[en] Cytogenetic findings in 18 cases of suspected overexposure to ionizing radiations are shown. Despite the fact that in almost every case a number of aberrations was described, it was possible the estimation of biological doses in only two of them. Six persons (students working with x-rays in a practice) received very localized high doses in fingers and eyes because of the incredibly erroneous use of an x-ray diffraction machine, being their biological doses to whole body not relevant at all. Typical radiation-induced chromosomal damage (which is useful for biological dosimetry) is the appearance of dicentric chromosomes, chromosomal rings and acentric fragments, bu the greatest amount of of cytogenetic abnormalities found in this group are chromosomal breaks and gaps, chromatid aberrations, translocations, deletions and radical figures. This led us to suppose a high number of background chromosomal aberrations in this people, probably because[of wrong application of radiation protection rules. (authors). 7 refs., 1 tab

[en] As part of the second intercomparison run of ARCAL-IV, it was analyzed the marine sediment, reference materials PACS-NR CC1 by INAA, in the RP-10 Reactor with a thermal flux of 7,8 x 10¹³ n/cm² s. The results obtained (± 1σ,n=4) were: Co: 17,2±0,8 ppm; Cr:97,8±0,6 ppm; Fe: 46,0± 0,7 ppm; Na: 31,0±1,09/kg; Sb: 175±5 ppm; in good agreement with the certified values. The results in ppm (±18,n=4), for non certified elements were:Ba: 730±58; Ce: 25±3; Cs: 3,8±0,8; Eu: 1,00±0,03; Hf: 3,30±0,07; Lu:0,25±0,04; Rb: 44,0±0,9; Sc: 14,40±0,04; Sm: 3,4±0,5; Ta: 0,60±0,03; Tb: 0,5±0,05; Th: 3,80±0,02; U: 2,6±0,4; which are in good agreement with other three Latin American and one European INAA Laboratories. It was used the comparative method with AGV-1, GSP-1 and G-2 , USGS reference materials, as standards. (authors). 7 refs., 4 tabs

[en] The facility of neutron radiography at the RP-10 peruvian research reactor is described. The factor of collimation L/D is 149; the Cadmium ratio for the gold in the inspection's area is 4.5, and the thermal neutrons flux on the sample is 3,14 x 10⁶ n/cm² s (author). 5 refs. 5 fig

[en] In order to establish the nature of certain features found on bone scans, ten cases, which had not been submitted to prior thoracic surgery and which showed costal involvement on bone scan, were selected among all cases referred to the Nuclear Medicine Center between 1987 and 1992. Gamma graphic findings included diffuse costal hyper concentration in five cases (three of which showed costal lysis on X-ray films), and segmental hyper concentration in the order five (which provided negative findings on X-ray). In all cases, such hyper concentration occurred contiguous to the tumoral mass. The neoplastic nature of costal involvement was confirmed through biopsy and/or clinical and/or radiological evolution. (Authors). 11 refs., 2 ills

[en] PARET code was used to simulate accidental situations arising from positive reactivity insertions, in order to analyze the behavior of RP-10 reactor. The simulations considered three different cases: First is for the reactor operating at 10 Mw nominal power with 3 pumps in use, the second, at 6.6 Mw with only one pump working. In all cases the reactor trip was assumed when a 12 Mw power level is reached. An additional simulation for the reactor operating at 50w before the reactivity insertion, showed to be the worst accidental situation of all cases because of the higher temperature and power rise. Hot channel thermohydraulic and kinetic parameters have been evaluated at each axial mesh point and transient time step. None of the cases showed melting of fuel plates

[en] It has been made a synthesis of 1-hydroxyethyliden 1,1 Disodium phosphonate product and then its labelling with 99m Tc. Diphosphonate synthesis was made according to albright and Wilson's patent (1966). It was divided into two stage: the first one to prepare the diphosphonic acid and the disodic salt was obtained by titration in the second stage. Hydroxy ethyliden disodium phsphonate identification was made by NMR spectroscopy. Afterwards, it was made its labelling by reducing sodium pertechnetate 99m Tc with tin chlorides. In this way, It was established the formulation for 99m Tc-Sn hydroxyethyliden disodium phosphonate product (99m Tc-HEDSP). It has been prepared 99m Tc-HEDSP reagent set which adjust every required-specification to be used in osseous gamma graphy in human beings, from which is obtained a labelled product with a good chemical stability and radiochemical purity higher than 95

[en] Short communication

[en] CA 15-3 is a tumor marker useful in evolution control of breast cancer, being the serum levels trend the most important parameter. The purpose of this study was to report our experience and show the concordance of bone scan and CA 15-3 in patients with breast cancer attending the Breast and Bone Department of INEN from June to December 1993. One hundred patients had serum CA 15-3 quantification between June and December of 1993 in Nuclear Medicine Center (Peruvian Institute of Nuclear Energy and National Institute of Neoplasic Diseases). We selected 52 patients which simultaneously had a bone scan performed. Patients age ranged from 21 to 67 years (media of 44,57 years). ^99mTc methylenediphosphonate produced by IPEN was the radiopharmaceutical employed. A GE AZS-400 gamma camera was utilized to obtain the bone scans. Ca 15-5 quantification was performed with ELSA-CA 15-3 (CIS bio France) IRMA kit. Bone scan and CA 15-3 media of 17,06 U/ml (DS 15,4). Eight patients had a positive bone scan with a CA 15-3 media of 41,6 U/ml (SD 23,0). CA 15-3 levels ranged between 4,6 and 96,0 U/ml in the first group and 10,1 U/ml to 75,0 U/ml in the second group. Using a cut-off point of 30 U/ml the sensitivity of CA 15-3 was 62,5% and the specificity 93,2% respectively. Mean CA 15-3 values of the negative and positive bone scan groups were significantly different (p=0,0361). The high negative predictive value of CA 15-3 may help to establish which patients will benefit from bone scan procedure. (authors) 42 refs., 2 tabs

[en] The (La_1-xGd_x)_1,85Sr_0,15CuO₄ (0,0≤ x ≤ 1,0) system doped with ⁵⁷Fe (1 at %) was studied by ⁵⁷Fe mossbauer spectroscopy, AC susceptibility and x-ray diffraction. An interpretation of the different sites of Fe(Cu) as a function of the neighboring oxygen and the characteristics of the phases T (x=0), T^* (x=0,45) and T^'(x=1), was obtained at room temperature. The 4,2 K spectra show that the magnetic ordering of the Fe(Cu) is influenced by the oxygen local geometry. Mossbauer measurements at high temperature were performed in situ on a Gd_1,85Sr_0,15CuO₄ sample (T^' phase) at reduced pressure. A Debye temperature of about 328 K was obtained and the analysis of the variation of relative intensities of the various subspectra allowed to monitor the oxygen desorption near the Fe ions

[en] In this work the preparation of nanoparticles of magnetite by methods of precipitation in inverse microemulsions and the conventional method 'Chemical Co-precipitation' is reported. Magnetite nanoparticles were characterized by X-ray diffraction, Moessbauer spectroscopy and vibrating sample magnetometer (VSM). The results showed that the nanoparticles obtained by the method of precipitation in inverse microemulsion showed a superparamagnetic behavior and had a particle average diameter of 9 nm, while by the conventional method 'Chemical Co-precipitation' were 17 nm. In addition, other benefits observed in the application of the method of precipitation in inverse microemulsion with regard to the conventional method is that it allowed obtaining spheroidal magnetite nanoparticles, monodisperse and with magnetic and chemical properties which might have better results in medical applications. (author)