, as minor and trace elements.

Results: Results in this study indicate that relative values of Cu / Zn, P / K and also Ca and S in benign type were higher than those in malignant type, but the concentration of Fe and Zn in cancerous tissues was significantly higher than those for benign type.

Conclusion: Results suggest significant elevation of Zinc in the pathological tissues. Cu/Zn ratio for both type of tissues are evaluated. The results show that this ratio in patients with breast cancer is significantly lower than the normal group. Selenium and Arsenic was not obtained in any of 17 samples. Most of the tissues of benign kind (Fibrocystic and Fibro adenoma) contain Cadmium. Calcium concentration in normal tissues is significantly higher than tumorous tissues. Iran . J. Radiat. Res., 2003 1(1): 23 - 27.

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Background: Previous investigations have revealed, cimetidine, a histamine H2-receptor antagonist, show radioprotective effects against gamma- and neutron-induced micronuclei in bone marrow erythrocytes. In this study, the anticlastogenic effects of famotidine and ranitidine, which act similar to cimetidine as histamine H2-receptor antagonists, was investigated.

Materials and Methods : Balb/c male mice were injected i.p. with various doses of famotidine and ranitidine two hours before 2 Gy gamma irradiation. Frequency of micronuclei was determined in bone marrow erythrocytes following each treatment.

Results: The results indicated that gamma irradiation alone can cause a high frequency of micronuclei formation and decrease cell proliferation ratio. Pre-irradiation injection of famotidine and ranitidine, of various doses, effectively reduced the number of micronucleated polychromatic erythrocytes (MnPCEs), yet has no effect on cell proliferation ratio (PCEs/PCEs+NCEs). In fact, these two drugs reduce the clastogenic effects of gamma rays, while they are ineffective against the cytotoxic properties of gamma rays.

Conclusion: The dose reduction factor (DRF) calculated, shows a DRF=2 for famotidine and a DRF=1.8 for ranitidine which is indicative of a high radioprotective property of these drugs. The mechanism in which these drugs reduce clastogenic effect of gamma radiation is not fully understood. It might be due to their antioxidant and free radical-scavenging properties. Iran . J. Radiat. Res. 2003 1(1): 29 - 35.

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Background : There are growing evidences for chromosomal radioadaptive response in human lymphocytes . Highly variable inter- and intra-individual responses have been reported. Some individuals are non-responders and even in some donors the frequency of chromatid aberrations induced by a challenge dose increases by pre-exposure to an adapting dose. It has been proposed that the lack of radioadaptive response is due to transient physiological factors.

Materials and Methods : We found a young healthy donor who exhibited no radioadaptive response in our initial experiments. After a common adapting dose, the donor occasionally showed a highly increased susceptibility to subsequent high-dose irradiation. To assess whether the lack of radioadaptive response and the induction of a synergistic effect are transient responses , we have performed a 3-year follow-up study employing micronuclei in binucleated cells besides chromatid aberrations as biological endpoints. To eliminate the effect of the cell cycle on intrinsic radiosensitivity of a cell, we used the multiple-fixation regimen for analysis of chromosomal aberrations.

Results : This donor showed no adaptive response in any experiment.

Conclusion : Considering the consistent non-responsiveness observed throughout our serial experiments, it may be concluded that the lack of radioadaptive response is not attributed to some transient physiological factors but rather to permanent constitutional traits. Iran. J. Radiat. Res., 2003 1(1): 55 - 61.

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Background: The method of proton induced X-ray emission (PIXE) has been widely used as a sensitive technique to trace elemental analysis in both biological and medical fields. The sensitivity of this powerful method is in the order of ppm .The aim of this work is to analyze structural composition of 4 heavy trace elements with Z greater than 24 (Mn, Fe, Cu, Zn) in two kinds of gallstones and to compare the results for various ages of patients by PIXE quantitatively.

Materials and methods: The pigment and cholesterole gallstones were obtained from 12 patients during surgical operations and were used for in vitro study. The age of the patients were between 22 and 78 years. Both cholesterol and pigmented types were analyzed for shell and center. The samples were bombarded using a 3.0 MeV van-de-Graff accelerator at nuclear research center of Atomic Energy Organization of Iran for the PIXE measurement.

Results: In pigment gallstones, the mean value of Mn, Fe, and Zn in shell is greater than in the center and Cu in the shell is smaller than center. In cholesterol gallstones, neither in the shell nor in center, Zn was not observed. The composition of Mn and Fe in center is greater than in shell. In the patients older than 40 years, the concentration of heavy trace elements increases, and those in cholesterol stones are nearly two times larger than in pigment stones.

Conclusion: Comparison of two types of gallstones shows that the center of the pigment stones is very similar to cholesterol type .It is concluded that the origination of gallstone in human is common but formation and growth are different. Iran . J. Radiat. Res. 2003 1(2): 93 – 97.

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Background: Mannitol is present in the Ethyol ^® (the trade name of amifostine) as an excipient. The mechanism of radioprotection of amifostine is radical scavenging. Since mannitol is another known radical scavenger, we studied the probable additive or synergistic effect of mannitol on the effect of amifostine.

Material and Methods: Mice were irradiated with Co-60 γ -ray in the presence 400mg/kg mannitol alone or in combination with 400mg/kg amifostine. Survival of mice was assessed within 30 days after irradiation (LD 50/30). Moreover, the protective effect of drugs was evaluated using micronuclei (MN) assay. Slides were prepared using femoral bone marrow flush and stained in May-Giemsa. The frequency of MN was determined in polychromatic erythrocytes (PCE) for each sample.

Results: Similar LD50/30 was observed for irradiated mice in the presence of amifostine alone or in combinations with mannitol. High frequency of MN was produced by 3 Gy γ -rays. Amifostine reduced radiation induced MN dramatically, but mannitol had no effect on γ -rays induced MN. Combination of mannitol with amifostine did not change the effect of amifostine alone.

Conclusion: Radioprotection of ethyol is due to the effect of amifostine. Presence of mannitol apparently has no role in radioprotective effect of amifostine. Iran . J. Radiat. Res., 2003 1(3): 151 - 155

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Background: Premature chromosome condensation (PCC) is a method for interphase chromosome analysis in biodosimetry. This study was performed to verify the usefulness of PCC induced by calyculin A in human peripheral blood lymphocytes (pbl) for biological dosimetry and possible construction of dose-response curve.

Materials and Methods: Peripheral blood was obtained from a healthy donor and exposed to various doses (0.25–4 Gy) of γ -rays. The frequency of simple breaks and dicentrics were scored in G2/M chromosomes of Giemsa stained cells.

Results: Results show that the frequency of simple chromosome breaks appears to increase linearly with dose while the frequency of dicentrics apparently increases linear-quadratically with the dose.

Conclusion: Induction of chromosome condensation by calyculin A is a powerful biodisimetric method, which provides a high number of spreads for analysis. With the use of this method, it is possible to overcome problems related to low mitotic index or cell-cycle alterations in routine metaphase analysis and low fusion rate in conventional PCC technique. Iran . J. Radiat. Res., 2004 2 (1): 15-20

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Background: Induction of radioadaptive responses in cells pretreated with a low dose radiation before exposure to a high dose is well documented by many investigators. The aim of this study is to determine the frequency of chromosomal aberration in peripheral blood lymphocytes of patients treated by radioiodine (¹³¹I) for hyperthyroidism, with or without previous thyroid scan with ^99mTc.

Materials and Methods: Venous blood samples were obtained from 35 patients one month after radioiodine therapy and cytogenetically evaluated using analysis of metaphase in two groups. The first group (n = 15, 13 females and 2 males, mean age= 44.7 ±11.5 years and mean weight 74.4±7.9 Kg) received 5 mCi ^99mTc for thyroid scanning 38.6±19.9 days before radioiodine therapy with 10.4 ± 3.4 mCi ¹³¹I. The second group (n = 20, 14 females and 6 males, mean age = 41.0 ± 10.8 years and mean weight = 68.1±9.2 Kg) didn't have history of thyroid scanning. We also studied a control group (n = 29, 11 Females and 8 males, mean age = 33.7±7.4 and mean weight = 70.0±8.8 Kg) who didn't have any history of diagnostic or therapeutic and also occupational exposure.

Results: The mean frequency of total chromosomal aberrations in the first and second groups and controls were 1.46 ±1.55, 1.65 ± 1.62 and 0.93 ± 0.92 respectively. Results also showed that the mean frequency of total chromosome aberration in two groups were higher than controls and significantly higher in patients who had not received ^99mTc compared those who had undertaken thyroid scan before radioiodine therapy (p=0.03).

Conclusion: These findings may indicate the fact that the radiation dose received from ^99mTc could induce resistance to subsequent higher radiation dose of ¹³¹I in peripheral blood lymphocytes and it might be due to cytogenetic radioadaptive response. Iran . J. Radiat. Res., 2004 2 (2): 69-7 4

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Background: Lymphocyte-dicentric assay is the most generally accepted method for biological dosimetry of overexposed individuals. In this study, the frequency of unstable chromosome
aberration in blood lymphocytes was used to estimate radiation dose received by individuals. Evaluation of dose using a calibration curve produced elsewhere may have a significant uncertainty therefore, experiments were performed to produce a dose-response curve using an
established protocol of international atomic energy agency.

Materials and Methods: Lymphocytes in whole peripheral blood obtained from healthy
individuals, were exposed to various doses of gamma radiation (0.25 – 4 Gy). Then after 1 hour of incubation in 37 ^oC, were cultured in complete RPMI-1640 medium. 500 mitoses were
analysed for the presence or absence of unstable chromosomal aberrations for each radiation dose after the standard metaphase preparation and staining slides.

Results and Conclusion: Intercellular distribution of dicentric chromosomes at each radiation dose has been used to contrast a dose-response curve. It seems that dose-effect relationship
follows with the linear-quadratic model. There is a good agreement between our dose-response curves with similar published studies by other laboratories. Iran . J. Radiat. Res., 2004 2 (2): 85-8 8

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Background: Intraoral radiographies are the most frequent X-ray examinations in humans.
According to International Commission on Radiation Protection (ICRP) recommendations, the selection of a diagnostic reference level (DRL) should be specific to a country or region. Critica l organs such as thyroid gland are exposed to X-rays in intraoral radiography and these exposures should be kept as low as reasonably achievable. To assist the development of DRLs for intraoral radiography, a National Radiation Protection Department-sponsored pilot study was carried out.

Materials and Methods: Thermoluminescent dosimetry (TLD) is widely acknowledged to be the recommended method for measuring entrance surface doses (ESD). In this study, ESD was measured using LiF thermoluminescent dosimeters (TLD-100) on the skin (either mandibular or maxillary arcs) of 40 patients. Three TLD chips were placed on the skin of each patient. The doses were averaged for each radiography and mean ESD of all patients calculated.

Results: The mean ± SD entrance surface dose at the center of the beam on the patients' skin in intraoral radiography was 1.173 ± 0.606 mGy (ranged from 0.01 to 0.40 mGy). The mean ESD for male and female patients were 1.380 ± 0.823, and 1.004 ± 0.258 respectively. No statistically significant difference was found between these means. Despite its necessity, in national level, there is no published data on the diagnostic reference levels for intraoral radiography. However, the results obtained in this study are lower than those reported by investigators in other countries.

Conclusion: In IR Iran, due to lack of large scale studies, no diagnostic reference levels have been set for X-ray diagnostic procedures. Due to lack of national diagnostic reference levels, it is not possible to clarify whether in intraoral radiographies any dose reduction techniques are needed. We intend to perform similar nationwide studies to set the diagnostic reference level for intraoral radiography. Iran . J. Radiat. Res., 2004 2 (3): 127-133

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Being on the right path

The 1^st issue of the Iranian Journal of Radiation Research (IJRR) was published two years ago (June 2003). This journal was initiated to bring together the various disciplines of radiation oncology, radiation biology, medical physics, nuclear medicine and other related subjects to intensify the dialogue between basic and clinical researchers especially those working in Iran. Within the last two years, this journal has tried to offer an ideal platform for the exchange of detailed scientific information concerning the latest developments in the field of radiation research, from various institutes, hospitals or even individuals. IJRR has been one of the specialized journals when published 2 years ago. The executive committee of the journal has been anxious about the quality and quantity of papers received by the IJRR office. The reason is that, the research activities in these fields are unexplored. Then, we believed that there might not be sufficient numbers of articles to be published in a specialized magazine as IJRR. Now, only a little over 2 years we have realized potential peoples and centers working in this area, not only in Iran but in other countries who contributed sincerely to the journal so that we are not worried about the materials to be published. We have realized that the existence of such a unique journal is a must both for Iran and the researchers in the region.
    Shortly after publishing the 1st issue, we tried to computerize all activities in the editorial office, including online review by our reviewers. The journal’s website is one of the most complete websites among Iranian journals with search capabilities and free access to abstracts and full PDF texts by readers and our visitors.
   The scientific quality of the journal specifically depends on the quality of papers submitted and the keen attention of the journal’s reviewers. These efforts were led to recognition of the journal as a scientific and academic research source by the ministry of Health and Medical Education. It has also been indexed by Index Medicus for Eastern Mediterranean Region (IMEMR). And now, in an annual qualification of scientific medical journals, IJRR is ranked among the highest scored journals.
.    We are proud to publish the 3rd volume of the journal with a short delay. To fulfill the interest of our readers and taking another step toward being internationally published in the field of radiation research, we have made some changes in the structural appearance and reference citation according to Vancouver’s format.
     We would like to express our special thanks to our editorial board for their help and suggestions, all reviewers for their sincere help and careful review of the articles and my colleagues at the editorial and publishing office.  I doubt we could publish this journal without their interest and efforts. IJRR is looking forward to receiving the invaluable papers from Iranian and foreigner scientists to be published in the forthcoming issues.