Radioimmunotheranostic Pair Based on the Anti-HER2 Monoclonal Antibody: Influence of Chelating Agents and Radionuclides on Biological Properties.

The oncogene HER2 is an important molecular target in oncology because it is associated with aggressive disease and the worst prognosis. The development of non-invasive imaging techniques and target therapies using monoclonal antibodies is a rapidly developing field. Thus, this work proposes the study of the radioimmunotheranostic pair, [111In]In-DTPA-trastuzumab and [177Lu]Lu-DOTA-trastuzumab, evaluating the influence of the chelating agents and radionuclides on the biological properties of the radioimmunoconjugates (RICs). The trastuzumab was immunoconjugated with the chelators DTPA and DOTA and radiolabeled with [111In]InCl3 and [177Lu]LuCl3, respectively. The stability of the RICs was evaluated in serum, and the immunoreactive and internalization fractions were determined in SK-BR-3 breast cancer cells. The in vivo pharmacokinetics and dosimetry quantification and the ex vivo biodistribution were performed in normal and SK-BR-3 tumor-bearing mice. The data showed that there was no influence of the chelating agents and radionuclides on the immunoreactive and internalization fractions of RICs. In contrast, they influenced the stability of RICs in serum, as well as the pharmacokinetics, dosimetry and biodistribution profiles. Therefore, the results showed that the nature of the chelating agent and radionuclide could influence the biological properties of the radioimmunotheranostic pair.

Estudio comparativo de la diversidad de las características clínicas dentales en poblaciones militares de Portugal y España / Diversity in dental clinical characteristics in Portuguese and Spanish military populations

Introducción: Se ha realizado una comparación de las características dentales de 2poblaciones militares de Portugal y España. El objetivo principal de esta investigación fue identificar aquellas características dentales que podrían ser de utilidad para diferenciar estas poblaciones en un análisis forense. Material y métodos: El estudio se realizó en una muestra compuesta por 5.136 militares profesionales de las fuerzas armadas, el 31,9% eran militares portugueses y el 68,1% del total de la muestra pertenecían a las fuerzas armadas españolas. Los datos dentales se registraron empleando los símbolos dentales descritos en Forensic Dental Symbols(R), gestionados con la base de datos Dental Encoder(R). Resultados: La población de estudio estaba constituida por un 86,6% de hombres (88,1% en la muestra española y 83,4% en la muestra portuguesa) y un 13,4% de mujeres (11,9% en la muestra española y 16,6% en la muestra portuguesa). La frecuencia de dientes no restaurados fue menor para los primeros molares en todos los cuadrantes, mientras que la mayor frecuencia de esta característica (>90%) se observó en los dientes anteriores, superiores e inferiores, y en los primeros premolares inferiores. Las frecuencias más altas de tratamientos restauradores fueron encontradas para los primeros y segundos molares en todos los cuadrantes, y las mayores frecuencias de ausencias dentarias se observaron en los terceros molares (superior al 28% en todos los cuadrantes). El análisis de concordancia mostró que las correlaciones entre los dientes contralaterales fueron significativamente mayores que entre los dientes antagonistas, para ambas muestras poblacionales de estudio. Conclusiones: Nuestros resultados proporcionan información potencialmente útil sobre la importancia de las bases de datos de registros dentales y el análisis de las características dentales con fines de identificación

Introduction: Dental characteristics were compared in population samples of Spanish and Portuguese military personnel. The main aim of this study was to identify those dental characteristics that could potentially serve to differentiate between these populations in a forensic analysis. Material and methods: A sample of 5136 individuals belonging to the professional military staff of the Portuguese and Spanish armed forces was studied. Dental data were recorded with the Forensic Dental Symbols(R) for the Dental Encoder(R) database. The population sample analysed in this study consisted of 68.1% Spanish and 31.9% Portuguese individuals. Results: The population was mostly male, with 86.6% men (88.1% in the Spanish sample versus 83.4% in the Portuguese sample), and 13.4% women (11.9% Spanish and 16.6% Portuguese). The frequency of unrestored teeth was lowest for first molars in all quadrants, and the highest frequency of unrestored teeth (>90%) was for the upper and lower anterior teeth and lower first premolars. The highest frequencies of restorative treatment were found for the first and second molars in all quadrants, and the highest frequencies of missing teeth were found for the third molars (always >28%). Concordance analysis showed that correlations between contralateral teeth were significantly higher than between antagonist teeth in both samples. Conclusions: Our findings provide potentially useful information on the importance of dental record databases and their value for identification purposes

Forensic Medicine and the Military Population: International Dental Records and Personal Identification Concerns.

INTRODUCTION: The first goal of this research was to perceive the global commitment towards the organization and archiving of dental records and to compare it with each country's security risk rating. The second one was to study dental records in a sample of the Portuguese military population, using the available national dental records. MATERIAL AND METHODS: An e-mail was sent to representative dentistry associations in several countries, requesting some information concerning the professionals' awareness of this issue. After obtaining permission from the Ethics Committee, the information was collected through the Forensic Dental Symbols® system into the Dental Encoder®, as an extension of a Spanish study, and a generic codification was used (unrestored, restored, missing and crowned teeth). RESULTS: The most common dental record retention period is ten years after treatment. Observing the samples' dental records (595 files), we found a total of 19 040 analyzed teeth, with the following frequencies: unrestored (89.6%), restored (7.0%), missing (2.2%) and crowned (1.1%). DISCUSSION: There is a wide range of guidelines on how long dentists should keep dental records. Especially for the military population, dental records must include detailed information concerning each tooth situation, in order to support the process of human identification. CONCLUSION: This article reinforces the need for mandatory quality dental records in all countries, which must be efficiently stored and easily accessible in case dental identification is necessary. For the military population, these requirements are especially important, due to the added risks to which this group is subject.

Introdução: Esta investigação teve o intuito de procurar conhecer o comprometimento global relativamente à organização e arquivo dos registos dentários e compará-lo com o risco de segurança de cada país. Por outro lado, procurou-se estudar os processos clínicos de uma amostra da população militar Portuguesa, utilizando-se para o efeito os registos dentários. Material e Métodos: Foi enviado um e-mail para associações dentárias e solicitada informação sobre o tempo de guarda dos registos dentários. Após autorização prévia da Comissão de Ética, a informação foi recolhida através do sistema Forensic Dental Symbols® para Dental Encoder®, como uma extensão de uma investigação realizada em Espanha e utilizada a codificação genérica (dentes sãos, com restaurações, ausentes e coroas). Resultados: Globalmente, dez anos após o último tratamento, foi o procedimento mais comum relativamente ao tempo de guarda dos documentos. Após observação dos registos dentários da amostra (595 militares) verificou-se um total de 19 040 dentes analisados, com as seguintes frequências: dentes sãos (89,6%), com restauração (7,0%), ausentes (2,2%) e coroas (1,1%). Discussão: Existe grande variedade de orientações sobre quanto tempo têm que ser guardados pelos profissionais de saúde os seus registos. Nos registos dentários da população militar deve-se incluir informação detalhada de cada dente, de maneira a suportar o processo de identificação humana. Conclusão: Este artigo reforça a necessidade de registos dentários de qualidade em todos os países, com manutenção eficiente para a identificação humana. Na população militar torna-se especialmente importante, devido ao facto de este ser um grupo sujeito a riscos acrescidos.

Cytogenetic and dosimetric effects of (131)I in patients with differentiated thyroid carcinoma: comparison between stimulation with rhTSH and thyroid hormone withdrawal treatments.

A study directed to the cytogenetic and dosimetric aspects of radionuclides of medical interest is very valuable, both for an accurate evaluation of the dose received by the patients, and consequently of the genetic damage, and for the optimization of therapeutic strategies. Cytogenetic and dosimetric effects of (131)I in lymphocytes of thyroidectomized differentiated thyroid cancer (DTC) patients were evaluated through chromosome aberration (CA) technique: Euthyroid patients submitted to recombinant human thyroid-stimulating hormone (rhTSH) therapy (group A) were compared with hypothyroid patients left without levothyroxine treatment (group B). CA analysis was carried out prior to and 24 h, 1 week, 1 month and 1 year after radioiodine administration (4995-7030 MBq) in both groups. An activity-response curve of (131)I (0.074-0.740 MBq/mL) was elaborated, comparing dicentric chromosomes in vivo and in vitro in order to estimate the absorbed dose through Monte Carlo simulations. In general, radioiodine therapy induced a higher total CA rate in hypothyroid patients as compared to euthyroid patients. The frequencies of dicentrics obtained in DTC patients 24 h after treatment were equivalent to those induced in vitro (0.2903 ± 0.1005 MBq/mL in group A and 0.2391 ± 0.1019 MBq/mL in group B), corresponding to absorbed doses of 0.65 ± 0.23 Gy and 0.53 ± 0.23 Gy, respectively. The effect on lymphocytes of internal radiation induced by (131)I therapy is minimal when based on the frequencies of CA 1 year after the treatment, maintaining a higher quality of life for DTC patients receiving rhTSH-aided therapy.

Outpatient radioiodine therapy for thyroid cancer: a safe nuclear medicine procedure.

PURPOSES: To evaluate the dosimetric effect of outpatient radioiodine therapy for thyroid cancer in members of a patient's family and their living environment, when using iodine-131 doses reaching 7.4 GBq. The following parameters were thus defined: (a) whole-body radiation doses to caregivers, (b) the production of contaminated solid waste, and (c) radiation potential and surface contamination within patients' living quarters. METHODS: In total, 100 patients were treated on an outpatient basis, taking into consideration their acceptable living conditions, interests, and willingness to comply with medical and radiation safety guidelines. Both the caregivers and the radiation dose potentiality inside patients' residences were monitored by using thermoluminescent dosimeters. Surface contamination and contaminated solid wastes were identified and measured with a Geiger-Müller detector. RESULTS: A total of 90 monitored individuals received a mean dose of 0.27 (±0.28) mSv, and the maximum dose registered was 1.6 mSv. The mean value for the potential dose within all living quarters was 0.31 (±0.34) mSv, and the mean value per monitored surface was 5.58 Bq/cm(2) for all the 1659 points measured. The overall production of contaminated solid wastes was at a low level, being about 3 times less than the exemption level indicated by the International Atomic Energy Agency. CONCLUSIONS: This study indicates that the treatment of thyroid cancer by applying radioiodine activities up to 7.4 GBq, on an outpatient basis, is a safe procedure, especially when supervised by qualified professionals. This alternative therapy should be a topic for careful discussion considering the high potential for reducing costs in healthcare and improving patient acceptance.

Determinação dos fatores de recuperação do 111In e do 99mTc na quantificação de atividade com imagens SPECT / Determination of 111In and 99mTc recovery in the quantification of activity with SPECT imaging

OBJETIVO: Determinar, experimentalmente, os coeficientes de recuperação do 111In e do 99mTc usando imagens SPECT. MATERIAIS E MÉTODOS: Quatro diferentes concentrações de 111In e de 99mTc foram usadas para quantificar a atividade em esferas de diferentes tamanhos. As imagens foram obtidas com um equipamento híbrido SPECT/CT, com dois detectores. A reconstrução das imagens foi realizada usando o método iterativo ordered subset expectation maximization (OSEM). A correção de atenuação foi realizada com o uso de um mapa de atenuação e a correção de espalhamento foi realizada usando a técnica das janelas de energia. RESULTADOS: Os resultados mostraram que o efeito do volume parcial foi observado de forma mais significativa para as esferas com volume < 6 ml. Para o 111In, os resultados mostram uma dependência com relação às concentrações usadas nas esferas e ao nível de background usado. Para o 99mTc, pôde-se observar uma tendência à subestimação dos resultados quando os níveis mais altos de background foram utilizados. CONCLUSÃO: É necessário usar os fatores de correção para compensar o efeito do volume parcial em objetos com volume < 6 ml para ambos os radionuclídeos. A subtração das contagens espúrias presentes nas imagens SPECT foi o fator que mais influenciou na quantificação da atividade nessas esferas.

OBJECTIVE: To experimentally determine the 99mTc and 111In activity recovery coefficients in SPECT imaging. MATERIALS AND METHODS: Four different 99mTc and 111In concentrations were utilized for quantifying activity in spheres of four different sizes. Images were obtained with a hybrid dual-head SPECT-CT imaging system. The ordered subset expectation maximization (OSEM) iterative method was utilized for images reconstruction. An attenuation map was utilized for attenuation correction, and the multiple energy window technique for scattering correction. RESULTS: Results for spheres < 6 ml in volume were significantly affected by the partial volume effect. For 111In quantification, results show a dependence on sphere concentrations and background levels. For 99mTc quantification, there was a tendency towards values underestimation with higher background levels. CONCLUSION: Correction factors must be utilized for compensating the partial volume effect on objects with < 6 ml in volume for both radionuclides. Background subtraction to compensate spurious count present on SPECT images has a significant influence on the quantification of activity, especially for the smaller objects.

[Radioiodine therapy of differentiated thyroid cancer: radiologic impact of out-patient treatment with 100 to 150 mCi Iodine-131 activities]. / Radioiodoterapia do carcinoma diferenciado da tireoide: impacto radiológico da liberação hospitalar de pacientes com atividades entre 100 e 150 mCi de iodo-131.

PURPOSE: To evaluate exposure and dosimetry to family members and environment due to outpatient radioiodine therapy of differentiated thyroid carcinoma. METHODS: Twenty patients were treated with 100-150mCi of iodine-131 on an out-patient basis. Family members dosimetry (n = 27) and potential doses inside the house were measured with thermoluminescent dosimeters. Surface contamination and radioactive wastes were also monitored. RESULTS: Less than 1.0 mSv doses were found in 26 co-habitants and 2.8 mSv in a single case (inferior to the acceptable value of 5.0 mSv/procedure). Potential doses in the houses were inferior to 0.25 mSv, excluding the patients bedroom (mean value = 0.69 mSv). Surface contamination (mean = 4.2 Bq.cm-2) were below clearance levels. Radioactive wastes generated had a volume of 2.5 liters and a total activity estimated in 90 microCi, with a calculated exposure close to the background radiation levels. CONCLUSIONS: No radiological impact was detected after iodine therapy with 100-150 mCi on an out-patient basis followed by experienced professionals.

Could the treatment of differentiated thyroid carcinoma with 3.7 and 5.55 GBq of (131I)NaI, on an outpatient basis, be safe?

OBJECTIVES: The first objective of this study was to evaluate the radiological impact on relatives and the environment because of outpatient treatment of differentiated thyroid carcinoma with 3.7 and 5.55 GBq of (131I)NaI. The second objective was to determine, analyze, and evaluate whole-body radiation dose to caregivers, the production of contaminated solid waste, and the potentiality of radiation dose and surface contamination existing inside patients' households. METHODS: Twenty patients were treated on an outpatient basis, taking into consideration their acceptable living conditions, interests, and willingness to comply with medical and radiation-safety guidelines. The caregivers themselves, as well as the potentiality of the radiation dose inside patients' residences, were monitored with a thermo-luminescence dosimeter. Surface contamination and contaminated solid wastes were identified and measured by using a Geiger-Müller detector. RESULTS AND DISCUSSION: Twenty-six monitored individuals received accumulated effective radiation doses of less than 1.0 mSv, and only one 2.8 mSv, throughout the 7 days of measurement. The maximum registered value for the potential of radiation dose inside all living areas was 1.30 mSv. The monitored surface contamination inside patients' dwellings showed a mean value of 4.2 Bq/cm for all surfaces found to be contaminated. A total of 2.5 l of contaminated solid waste was generated by the patients with 3.33 MBq of all estimated activity. CONCLUSION: This study revealed that the treatment of differentiated thyroid carcinoma with 3.7 and 5.55 GBq of (131I)NaI, on an outpatient basis, can be safe when overseen by qualified professionals and with an adapted radiation-protection guideline. Even considering the radioiodine activity level and the dosimetric methodology applied here, negligible human exposure and a nonmeasurable radiological impact to the human environment were found.

Radioiodoterapia do carcinoma diferenciado da tireoide: impacto radiológico da liberação hospitalar de pacientes com atividades entre 100 e 150 mCi de iodo-131 / Radioiodine therapy of differentiated thyroid cancer: radiologic impact of out-patient treatment with 100 to 150 mCi Iodine-131 activities

OBJETIVO: Determinar exposições decorrentes da radioiodoterapia ambulatorial do carcinoma diferenciado da tireoide (CDT) sobre os familiares dos pacientes e o meio ambiente. MÉTODOS: Administraram-se 100 a 150 mCi de (131I)NaI para tratamento ambulatorial de 20 pacientes com CDT. Monitorizaram-se com dosímetros termoluminescentes as doses de radiação recebidas por familiares (n = 27) e potenciais de dose nas residências. Também foram monitorizadas contaminação de superfície e rejeitos radioativos. RESULTADOS: Registraram-se doses < 1,0 mSv em 26 acompanhantes e 2,8 mSv em um caso, inferiores ao aceitável para exposições médicas (5,0 mSv/procedimento). Excetuando-se o quarto dos pacientes (média = 0,69 mSv), determinou-se potencial de dose nas residências < 0,25 mSv. A contaminação de superfícies (4,2 Bq.cm-2) não ultrapassou níveis de liberação, sem representar riscos mesmo em simulações do pior cenário. Os rejeitos radioativos tiveram volume de 2,5 litros e atividade estimada em 90 µCi (média = 4,5 µCi/paciente). CONCLUSÕES: Não foi constatado impacto radiológico ao meio ambiente ou aos familiares de pacientes tratados ambulatorialmente com 100 a 150 mCi de iodo-131 e acompanhados por profissionais qualificados.

PURPOSE:To evaluate exposure and dosimetry to family members and environment due to outpatient radioiodine therapy of differentiated thyroid carcinoma. METHODS: Twenty patients were treated with 100-150mCi of iodine-131 on an out-patient basis. Family members dosimetry (n = 27) and potential doses inside the house were measured with thermoluminescent dosimeters. Surface contamination and radioactive wastes were also monitored. RESULTS: Less than 1.0 mSv doses were found in 26 co-habitants and 2.8 mSv in a single case (inferior to the acceptable value of 5.0 mSv/procedure). Potential doses in the houses were inferior to 0.25 mSv, excluding the patients bedroom (mean value = 0.69 mSv). Surface contamination (mean = 4.2 Bq.cm-2) were below clearance levels. Radioactive wastes generated had a volume of 2.5 liters and a total activity estimated in 90 µCi, with a calculated exposure close to the background radiation levels. CONCLUSIONS: No radiological impact was detected after iodine therapy with 100-150 mCi on an out-patient basis followed by experienced professionals.

Evaluation of the cytogenetic effects of (131)I preceded by recombinant human thyrotropin (rhTSH) in peripheral lymphocytes of Wistar rats.

The present study was carried out to investigate the cytogenetic effects of therapeutic exposure to radioiodine preceded by rhTSH in an animal model. Three groups of Wistar rats (n = 6) were used: one group was treated only with (131)I (11.1 MBq/animal); the other two groups received rhTSH (1.2 mug/rat of either Thyrogen or rhTSH-IPEN, respectively) 24 h before administration of radioiodine. The percentage of lymphocytes with chromosome aberrations and the average number of aberrations and of dicentrics per cell were determined on blood samples collected 24 h, 7 and 30 days after administration of (131)I. The data show that the treatment with radioiodine alone or associated with rhTSH resulted in a greater quantity of chromosome alterations in relation to basal values after 24 h, with a gradual decline after 7 and 30 days of treatment. An increase in chromosome alterations was also seen after rhTSH treatment alone. Neither of the treatments, i.e., with (131)I alone or associated with hormone, resulted in an aneugenic effect or influenced the kinetics of cellular proliferation in rat blood lymphocytes. There was no significant difference between the cytogenetic effects of Thyrogen and rhTSH-IPEN treatment. These data suggest that the treatment with radioiodine, associated or not with rhTSH, affects to a limited extent a relatively small number of cells although the occurrence of late stochastic effects could not be discarded.

Estudo do efeito do uso de colimador na sonda gama utilizada em cirurgia radioguiada / Study of the effect of using a collimator on a gamma probe in radioguided surgery

OBJETIVO: O objetivo deste trabalho consiste em estudar a influência da resolução espacial da sonda gama Europrobe que é utilizada em cirurgia radioguiada. MATERIAIS E MÉTODOS: Na técnica de cirurgia radioguiada, após a injeção de um radiotraçador no tumor primário, é utilizada uma sonda detectora de radiação gama a fim de determinar a localização do linfonodo sentinela. Para simular a região dos pontos de injeção do radiotraçador e o linfonodo sentinela, duas fontes de Tc-99m, com 20,42 MBq e 0,70 MBq, foram posicionadas no interior de um recipiente preenchido com água. Em seguida, com a janela de entrada da sonda coberta com um colimador, realizou-se varredura sobre a superfície da água. Assim, foi possível registrar a taxa de contagens variando-se a distância lateral da sonda em relação às duas fontes, as quais foram separadas por uma distância variando entre 30 mm e 60 mm. RESULTADOS: Os resultados mostraram que o uso do colimador contribui para melhorar a resolução espacial da sonda, permitindo a identificação do linfonodo sentinela distante até 30 mm do ponto de injeção. CONCLUSÃO: Esse estudo permite concluir que a sonda Europrobe, quando utilizada com capa colimadora com orifício central de 3,5 mm de diâmetro, é capaz de identificar o linfonodo sentinela posicionado a até 30 mm de distância em relação à região do ponto de injeção do radiotraçador.

OBJECTIVE: The aim of the present study is to evaluate the performance of the Europrobe gamma probe spatial resolution in radioguided surgery. MATERIALS AND METHODS: In the radioguided surgery technique, after a radiotracer injection into the primary tumor, a gamma detector probe is utilized to determine the localization of the sentinel lymph node. In order to simulate the region of the radiotracer injection the sentinel lymph node, two Tc-99m sources, with 20.42 MBq and 0.70 MBq, were positioned in a water-filled tank. With a collimator cap attached to the probe, scans over the water surface were made. So, the count rate was measured by means of lateral displacement of the probe in relation to the both sources with distances ranging between 30 mm and 60 mm. RESULTS: Results showed that the use of the collimator contributes to improve the spatial resolution of the probe allowing the identification of a sentinel lymph node within a distance up to 30 mm from the radiotracer injection point. CONCLUSION: The utilization of a collimator cap with a 3.5 mm diameter central orifice on a Europrobe gamma probe, allows the identification of a sentinel lymph node within a distance up to 30 mm from the radiotracer injection point.

Retrospective evaluation of bone pain palliation after samarium-153-EDTMP therapy.

PURPOSE: The aim of this study was to evaluate the degree of metastatic bone pain palliation and medullar toxicity associated with samarium-153-EDTMP treatment. METHODS: Seventy-three patients with metastatic bone pain having previously undergone therapy with samarium-153-EDTMP (1 mCi/kg) were retrospectively evaluated. Routine follow-up included pain evaluation and blood counts for 2 months after treatment. Pain was evaluated using a subjective scale (from 0 to 10) before and for 8 weeks after the treatment. Blood counts were obtained before treatment and once a week for 2 months during follow-up. Dosimetry, based upon the urinary excretion of the isotope, was estimated in 41 individuals, and the resulting radiation absorbed doses were correlated with hematological data. RESULTS: Reduction in pain scores of 75% to 100% was obtained in 36 patients (49%), with a decrease of 50% to 75%, 25% to 50%, and 0% to 25% in, respectively, 20 (27%), 10 (14%), and 7 (10%) patients. There was no significant relationship between the pain response and location of the primary tumor (breast or prostate cancer). Mild to moderate myelosuppression was noted in 75.3% of patients, usually with hematological recovery at 8 weeks. The mean bone marrow dose was 347 +/- 65 cGy, and only a weak correlation was found between absorbed dose and myelosuppression (Pearson coefficient = .4). CONCLUSIONS: Samarium-153-EDTMP is a valuable method for metastatic bone pain palliation. A mild to moderate and transitory myelosuppression is the main toxicity observed after samarium therapy, showing a weak correlation with dosimetric measures.

Retrospective evaluation of bone pain palliation after samarium-153-EDTMP therapy

OBJETIVO: O presente trabalho teve por objetivo avaliar o efeito paliativo da dor e a toxicidade medular associados ao tratamento com Samário-153-EDTMP em pacientes com metástases ósseas. MÉTODOS: O estudo foi realizado de forma retrospectiva, a partir do levantamento de prontuário de 178 pacientes submetidos a tratamento com 1mCi/kg de 153Sm-EDTMP devido à dor por metástases ósseas. Os prontuários de 73 pacientes foram considerados adequados para análise dos parâmetros clínicos (intensidade da dor) e laboratoriais (hemograma). A intensidade da dor foi avaliada em escala de 0 a 10 pelo próprio paciente, antes e durante 8 semanas após o tratamento. Hemograma completo foi realizado antes do tratamento e a cada semana nas 8 semanas seguintes. Estudos de dosimetria foram realizados em 41 dos 73 pacientes, baseados na excreção urinária e retenção do radioisótopo, sendo a dose de radiação absorvida correlacionada à toxicidade medular. RESULTADOS: Redução importante na intensidade da dor (diminuição de 75 a 100% do basal) foi constatada em 36 pacientes (49%), com redução de 50-75%, 25-50% e 0-25% em, respectivamente, 20 (27%), 10 (14%) e 7 (10%) casos. Não se observou variação significativa da resposta entre os pacientes com tumor primário de mama (n=29) ou de próstata (n=36). Toxicidade medular foi observada em 75,3% dos pacientes (71,2% com leucopenia e 53,4% com plaquetopenia), em geral de grau leve a moderado e com recuperação ao término da 8º semana. A dose média de medula foi de 347±65 cGy, havendo baixa correlação entre a dosimetria medular e a queda da contagem de leucócitos (coeficiente de correlação linear de 0,40) ou de plaquetas (coeficiente de correlação linear = 0,48). CONCLUSÕES: O tratamento com Samário-153-EDTMP permitiu um adequado controle da dor por metástases ósseas, com significativa redução na intensidade da dor. A toxicidade medular transitória foi a principal reação adversa observada, em geral de grau leve a moderado, apresentando baixa correlação com as medidas dosimétricas.

Medicina do trabalho e os princípios básicos de proteção radiológica: antigos e novos paradigmas / Occupational Medicine and the Basic Principles of Radiological Protection - Old and New Paradigms

As relações entre trabalhadores, pacientes e médicos diante dos princípios básicos de proteção radiológica, têm, neste trabalho, uma introdução histórica que dá ênfase ao seu desenvolvimento até se chegar ao período atual. É abordada a evolução dos conhecimentos científicos quanto aos benefícios e malefícios advindo da utilização das radiações ionizantes nas atividades humanas. Tais princípios (justificação, otimização e limitação) são tratados de modo a fornecer uma visão ampla de seus campos de aplicação. No princípio da otimização são introduzidas as técnicas de ajuda para a tomada de decisão utilizadas em proteção radiológica. No princípio da limitação de doses foi introduzido o conceito de limite vinculado a um determinado segmento da população ou a uma determinada atividade humana. Com relação ao atual relacionamento entre equipe médica e paciente, discute-se a mudança de filosofia no que diz respeito à dose de radiação ministrada, que deve ser mínima com relação aos objetivos de diagnose ou cura. Para tanto devem ser seguidas as recomendações da ICRP - International Commision on Radiological Protection. A radiação pode trazer benefícios desde que utilizada com racionalidade, eficiência e cuidados. A radiação não deve ser temida, mas respeitada.

Comparison of specific absorbed fractions (SAF) in the Brazilian adult male and the reference man phantoms.

The mathematical phantom of the Brazilian man was developed because many anatomical differences exist between South Americans, Europeans and North Americans. The objective of this work was to compare specific absorbed fractions (SAF) obtained for a model of the Brazilian adult male with those for the reference adult calculated by Snyder et al. in 1974 and to evaluate the importance of these new values in calculating radiation doses in diagnosis and therapy. The length and mass of the total body for the Brazilian man phantom were obtained from tables provided by the Brazilian government (IBGE) in which the masses of organs were measured atautopsy. Monte Carlo methods (using the ALGAM-97 computer code) were applied to calculate SAF for internal organs and the total body. The mathematical phantom designed by Snyder et al. represents very closely Reference Man, as defined in ICRP publication 23. SAF for the whole body were not more than 15% different between the two phantoms. The differences between both models are more significant for individual organs. When the source organ is the lung and red marrow is the target, for initial photon energy of 10 keV, the results obtained indicate that marrow receives 64% more dose in Brazilian model than in the Reference Man model. Eighty tables were made for 97 distinct organs (target-source) and the comparison made between the, Brazilian man and Reference man.

Comparative in vivo and in vitro study of the cytogenetic effects of 153Sm-EDTMP in lymphocytes of patients with bone metastases.

153Sm-EDTMP is a radiopharmaceutical used in nuclear medicine for relief of metastatic bone pain with promising results, but there are few studies about the effects of 153Sm-EDTMP in human cells. This study was conducted for the evaluation of the cytogenetic effects of 153Sm-EDTMP in blood lymphocytes from patients with bone metastases (without previous radio or chemotherapy), using the chromosome aberration technique. The degree of cytological damage found in in vivo blood cells of patients was compared with those found in in vitro in an adjusted dose-response curve. Blood samples were collected before and 1 hr after the administration of 153Sm-EDTMP(about 42.31 MBq/kg). The frequency of structural chromosome aberration per cell observed in 1 hr samples (0.054+/-0.035 CA/cell) was higher than basal ones (0.031+/-0.026 CA/cell), although this difference was not statistically significant (p= 0.101). For in vitro assay, blood samples were exposed to different concentrations of 153Sm-EDTMP, during 1 hr (0.37-1.11 MBq/ml). An increase in the frequency of chromosome aberration per cell as a function of the radioactive concentration was found. The data were adjusted by linear regression model (Y= 3.52+/-2.24 x 10(-2) + 11.15+/-3.46 x 10(-2) X). The frequency of aberration/cell found in vivo was 0.054 and for the same activity in vitro was 0.098, this difference being statistically significant (p = 0.02). This result may be related to blood clearance, osteoblastic activity and individual variability. For a more accurate analysis, the study of more donors is necessary.

Exposure of persons accompanying patients in nuclear medicine departments.

Patient who receives a radiopharmaceutical remains radioactive for hours or even days and so represents a potential hazard to other individuals. Thus, in nuclear medicine departments, apart from the personnel who are occupationally exposed to ionizing radiation, protection rules must be observed for members of the public, in particular persons accompanying patients. The purpose of this work was to evaluate the absorbed dose levels, which persons accompanying patients are exposed to. Integral dose studies were carried out in three nuclear medicine departments, in Brazil. Dose levels are presented, and issues are discussed with regard to the presence of members of the public in waiting areas of such departments.