Structural and thermoluminescence properties of lithium borate glass matrices under UV and beta radiation.

In the present work, glass samples in the (100 - x)B2O3-xLi2O binary system, with x varying from 30 to 50 mol%, were prepared using the conventional melting and moulding method, with the main objective of evaluating the thermoluminescence response when exposing these materials to ultraviolet (UV) radiation. Complementary analysis based on density, optical absorption on the UV-visible region (UV-vis absorbance), Fourier transform infrared spectroscopy on the medium region, X-ray diffraction, and differential thermal analysis measurements were performed. Thermoluminescence measurements of vitreous samples showed glow curves with at least one peak with a maximum temperature of ~170°C after exposure to UV radiation in the temperature range 50-250°C. Samples were also exposed to beta radiation in the temperature range 25-275°C, also showing single peaks with a maximum temperature of ~150°C.

Radiological Impact of Atmospheric Nuclear Weapons Tests at Mururoa and Fangataufa Atolls to Populations in Oceania, South America and Africa: Comparison with French Polynesia.

OBJECTIVE: To evaluate the potential radiological impact of atmospheric nuclear weapons tests conducted in 1966-1974 at Mururoa and Fangataufa atolls on populations in Oceania, South America and Africa. METHODS: Results of measurements of total beta(ß)-concentrations in filtered air and 131I activity concentrations in locally produced cow's milk in Oceania, South America and Africa after the tests were compared with those in French Polynesia. Radiation doses due to external irradiation and thyroid doses due to 131I intake with milk by local populations were also compared. RESULTS: Higher total ß-concentrations in filtered air, 131I activity concentrations in locally produced milk and radiation doses to local population were, in general, observed in French Polynesia than in other countries in the southern hemisphere. However, for specific years during the testing period, the radiological impact to South America was found to be similar or slightly higher than that to Tahiti. The resulting thyroid doses in the considered countries were lower than those in French Polynesia with two exceptions: thyroid doses due to 131I intake with cow's milk for 1-y old child in 1968 were higher in Peru (0.35 mGy) and in Madagascar (0.30 mGy) than in Tahiti (0.25 mGy). However, the populations outside French Polynesia received doses lower than those from the natural sources of radiation. CONCLUSION: According to the current knowledge in radiation epidemiology, it is very unlikely that nuclear fallout due to French nuclear tests had a measurable radiological and health impact outside French Polynesia.
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Princípios e aplicações da betaterapia em medicina veterinária / Principles and applications of beta therapy in veterinary medicine / Principios y aplicaciones de la terapia beta en medicina veterinaria

A betaterapia é uma forma de braquiterapia onde a fonte emissora de raios beta é posicionada diretamente na área em que se deseja tratar. As principais aplicações são em dermatologia e em oftalmologia no tratamento de lesões superficiais, pois as partículas betas têm grande poder de ionização e pequeno alcance no tecido. A radioterapia em medicina veterinária vem aumentando e apresentando resultados satisfatórios no Brasil e pelo mundo. Esta revisão teve como objetivo descrever os princípios e aplicações da betaterapia em medicina veterinária. Para a concretização foi realizada uma pesquisa bibliográfica, possibilitando assim, consolidar informações relativas à base teórica e ao tema proposto. Foi observado o uso do Estrôncio-90 (Sr90) nos principais procedimentos realizados em animais domésticos, selvagens e de experimentação, realçando a importância desta técnica adjuvante. A betaterapia mostrou-se exequível e de fácil manuseio para aplicações em medicina veterinária, especialmente nos casos de lesões e neoplasias superficiais. As fontes radioativas emissoras de partículas betas, como as de Sr90 não requerem grandes cuidados com proteção radiológica, o que contribui para a viabilidade da sua manipulação em radioterapia veterinária, principalmente nos procedimentos intra-operatórios.

Beta therapy is a form of brachytherapy where the beta ray emitting source is positioned directly in the area in which it is desired to be treated. The main applications are in dermatology and ophthalmology in the treatment of superficial lesions, since beta particles have great ionization power and small reach in the tissue. Radiotherapy in veterinary medicine has been increasing and presenting results satisfactory in Brazil and around the world. This review aimed to describe the principles and applications of beta-therapy in veterinary medicine. For the realization, a bibliographic research was carried through, making possible, to consolidate information related to the theoretical base and to the proposed theme. The use of Strontium-90 (Sr90) was observed in the main procedures performed on domestic, wild and experimental animals, highlighting the importance of this adjuvant technique. Beta therapy has been shown to be feasible and easy to handle for veterinary medicine applications, especially in cases of superficial lesions and neoplasms. Beta-emitting radioactive sources, such as those of Sr90, do not require great care with radiological protection, which contributes to the viability of their manipulation in veterinary radiotherapy, especially in intraoperative procedures.

La terapia beta es una forma de braquiterapia en la que la fuente emisora de rayos beta se coloca directamente en el área en la que se desea tratar. Las principales aplicaciones son en dermatología y oftalmología en el tratamiento de lesiones superficiales, porque las partículas beta tienen un gran poder de ionización y un alcance pequeño en el tejido. La radioterapia en medicina veterinaria ha ido aumentando y presentando resultados considerablemente en Brasil y en todo el mundo. Esta revisión tuvo como objetivo describir los principios y aplicaciones de la terapia beta en medicina veterinaria. Para la realización, se realizó una investigación bibliográfica que permitió consolidar información relacionada con la base teórica y el tema propuesto. El uso de Estroncio-90 (Sr90) se observó en los principales procedimientos realizados en animales domésticos, salvajes y experimentales, destacando la importancia de esta técnica adyuvante. Se ha demostrado que la terapia beta es factible y fácil de manejar para aplicaciones veterinarias, especialmente en casos de lesiones superficiales y neoplasias. Las fuentes radiactivas emisoras beta, como las de Sr90, no requieren un gran cuidado con la protección radiológica, lo que contribuye a la viabilidad de su manipulación en radioterapia veterinaria, especialmente en procedimientos intraoperatorios.

Princípios e aplicações da betaterapia em medicina veterinária / Principles and applications of beta therapy in veterinary medicine / Principios y aplicaciones de la terapia beta en medicina veterinaria

A betaterapia é uma forma de braquiterapia onde a fonte emissora de raios beta é posicionada diretamente na área em que se deseja tratar. As principais aplicações são em dermatologia e em oftalmologia no tratamento de lesões superficiais, pois as partículas betas têm grande poder de ionização e pequeno alcance no tecido. A radioterapia em medicina veterinária vem aumentando e apresentando resultados satisfatórios no Brasil e pelo mundo. Esta revisão teve como objetivo descrever os princípios e aplicações da betaterapia em medicina veterinária. Para a concretização foi realizada uma pesquisa bibliográfica, possibilitando assim, consolidar informações relativas à base teórica e ao tema proposto. Foi observado o uso do Estrôncio-90 (Sr90) nos principais procedimentos realizados em animais domésticos, selvagens e de experimentação, realçando a importância desta técnica adjuvante. A betaterapia mostrou-se exequível e de fácil manuseio para aplicações em medicina veterinária, especialmente nos casos de lesões e neoplasias superficiais. As fontes radioativas emissoras de partículas betas, como as de Sr90 não requerem grandes cuidados com proteção radiológica, o que contribui para a viabilidade da sua manipulação em radioterapia veterinária, principalmente nos procedimentos intra-operatórios.(AU)

Beta therapy is a form of brachytherapy where the beta ray emitting source is positioned directly in the area in which it is desired to be treated. The main applications are in dermatology and ophthalmology in the treatment of superficial lesions, since beta particles have great ionization power and small reach in the tissue. Radiotherapy in veterinary medicine has been increasing and presenting results satisfactory in Brazil and around the world. This review aimed to describe the principles and applications of beta-therapy in veterinary medicine. For the realization, a bibliographic research was carried through, making possible, to consolidate information related to the theoretical base and to the proposed theme. The use of Strontium-90 (Sr90) was observed in the main procedures performed on domestic, wild and experimental animals, highlighting the importance of this adjuvant technique. Beta therapy has been shown to be feasible and easy to handle for veterinary medicine applications, especially in cases of superficial lesions and neoplasms. Beta-emitting radioactive sources, such as those of Sr90, do not require great care with radiological protection, which contributes to the viability of their manipulation in veterinary radiotherapy, especially in intraoperative procedures.(AU)

La terapia beta es una forma de braquiterapia en la que la fuente emisora de rayos beta se coloca directamente en el área en la que se desea tratar. Las principales aplicaciones son en dermatología y oftalmología en el tratamiento de lesiones superficiales, porque las partículas beta tienen un gran poder de ionización y un alcance pequeño en el tejido. La radioterapia en medicina veterinaria ha ido aumentando y presentando resultados considerablemente en Brasil y en todo el mundo. Esta revisión tuvo como objetivo describir los principios y aplicaciones de la terapia beta en medicina veterinaria. Para la realización, se realizó una investigación bibliográfica que permitió consolidar información relacionada con la base teórica y el tema propuesto. El uso de Estroncio-90 (Sr90) se observó en los principales procedimientos realizados en animales domésticos, salvajes y experimentales, destacando la importancia de esta técnica adyuvante. Se ha demostrado que la terapia beta es factible y fácil de manejar para aplicaciones veterinarias, especialmente en casos de lesiones superficiales y neoplasias. Las fuentes radiactivas emisoras beta, como las de Sr90, no requieren un gran cuidado con la protección radiológica, lo que contribuye a la viabilidad de su manipulación en radioterapia veterinaria, especialmente en procedimientos intraoperatorios.(AU)

Theoretical and experimental characterization of emission and transmission spectra of Cerenkov radiation generated by 177Lu in tissue.

Cerenkov radiation (CR) is the emission of UV-vis light generated by the de-excitation of the molecules in the medium, after being polarized by an excited particle traveling faster than the speed of light. When ß particles travel through tissue with energies greater than 219 keV, CR occurs. Tissues possess a spectral optical window of 600 to 1100 nm. The CR within this range can be useful for quantitative preclinical studies using optical imaging and for the in-vivo evaluation of Lu177-radiopharmaceuticals (ß-particle emitters). The objective of our research was to determine the experimental emission light spectrum of Lu177-CR and evaluate its transmission properties in tissue as well as the feasibility to applying CR imaging in the preclinical studies of Lu177-radiopharmaceuticals. The theoretical and experimental characterizations of the emission and transmission spectra of Lu177-CR in tissue, in the vis-NIR region (350 to 900 nm), were performed using Monte Carlo simulation and UV-vis spectroscopy. Mice Lu177-CR images were acquired using a charge-coupled detector camera and were quantitatively analyzed. The results demonstrated good agreement between the theoretical and the experimental Lu177-CR emission spectra. Preclinical CR imaging demonstrated that the biokinetics of Lu177-radiopharmaceuticals in the main organs of mice can be acquired.

The ß- radio-guided surgery: Method to estimate the minimum injectable activity from ex-vivo test.

PURPOSE: Radio-guided surgery with ß- decays is a novel technique under investigation. One of the main advantages is its capability to detect small (⩽0.1 ml) samples after injecting the patient with low activity of radiopharmaceutical. This paper presents an experimental method to quantify this feature based on ex-vivo tests on specimens from meningioma patients. METHODS: Patients were enrolled on the basis of the standard uptake value (SUV) and the tumour-to-non-tumour activity ratio (TNR) resulted from 68Ga-DOTATOC PET exams. After injecting the patients with 93-167 MBq of 90Y-DOTATOC, 26 samples excised during surgery were analyzed with a ß- probe. The radioactivity expected on the neoplastic specimens was estimated according to the SUV found in the PET scan and the correlation with the measured counts was studied. The doses to surgeon and medical personnel were also evaluated. RESULTS: Even injecting as low as 1.4 MBq/kg of radiotracer, tumour residuals of 0.1 ml can be detected. A negligible dose to the medical personnel was confirmed. CONCLUSIONS: Radio-guided surgery with ß- decays is a feasible technique with a low radiation dose for both personnel and patient, in particular if the patient is injected with the minimum required activity. A correlation greater than 80% was observed between the measured counts and the expected activity for the lesion samples based on the individual SUV and the TNR. This makes identifiable the minimum injectable radiotracer activity for cases where 90Y is the utilized radionuclide.

Calibration of the 90Sr+90Y ophthalmic and dermatological applicators with an extrapolation ionization minichamber.

(90)Sr+(90)Y clinical applicators are used for brachytherapy in Brazilian clinics even though they are not manufactured anymore. Such sources must be calibrated periodically, and one of the calibration methods in use is ionometry with extrapolation ionization chambers. (90)Sr+(90)Y clinical applicators were calibrated using an extrapolation minichamber developed at the Calibration Laboratory at IPEN. The obtained results agree satisfactorily with the data provided in calibration certificates of the sources.

Feasibility of EBT Gafchromic films for comparison exercises among standard beta radiation fields.

The feasibility of using radiochromic films to verify the metrological coherence among standard beta radiation fields was evaluated. Exercises were done between two Brazilian metrology laboratories in beta fields from (90)Sr/(90)Y, (85)Kr and (147)Pm radiation sources. Results showed that the radiochromic film was useful for field mapping aiming uniformity and alignment verification and it was not reliable for absorbed dose measurements only for (147)Pm beta field.

Yttrium-90 -- current status, expected availability and applications of a high beta energy emitter.

Yttrium-90 ((90)Y, T(1/2) 64.14 h) is a key example of a high beta energy-emitting radionuclide which is available from the strontium-90 ((90)Sr)/(90)Y radionuclide generator system. Clinical uses of (90)Y-labeled radiopharmaceutical agents have been pursued for many years and many applications have proven to be clinical effective. These most notably include the application of 90Y-labeled antibodies for a variety of applications such as for effective treatment of non-Hodgkin's lymphoma. One of the major advantages for use of (90)Y is ready availability from the very long-lived (90)Sr parent (T(1/2) 28.78 y). Because of the importance of maintaining generator performance and minimizing parent breakthrough, this paper describes development, use and quality control of both high capacity cation adsorption-type and electrochemical generator systems. In addition, the preparation and targeting to tumors in mice of DOTA-conjugated Nimotuzamab (h-R3) antibody which recognizes the external domain of the EPFR antibody radiolabeled with (90)Y obtained from the electrochemical generator is also described. As a key example for clinical applications of (90)Y, the use of (90)Y-labeled biotin for intra-operative pre-targeting for radionuclide therapy (IART®) of breast cancer is also described.

Tratamento da úlcera escleral pós-cirurgia de pterígio e betaterapia por enxerto de esclera autóloga de espessura parcial / Partial thickness autologus scleral graft for treating scleral ulcers following pterygium excision and betatherapy

OBJETIVO: Avaliação dos resultados da utilização de enxerto de espessura parcial de esclera autóloga para o tratamento das úlceras esclerais profundas, como complicação tardia da exérese de pterígio associada à betaterapia. MÉTODOS: Foram tratados doze olhos de doze pacientes, nove femininos e três masculinos, com idade variando entre 48 e 82 anos, média 65,2 anos. RESULTADOS: Houve boa integração do enxerto em todos os casos, com resultado funcional e cosmético favorável e sem complicações. CONCLUSÃO: Várias técnicas de enxertia tem sido propostas para o tratamento da úlcera escleral: esclera e dura-máter homólogas, derme, cartilagem auricular e periósteo autólogos. No entanto, o procedimento com esclera autóloga apresenta reais vantagens em relaçâo aos enxertos empregados anteriormente. Não há referências na literatura quanto ao emprego de enxerto de esclera autóloga de espessura parcial para o tratamento da úlcera escleral.

OBJETICVE: The authors describes a surgical technique that utilizes autologus delaminated scleral graft for the management of deep scleral ulcers. METHODS: In this technique that were perfomed in 12 eyes of 12 patients, 9 female, 3 male, age from 48 to 82 years, mean age 65.2 years. RESULTS: Occurred good integration of the grafting in all cases without any complications. CONCLUSION: Many techniques have been proposed for the management of scleral ulcers: sclera and dura-mater, autologus derme, auricular cartilage and autologus periosteum.There is no reference in relation to autologus scleral grafting with partial thickness for the treatment of scleral ulcers, as proposed in this study.

Comparison of calibration results for an extrapolation chamber obtained with different 90Sr+90Y secondary standard sources.

Two secondary standard systems of beta radiation were used to calibrate a PTW extrapolation chamber Model 23391. Three (90)Sr+(90)Y sources of different activities were used in this calibration procedure. Medium-term stability of the response of the chamber was also studied. The calibration was performed with and without field-flattening filters. The relative standard deviation of the obtained calibration factors was 8.3% for the aluminum collecting electrode and 4.1% for the graphite collecting electrode.

Low or high fractionation dose ß-radiotherapy for pterygium? A randomized clinical trial.

PURPOSE: Postoperative adjuvant treatment using ß-radiotherapy (RT) is a proven technique for reducing the recurrence of pterygium. A randomized trial was conducted to determine whether a low fractionation dose of 2 Gy within 10 fractions would provide local control similar to that after a high fractionation dose of 5 Gy within 7 fractions for surgically resected pterygium. METHODS: A randomized trial was conducted in 200 patients (216 pterygia) between February 2006 and July 2007. Only patients with fresh pterygium resected using a bare sclera method and given RT within 3 days were included. Postoperative RT was delivered using a strontium-90 eye applicator. The pterygia were randomly treated using either 5 Gy within 7 fractions (Group 1) or 2 Gy within 10 fractions (Group 2). The local control rate was calculated from the date of surgery. RESULTS: Of the 216 pterygia included, 112 were allocated to Group 1 and 104 to Group 2. The 3-year local control rate for Groups 1 and 2 was 93.8% and 92.3%, respectively (p = .616). A statistically significant difference for cosmetic effect (p = .034), photophobia (p = .02), irritation (p = .001), and scleromalacia (p = .017) was noted in favor of Group 2. CONCLUSIONS: No better local control rate for postoperative pterygium was obtained using high-dose fractionation vs. low-dose fractionation. However, a low-dose fractionation schedule produced better cosmetic effects and resulted in fewer symptoms than high-dose fractionation. Moreover, pterygia can be safely treated in terms of local recurrence using RT schedules with a biologic effective dose of 24-52.5 Gy(10.).

Meta-analysis of beta radiation augmentation for trabeculectomy - results in distinct ethnic groups.

PURPOSE: To conduct a systematic review with meta-analysis on the efficacy of trabeculectomy (TREC) followed by beta irradiation (BRT/TREC) compared to TREC alone for glaucoma in terms of intraocular pressure (IOP) control and adverse effects of treatment in different ethnic groups. METHODS: A meta-analysis of randomized controlled trials (RCT) was performed comparing adjunct BRT treatment for glaucoma with standard TREC after 12 months. The MEDLINE, EMBASE, LILACS, and Cochrane Library databases, Trial registers, bibliographic databases and recent studies of relevant journals were searched. Two reviewers independently reviewed relevant reports and the references from these reports were searched for additional trials, using guidelines set by QUOROM statement criteria. RESULTS: Of a total of 1,350 citations, eight studies (five cohorts, three randomized) were identified and only 3 RCT were included in this meta-analysis. Higher IOP reductions were verified in the BRT arm compared to the control arm (mean difference=1.68 mmHg, 95% CI= 0.61-2.68, P=0.002). Uncontrolled postoperative IOP (>21 mmHg) was less frequent when BRT was used (BRT/ TREC arm) compared to the control arm (38/218=17.4% versus 9/239=3.8%; OR=6.7; 95% CI 3.2-14.3, P<0.0001). Although better IOP control was observed in all patients treated with adjuvant BRT, only Black patients displayed a significant difference (P=0.005). There were no significant differences between the BRT and control arms regarding loss of visual acuity, postoperative complications and necessity of cataract surgery. CONCLUSION: Adjunct BRT increases the success rate of TREC, with better results in non Caucasian patients, and does not influence the occurrence of postoperative complications.

Meta-analysis of beta radiation augmentation for trabeculectomy - results in distinct ethnic groups / Meta-análise da trabeculectomia potencializada pela radiação beta - resultados em grupos étnicos distintos

PURPOSE: To conduct a systematic review with meta-analysis on the efficacy of trabeculectomy (TREC) followed by beta irradiation (BRT/TREC) compared to TREC alone for glaucoma in terms of intraocular pressure (IOP) control and adverse effects of treatment in different ethnic groups. METHODS: A meta-analysis of randomized controlled trials (RCT) was performed comparing adjunct BRT treatment for glaucoma with standard TREC after 12 months. The MEDLINE, EMBASE, LILACS, and Cochrane Library databases, Trial registers, bibliographic databases and recent studies of relevant journals were searched. Two reviewers independently reviewed relevant reports and the references from these reports were searched for additional trials, using guidelines set by QUOROM statement criteria. RESULTS: Of a total of 1,350 citations, eight studies (five cohorts, three randomized) were identified and only 3 RCT were included in this meta-analysis. Higher IOP reductions were verified in the BRT arm compared to the control arm (mean difference=1.68 mmHg, 95 percent CI= 0.61-2.68, P=0.002). Uncontrolled postoperative IOP (>21 mmHg) was less frequent when BRT was used (BRT/ TREC arm) compared to the control arm (38/218=17.4 percent versus 9/239=3.8 percent; OR=6.7; 95 percent CI 3.2-14.3, P<0.0001). Although better IOP control was observed in all patients treated with adjuvant BRT, only Black patients displayed a significant difference (P=0.005). There were no significant differences between the BRT and control arms regarding loss of visual acuity, postoperative complications and necessity of cataract surgery. CONCLUSION: Adjunct BRT increases the success rate of TREC, with better results in non Caucasian patients, and does not influence the occurrence of postoperative complications.

OBJETIVO: Realizar uma revisão sistemática com meta-análise sobre a eficácia da trabeculectomia (TREC), seguida ou não por irradiação beta (BRT/TREC) para o tratamento do glaucoma, em termos de controle da pressão intraocular (PIO) e de efeitos adversos, em diferentes grupos étnicos. MÉTODOS: Uma meta-análise de ensaios clínicos randomizados (RCT) foi realizada, comparando os resultados de 12 meses da TREC com o uso adjuvante de BRT, com aqueles da TREC padrão. Foram fontes de pesquisa as bases de dados MEDLINE, EMBASE, LILACS, Cochrane, além de sítios de registro de ensaios clínicos, estudos recentes em revistas da área e outras bases de dados bibliográficos. Dois revisores avaliaram independentemente publicações relevantes e as referências desses trabalhos foram pesquisadas para procura de ensaios adicionais, de acordo com as diretrizes estabelecidas pelos critérios do QUOROM. RESULTADOS: De um total de 1.350 citações, oito estudos (cinco coortes e três aleatorizados) foram identificados e apenas 3 RCT foram incluídos nesta meta-análise. Maiores reduções na PIO foram verificadas no braço de estudo da BRT, comparado com o braço controle (diferença média=1,68 mmHg, 95 por cento CI= 0,61-2,68, P=0,002). A frequência de PIO pós-operatória não controlada (>21 mmHg) foi menor quando utilizada a BRT (BRT/TREC) em relação ao grupo controle (38/218 =17,4 por cento versus 9/239 =3,8 por cento; OR= 6,7 IC 95 por cento 3,2 14,3, P<0,0001). Apesar do melhor controle da PIO ter sido observada em todos os pacientes do braço BRT, apenas os pacientes negros apresentaram uma diferença significativa (P=0,005). Não houve diferenças significativas entre os braços BRT e controle, em termos de perda da acuidade visual, complicações pós-operatórias e necessidade de cirurgia de catarata. CONCLUSÃO: O uso de BRT adjuvante aumenta a taxa de sucesso da TREC, com melhores resultados em pacientes não-caucasianos, não influenciando a ocorrência de complicações pós-operatórias.

Natural radionuclides in major aquifer systems of the Paraná sedimentary basin, Brazil.

This paper describes the natural radioactivity of groundwater occurring in sedimentary (Bauru and Guarani) and fractured rock (Serra Geral) aquifer systems in the Paraná sedimentary basin, South America that is extensively used for drinking purposes, among others. The measurements of gross alpha and gross beta radioactivity as well the activity concentration of the natural dissolved radionuclides 4°K, ²³8U, ²³4U, ²²6Ra, ²²²Rn, ²¹°Po and ²¹°Pb were held in 80 tubular wells drilled in 21 municipalities located at São Paulo State and its border with Mato Grosso do Sul State in Brazil. Most of the gross alpha radioactivity data were below 1 mBq/L, whereas values exceeding the gross beta radioactivity detection limit of 30 mBq/L were found. The radioelement solubility in the studied systems varied according to the sequence radon>radium>other radionuclides and the higher porosity of sandstones relatively to basalts and diabases could justify the enhanced presence of dissolved radon in the porous aquifer. The implications of the data obtained in terms of standards established for defining the drinking water quality have also been discussed. The population-weighted average activity concentration for these radionuclides was compared to the guideline value of 0.1 mSv/yr for the total effective dose and discussed in terms of the choice of the dose conversion factors.

In vivo comparative study of hydroxyapatite labeled with different radioisotopes: evaluation of the scintigraphic images.

Radyosinovectomy (RSV) is a radiotherapeutic modality where a beta-emitting radionuclide is administered locally by intra-articular injection on the form of a colloid or radiolabeled particulate. RSV is a well-accepted therapeutic procedure in inflammatory joint diseases and has been successfully employed for more than 50 years as a viable alternative to surgical and chemical synovectomy. The aim of this work is to compare the in vivo stability of hydroxyapatite labelled with (177)Lu, (90)Y and (153)Sm. All radionuclides were labelled with high yield and were retained in the joint for 7 days, showing stability and usefulness as tools in the RSV treatment. A similar retention of the products in the muscle was observed when the particles were administrated in the muscle. However, the pure form of the radionuclides were rapidly cleared from the blood and accumulated in the liver when injected i.v.. Although (153)Sm-HA is already available for nuclear medicine procedures and clinical studies with (90)Y-HA have been developed, (177)Lu-labeled RSV agents will be economically more viable and has not been studied yet. Its favorable characteristics contribute to follow, to predict and asses the success of RSV by bone scintigraphy studies.

Mutagenesis of Aspergillus oryzae IPT-301 to improve the production of ¥â-fructofuranosidase

Aspergillus oryzae IPT-301, previously reported as a ¥â-fructofuranosidase producing microorganism, was successfully mutated using UV irradiation at 253.7 nm followed by the screening of survivors resistant to certain stress conditions. Strains were first subjected to the ¥â-fructofuranosidase activity assay using a portion from the colony grown in Petri dish as the enzyme source. Seven mutants with fructofuranosidase activity values relative to the parent culture between 140 -190 percent were selected from survivors grown at temperature of 40¨¬C or 0.018 percent (w/v) sodium dodecyl sulfate concentration. They were cultivated on a rotary shaker to characterize mycelium and extracellular fructosyltransferase activities. Three mutants named IPT-745, IPT-746 and IPT-748 showed the highest amount of mycelium activity whose values increased 1.5 -1.8 fold, compared with the parent strain. It was found that more than 55 percent of total enzyme activity (mycelium- plus extracellular- activity) from these strains was detected in the mycelium fraction. Only one mutant, IPT-747, exceeded the amount of extracellular enzyme exhibited by the parent strain (1.5 times). This mutant also showed the highest value of total fructosyltransferase activity.

Absorbed dose profiles for (32)P, (90)Y, (188)Re, (177)Lu, (153)Sm and (169)Er: radionuclides used in radiosynoviortheses treatment.

The main objective of this paper was to obtain the absorbed dose profiles for radionuclides of frequent or potential use in radiosynoviortheses. These profiles reveal the absorbed dose per activity of injected radionuclide (Gy/h*MBq) in the synovial membrane and the articular cartilage. The researched radionuclides were (32)P, (90)Y, (188)Re, (177)Lu, (153)Sm and (169)Er. The therapeutic range of each radionuclides in synovial tissue were also calculated. This range determines the synovial thickness that can be sufficiently irradiated and thus successfully treated. The S values for the synovial membrane and articular cartilage were calculated using as a model a cylinder with the source uniformly distributed in its volume. The synovial membrane was simulated varying the radius of the cylinder (from 0.5cm to 9cm) and its height (from 0.01cm to 0.04cm). The area in the base of the cylinder represents different sizes of the synovial surface (small, medium and large joints). The height of the cylinder represents different stages of the progression of the rheumatoid arthritis. The same model was used to simulate the articular cartilage but, the source was uniformly distributed into a cylindrical slab (0.01cm height and 1cm of radius. The results obtained allow the estimation of the dose that will be delivered to the synovial membrane and the articular cartilage for different joint sizes and different stages of progression of the rheumatoid arthritis (RA).

Effect of low-dose electron radiation on rat skin wound healing.

The aim of this study was to assess the effect of low-dose electron irradiation on morphological features of the wound healing process in rat skin. Surgical wounds were inflicted with a 2.3 x 1.4 cm template on 84 male rats that were assigned to 4 groups: IG1, immediately irradiated; IG2, irradiated 3 days after inflicting the wound; CG1 and CG2, control groups. Rats in IG1 and IG2 groups had their wounds exposed to 1 Gy of 6 MeV electron beam radiation, immediately after surgery and on the third postoperative day, respectively. Qualitative and histophotometric evaluations of tissue repair structures were carried out. Data were analyzed by ANOVA and Tukey's test (alpha = 0.05) and regression analysis. The repair process was delayed since the first sacrifice time in both irradiated groups, but in IG1, wound healing was closer to that of CG1; whereas in IG2, the delay was more pronounced. Based on the histological findings, it is possible to conclude that a low-dose of electron radiation delayed tissue repair in rat skin. The delay was longer in the skin irradiated 3 days after the beginning of tissue repair. However, the low-energy electron irradiation did not prevent wound healing.