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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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Backgrounds: Bleomycin (BLM) has been labeled with radioisotopes and widely used in therapy and diagnosis. In this study BLM was labeled with [⁶²Zn] zinc chloride for oncologic PET studies.

Materials and methods: The complex was obtained at the pH=2 in normal saline at 90 ° C in 60 min. Radio-TLC showed an overall radiochemical yield of 95-97% (radiochemical purity > 97%). Stability of complex was checked in vitro in mice and human plasma/urine.

Results: Preliminary in vivo studies performed to determine complex stability and distribution of [⁶²Zn] BLM in normal and fibrosarcoma-bearing mice. [⁶²Zn] BLM accumulated significantly in induced fibrosarcoma tumors in mice according to bio-distribution/imaging studies.

Conclusion: [⁶²Zn] BLM can be used in PET oncology studies due to its suitable physico-chemical properties as a diagnostic complex in vitro and in vivo. Further studies should be performed for evaluation of the complex behavior in higher animals. Iran . J. Radiat. Res., 2003 1(1): 37 - 44.

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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 compositions of Ferrous sulphate, Agarose and Xylenol orange dye (FAX) and Ferrous sulphate, Gelatin and Xylenol orange dye (FGX) in solution of distilled water and sulphuric acid are two tissue-equivalent gel dosimeters. Ionizing radiation causes oxidation of Fe²⁺ ion to Fe³⁺ ions which diffuse through the gel matrix and blur the image of absorbed dose over a period of hours after irradiation.

Materials and methods: 25 mM sulphuric acid, 0.4 mM ferrous ammonium sulphate, 0.2 mM xylenol orange dye and 1% by weight agarose in distilled water named FAX and 0.1 mM ferrous ammonium sulphate, 0.1 mM xylenol orange dye, 50 mM sulphuric acid and 5% by weight gelatin in distilled water named FGX are used as two gel dosimeters. All chemicals were supplied by Sigma Aldridge Company, Germany . The gels were poured in Perspex casts and were irradiated to a beam of X ray from linear accelerators or x ray machine.

Results: In this study diffusion coefficients of FAX and FGX dosimeters have been measured through a computer program for different temperatures. The ferric ion diffusion coefficient (D) for the FAX and FGX dosimeters were measured as (1.19 ± 0.03) x 10^-2 cm².hr^-1 and (0.83 ± 0.03) x 10^-2 cm².hr^-1 respectively at room temperature.

Conclusion: For both dosimeters the diffusion coefficients decreased with gel storage temperatures down to 6^oC. FGX dosimeters have advantage of lower diffusion coefficient for a specified temperature. Iran . J. Radiat. Res. 2003 1(2): 79 – 86.

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Background: Acute radiation dermatitis is a very common side effect of radiation therapy in large numbers of cancers including breast cancer. Despite high prevalence rate of acute radiation dermatitis and also wet desquamation, a few trials on prophylaxis of this complication using topical treatment have been conducted. Despite effectiveness of topical corticosteroids in treatment of acute radiation dermatitis which are focused in the literature, yet there are some controversy about their usage in this regard. For this reason we attempted to investigate this subject via conducting a clinical trial.

Materials and Methods: This trial included 76 patients with pathologic diagnosis of breast cancer for whom radiotherapy has been planned. Patients were 27-70 years old. Patients with radical mastectomy received 5000 cGy within 5 weeks, and those with conservative surgery received 6000 cGy within 6 weeks divided in 200 centigray fractions. Patients were divided randomly into two groups, betamethasone and placebo, 38 patients in each group. In placebo group, 3 patients did not attend for weekly assessment. Additional one patient did not refer during follow-up period. Thus, they were excluded from the study. One group was given betamethasone 0.1% and other group was administered base of ointment as placebo.All patients consumed drug or placebo from the 1st day of treatment until one week after treatment completion as twice daily within tangential field. Patients were monitored for assessing dermatitis severity and its symptoms and also possible drug adverse effects one week after the therapy commenced and afterwards by one-week intervals as well as in an appointed day. Three weeks after termination of therapy, patients were also visited, and each examination provided information about dermatologic complications which were registered in the questionnaire.

Results: Mean times development of dermatitis in both betamethasone and placebo groups were 3.2500 and 2.2571 (weeks) respectively (t=-3.898 , p< 0.001). Maximal dermatitis intensity during treatment in betamethasone group was 3.5% 0, 86.8% I, 7.9% II, 0% III, 0% IV and in base of ointment receiving group were 0 %, 60% , 37.1%, 2.9% and 0% (P = 0.008), respectively. Maximum severity of complaints stated by patients in terms of burning and pruritus had been lesser in betamethasone group (P< 0.001). No significant differences were observed between two groups in terms of pain intensity.

Conclusion: Betamethasone valerate ointment is statistically significantly more effective than base of ointment alone in reducing acute radiation dermatitis. Iran . J. Radiat. Res. 2003, 1(2): 105 – 111.

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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: Ultrasound propagation velocity was measured experimentally in normal, fibroadenoma and ductal carcinoma breast tissues, in order to distinguish normal breast tissue from tumors.

Materials and methods: In quantitative measurements of ultrasound velocity, 403 breast tissue images were selected, comprising 130 normal breast tissue, 130 fibroadenoma, and 143 ductal carcinoma tumors. The cases were implanted in breast tissue mimicking materials and ultrasonic images (A-mode) at 35 ° C were processed and evaluated.

Results: It was observed that ultrasound propagation velocity is an important factor for distinguishing in vitro specimens of fibroadenoma and ductal carcinoma from normal tissue (P-value<0.005). Evaluation of ultrasound velocities showed that from normal breast tissue, fibroadenoma and ductal carcinoma, ultrasound velocity increases respectively. The discriminant functions of types of lesions, based on ultrasound velocity, have been formulated by discriminant analysis. The results indicate that probability of discrimination, sensitivity and specificity for tumors and normal breast tissues are 72, 60 and 100 percents at 35 ° C. With measuring ultrasound velocities, we can distinguish normal breast tissue of from ductal carcinoma and fibroadenoma masses (with the probability of 100%).

Conclusion: It is proposed that probably by measuring attenuation coefficient and ultrasound velocity on time, fibroadenoma and ductal carcinoma tumors can be differentiated well. Iran . J. Radiat. Res., 2003 1(3): 163 – 169

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Background: Medical x-rays are the largest man-made source of public exposure to ionizing radiation. It is important to avoid conditions where the amount of radiation used is more than that needed for the procedure.

Materials and Methods: The Entrance Skin Exposure (ESE) measurement was conducted for quality control of x-ray machines and survey of operator’s experimental techniques. The ESEs were measured by UNFORS dosimeter for five common types (12 projections) of x-ray procedures in standard man for the 18 public hospitals of Yazd province.

Results: The median, 3^rd quartile, minimum, and maximum values of each ESEs distributions are reported. The 12 histograms are presented showing wide distribution of measured ESE in each examination. The survey results are compared with guide levels that reported by CRCPD or NRPB. The sum of ESEs measurements such as in skull, Th-spine and L-spine are projection out of the guide levels. One of reasons of the wide ESEs distribution is miss unique role in selection of techniques for the same procedure and same patient size by operators in each center and even for one x-ray machine.

Conclusion: The findings support the importance of the on-going quality assurance program to ensure doses are kept to a level consistence with optimum imaging quality. Iran . J. Radiat. Res., 2004 1(4): 199-204

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Background: We designed an algorithmic model based on the logistic regression analysis and a non-algorithmic model based on the Artificial Neural Network (ANN).

Materials and methods: The ability of these models was compared together in clinical application to differentiate malignant from benign breast tumors in a study group of 161 patients' records. Each patient’s record consisted of 6 subjective features extracted from MRI appearance. These findings were encoded as features for an ANN as well as a logistic regression model (LRM) to predict biopsy outcome. After both models had been trained perfectly on samples (n=100), the validation samples (n=61) were presented to the trained network as well as the established LRMs. Finally, the diagnostic performance of models were compared to that of the radiologist in terms of sensitiv­ity, specificity and accuracy, using receiver operating characteristic curve (ROC) analysis.

Results: The average output of the ANN yielded a perfect sensitivity (98%) and high accuracy (90%) similar to that one of an expert radiologist (96% and 92%) while specificity was smaller than that (67% verses 80%). The output of the LRM using significant features showed improvement in specificity from 60% for the LRM using all features to 93% for the reduced logistic regression model, keeping the accuracy around 90%.

Conclusion: Results show that ANN and LRM prove the relationship between extracted morphological features and biopsy results. Using statistically significant variables reduced LRM outperformed of ANN with remarkable specificity while keeping high sensitivity is achieved. Iran . J. Radiat. Res., 2004 1(4): 217-228