RESUMEN
ABSTRACT Objective: To evaluate the effects of positive expiratory pressure (PEP) on pulmonary epithelial membrane permeability in healthy subjects. Methods: We evaluated a cohort of 30 healthy subjects (15 males and 15 females) with a mean age of 28.3 ± 5.4 years, a mean FEV1/FVC ratio of 0.89 ± 0.14, and a mean FEV1 of 98.5 ± 13.1% of predicted. Subjects underwent technetium-99m-labeled diethylenetriaminepentaacetic acid (99mTc-DTPA) radioaerosol inhalation lung scintigraphy in two stages: during spontaneous breathing; and while breathing through a PEP mask at one of three PEP levels-10 cmH2O (n = 10), 15 cmH2O (n = 10), and 20 cmH2O (n = 10). The 99mTc-DTPA was nebulized for 3 min, and its clearance was recorded by scintigraphy over a 30-min period during spontaneous breathing and over a 30-min period during breathing through a PEP mask. Results: The pulmonary clearance of 99mTc-DTPA was significantly shorter when PEP was applied-at 10 cmH2O (p = 0.044), 15 cmH2O (p = 0.044), and 20 cmH2O (p = 0.004)-in comparison with that observed during spontaneous breathing. Conclusions: Our findings indicate that PEP, at the levels tested, is able to induce an increase in pulmonary epithelial membrane permeability and lung volume in healthy subjects.
RESUMO Objetivo: Avaliar os efeitos da pressão expiratória positiva (PEP) na permeabilidade da membrana epitelial pulmonar em indivíduos saudáveis. Métodos: Foi avaliada uma coorte de 30 indivíduos saudáveis (15 homens e 15 mulheres), com média de idade de 28,3 ± 5,4 anos, média da relação VEF1/CVF de 0,89 ± 0,14 e média de VEF1 de 98,5 ± 13,1% do previsto. Os indivíduos foram submetidos a cintilografia pulmonar por inalação de radioaerossol de ácido dietilenotriaminopentacético marcado com tecnécio-99m (99mTc-DTPA em inglês) em dois estágios: durante respiração espontânea e durante respiração com uma máscara de PEP de 10 cmH2O (n = 10), 15 cmH2O (n = 10) ou 20 cmH2O (n = 10). O 99mTc-DTPA foi nebulizado por 3 min, e sua depuração foi registrada por cintilografia por um período de 30 min durante respiração espontânea e por um período de 30 min durante a respiração com uma máscara de PEP. Resultados: A depuração pulmonar do 99mTc-DTPA foi significativamente menor quando PEP foi aplicada a 10 cmH2O (p = 0,044), 15 cmH2O (p = 0,044) e 20 cmH2O (p = 0,004), em comparação com a observada durante a respiração espontânea. Conclusões: Nossos achados indicam que o uso de PEP nos níveis testados pode induzir um aumento na permeabilidade da membrana epitelial pulmonar e no volume pulmonar em indivíduos saudáveis.
Asunto(s)
Humanos , Femenino , Adulto , Pulmón/metabolismo , Respiración con Presión Positiva/métodos , Radiofármacos/farmacocinética , Pentetato de Tecnecio Tc 99m/farmacocinética , Pulmón/fisiología , Tasa de Depuración Metabólica , Permeabilidad , Alveolos Pulmonares/metabolismo , Radiofármacos/administración & dosificación , Pentetato de Tecnecio Tc 99m/administración & dosificaciónRESUMEN
OBJECTIVE:: To evaluate the effects of positive expiratory pressure (PEP) on pulmonary epithelial membrane permeability in healthy subjects. METHODS:: We evaluated a cohort of 30 healthy subjects (15 males and 15 females) with a mean age of 28.3 ± 5.4 years, a mean FEV1/FVC ratio of 0.89 ± 0.14, and a mean FEV1 of 98.5 ± 13.1% of predicted. Subjects underwent technetium-99m-labeled diethylenetriaminepentaacetic acid (99mTc-DTPA) radioaerosol inhalation lung scintigraphy in two stages: during spontaneous breathing; and while breathing through a PEP mask at one of three PEP levels-10 cmH2O (n = 10), 15 cmH2O (n = 10), and 20 cmH2O (n = 10). The 99mTc-DTPA was nebulized for 3 min, and its clearance was recorded by scintigraphy over a 30-min period during spontaneous breathing and over a 30-min period during breathing through a PEP mask. RESULTS:: The pulmonary clearance of 99mTc-DTPA was significantly shorter when PEP was applied-at 10 cmH2O (p = 0.044), 15 cmH2O (p = 0.044), and 20 cmH2O (p = 0.004)-in comparison with that observed during spontaneous breathing. CONCLUSIONS:: Our findings indicate that PEP, at the levels tested, is able to induce an increase in pulmonary epithelial membrane permeability and lung volume in healthy subjects. OBJETIVO:: Avaliar os efeitos da pressão expiratória positiva (PEP) na permeabilidade da membrana epitelial pulmonar em indivíduos saudáveis. MÉTODOS:: Foi avaliada uma coorte de 30 indivíduos saudáveis (15 homens e 15 mulheres), com média de idade de 28,3 ± 5,4 anos, média da relação VEF1/CVF de 0,89 ± 0,14 e média de VEF1 de 98,5 ± 13,1% do previsto. Os indivíduos foram submetidos a cintilografia pulmonar por inalação de radioaerossol de ácido dietilenotriaminopentacético marcado com tecnécio-99m (99mTc-DTPA em inglês) em dois estágios: durante respiração espontânea e durante respiração com uma máscara de PEP de 10 cmH2O (n = 10), 15 cmH2O (n = 10) ou 20 cmH2O (n = 10). O 99mTc-DTPA foi nebulizado por 3 min, e sua depuração foi registrada por cintilografia por um período de 30 min durante respiração espontânea e por um período de 30 min durante a respiração com uma máscara de PEP. RESULTADOS:: A depuração pulmonar do 99mTc-DTPA foi significativamente menor quando PEP foi aplicada a 10 cmH2O (p = 0,044), 15 cmH2O (p = 0,044) e 20 cmH2O (p = 0,004), em comparação com a observada durante a respiração espontânea. CONCLUSÕES:: Nossos achados indicam que o uso de PEP nos níveis testados pode induzir um aumento na permeabilidade da membrana epitelial pulmonar e no volume pulmonar em indivíduos saudáveis.
Asunto(s)
Pulmón/metabolismo , Respiración con Presión Positiva/métodos , Radiofármacos/farmacocinética , Pentetato de Tecnecio Tc 99m/farmacocinética , Adulto , Femenino , Humanos , Pulmón/fisiología , Tasa de Depuración Metabólica , Permeabilidad , Alveolos Pulmonares/metabolismo , Radiofármacos/administración & dosificación , Pentetato de Tecnecio Tc 99m/administración & dosificaciónRESUMEN
BACKGROUND: Despite the clinical improvements attributed to noninvasive ventilation (NIV) during asthma crises, and the well established effects of nebulization, there are few studies on the effects of these interventions together. We hypothesized that nebulization coupled to NIV should raise radio-aerosol pulmonary deposition in asthmatics. The aims of this study were to assess the effects of coupling ß-agonist nebulization and NIV during asthma exacerbations on radio-aerosol pulmonary deposition, using scintigraphy and cardiopulmonary parameters, to correlate pulmonary function with radio-aerosol deposition index, radio-aerosol penetration index, and pulmonary clearance. METHODS: In this controlled trial, 21 adults with moderate to severe asthma attack were randomized to a control group (n = 11) or experimental group (NIV + nebulizer group, n = 10). All subjects inhaled bronchodilators for 9 minutes, and after particles were counted with a gamma camera to analyze regions of interest and pulmonary clearance at 0, 15, 30, 45, and 60 min. RESULTS: Breathing frequency (P = < .001) and minute ventilation (P = .01) were reduced, and tidal volume was increased (P = .01) in the NIV + nebulizer group, compared with the control group. The NIV + nebulizer group had improvement from baseline values, compared to the control group in the following parameters: FEV(1) 46.7 ± 0.5% of predicted vs 29.8 ± 8.9% of predicted, P = .02), FVC (41.2 ± 1.5% of predicted vs 23.2 ± 7.1% of predicted, P = .02), peak expiratory flow (67.3 ± 38.3% of predicted vs 26.9 ± 12.1% of predicted, P = .01), and inspiratory capacity (54.9 ± 28.8% of predicted vs 31.2 ± 9.1% of predicted, P = .01). No differences were observed between groups regarding radio-aerosol deposition index or pulmonary clearance. Negative correlations were found between FEV1, forced expiratory flow during the middle half of the FVC maneuver (FEF(25-75%)), inspiratory capacity, and radio-aerosol penetration index. CONCLUSIONS: Coupling nebulization and NIV during asthma exacerbation did not improve radio-aerosol pulmonary deposition, but we observed clinical improvement of pulmonary function in these subjects. (ClinicalTrials.gov registration NCT01012050).
Asunto(s)
Agonistas Adrenérgicos beta/administración & dosificación , Asma/fisiopatología , Asma/terapia , Broncodilatadores/administración & dosificación , Presión de las Vías Aéreas Positiva Contínua , Radiofármacos , Pentetato de Tecnecio Tc 99m , Adolescente , Agonistas Adrenérgicos beta/farmacocinética , Adulto , Anciano , Broncodilatadores/farmacocinética , Femenino , Volumen Espiratorio Forzado , Humanos , Masculino , Persona de Mediana Edad , Nebulizadores y Vaporizadores , Ápice del Flujo Espiratorio , Radiofármacos/farmacocinética , Frecuencia Respiratoria , Pentetato de Tecnecio Tc 99m/farmacocinética , Volumen de Ventilación Pulmonar , Adulto JovenRESUMEN
OBJECTIVE: The aim of this study was to compare the renal function measured with either 99mTc-DTPA or 99mTc-EC dynamic scintigraphies with that measured using 99mTc-DMSA static scintigraphy. METHODS: the values of relative renal function measured in 111 renal dynamic scintigraphies performed either with 99mTc-DTPA (55 studies) or with 99mTc-EC (56 studies) were compared with the relative function measured using 99mTc-DMSA static scintigraphy performed within a 1-month period. The comparisons were performed using Wilcoxon signed rank test. The number of 99mTc-DTPA and 99mTc-EC studies that presented relative renal function different by more than 5% from that measured with 99mTc-DMSA, using chi square test were also compared. RESULTS: the relative renal function measured with 99mTc-EC is not statistically different from that measured with 99mTc-DMSA (p = 0.97). The relative renal function measured with 99mTc-DTPA was statistically different from that measured using 99mTc-DMSA, but with a borderline statistical significance (p = 0.05). The number of studies with relative renal function different by more than 5% from that measured with 99mTc-DMSA is higher for the 99mTc-DTPA scintigraphy (p = 0.04) than for 99mTc-EC. CONCLUSION: the relative renal function measured with 99mTc-EC dynamic scintigraphy is comparable with that measured with 99mTc-DMSA static scintigraphy, while the relative renal function measured with 99mTc-DTPA dynamic scintigraphy presents a significant statistical difference from that measured with 99mTc-DMSA static scintigraphy.
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Radiofármacos , Obstrucción de la Arteria Renal/diagnóstico por imagen , Ácido Dimercaptosuccínico de Tecnecio Tc 99m , Pentetato de Tecnecio Tc 99m , Adolescente , Adulto , Anciano , Niño , Preescolar , Femenino , Humanos , Interpretación de Imagen Asistida por Computador , Lactante , Recién Nacido , Pruebas de Función Renal/métodos , Masculino , Persona de Mediana Edad , Cintigrafía , Radiofármacos/farmacocinética , Reproducibilidad de los Resultados , Ácido Dimercaptosuccínico de Tecnecio Tc 99m/farmacocinética , Pentetato de Tecnecio Tc 99m/farmacocinéticaRESUMEN
UNLABELLED: Nebulization associated with noninvasive ventilation is used in emergency services and intensive care units. PURPOSES: To compare pulmonary radioaerosol deposition during jet nebulization associated to noninvasive ventilation versus spontaneous breathing nebulization; to measure the rate of lung depuration and the correlation between lung deposition, inspiratory flow and tidal volume (V(t)) using scintigraphy. SUBJECTS: Thirteen healthy volunteers (with normal spirometry), mean age (23.3+/-1.49) years, body mass index 21.2+/-2.3 kg/m(2). METHODS: Nebulization was performed in spontaneous breathing and associated with bi-level noninvasive ventilation (inspiratory pressure=12 cm H(2)O, expiratory pressure=5 cm H(2)O). The radioaerosol used in the nebulization was technetium (Tc99m) with diethylene triamine penta acetic acid, generated over a period of 9 min in a jet nebulizer. Analysis was performed through scintigraphy. Statistical analysis was performed by analysis of variance (for repeated measures), Bonferroni method, Student's t-test and Person's correlation. RESULTS: There was a decrease in radioaerosol lung deposition with nebulization associated to noninvasive ventilation (mean counts in spontaneous breathing 200,510+11,012 and mean counts in noninvasive ventilation 106,093+2811 (P<0.001). During spontaneous breathing nebulization there was a significant correlation between V(t) and radioaerosol deposition (r=0.565, P<0.05), also between inspiratory flow and radioaerosol deposition in the lungs (r=0.141, P<0.05). However, there was no correlation between V(t) and pulmonary deposition of radioaerosol in bi-level noninvasive ventilation nebulization (r=0.082). CONCLUSION: During nebulization with noninvasive ventilation in healthy volunteers, there was an increase in V(t) associated to a higher inspiratory flow rate, without resulting in a significant increase in pulmonary radioaerosol deposition.
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Pulmón/metabolismo , Nebulizadores y Vaporizadores , Terapia Respiratoria/métodos , Pentetato de Tecnecio Tc 99m/farmacocinética , Administración por Inhalación , Adulto , Aerosoles , Femenino , Humanos , Pulmón/diagnóstico por imagen , Masculino , Cintigrafía , Pruebas de Función Respiratoria , Pentetato de Tecnecio Tc 99m/administración & dosificaciónRESUMEN
PURPOSE: To evaluate pulmonary epithelial permeability using 99mTc-DTPA scintigraphy in patients treated with bleomycin-containing regimens. MATERIAL AND METHODS: Twelve non-smoking chemotherapy-naïve patients with no clinical or radiological evidence of pulmonary disease and treated with bleomycin-containing chemotherapy were tested with 99mTc-DTPA scintigraphy before the first cycle and every 3 weeks until the third month after the end of chemotherapy (total cumulative dose of bleomycin 347.9 mg). RESULTS: Pretreatment values (T1/2 74.93 minutes) of 99mTc-DTPA scintigraphy were significantly higher than those obtained after the total dose of bleomycin (T1/2 51.00 minutes) (p < 0.001). This difference was more important in the later evaluations especially, on the third week and third month measures after discontinuing treatment (p < 0.001). All the tests of Within-Subjects Effects were significant (p < 0.001). Comparing pretreatment and post-treatment scintigraphies the mean T1/2 99mTc-DTPA values decreased as the bleomycin dose increased. CONCLUSION: We conclude that cumulative bleomycin doses are related to increased pulmonary epithelial permeability at a dose of 256.5 mg. However, whether this is related to clinical toxicity is uncertain and large, multi-center prospective studies are needed.
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Bleomicina/efectos adversos , Mucosa Respiratoria/efectos de los fármacos , Mucosa Respiratoria/diagnóstico por imagen , Pentetato de Tecnecio Tc 99m , Adulto , Antibióticos Antineoplásicos/efectos adversos , Antibióticos Antineoplásicos/uso terapéutico , Bleomicina/uso terapéutico , Femenino , Enfermedad de Hodgkin/tratamiento farmacológico , Humanos , Masculino , Neoplasias Ováricas/tratamiento farmacológico , Permeabilidad/efectos de los fármacos , Cintigrafía , Radiofármacos/farmacocinética , Mucosa Respiratoria/metabolismo , Pentetato de Tecnecio Tc 99m/farmacocinética , Neoplasias Testiculares/tratamiento farmacológicoRESUMEN
Two radioaerosol preparations, TechneScan -DTPA (99mTc-DTPA, 40 mCi/3 ml; IPEN-CNEN, São Paulo, SP, Brazil) and TechneScan -DTPA/AEROSOL (99mTc-DTPA/A, 15 mCi/1.5 ml with 0.5 ml ethanol; Mallinckrodt Medical, St. Louis, MO, USA), were compared in pulmonary ventilation studies in terms of total radiocounts and clearance after inhalation. An aerosol with ethanol is supposed to better distribute the radioparticles in the lungs. Twenty normal nonsmoking volunteers (10 men and 10 women), mean age of 23.2 years (range: 20 to 35 years), were studied. Images were obtained immediately and 30, 60 and 90 min after inhalation. Total and regional counts were obtained and the clearance half-lives of both lungs were determined. There was no difference in total counts between the two types of radioaerosol at any time (mean of approximately 188,000 cpm for male and female subjects at time zero in both aerosols). The highest count was obtained in the middle region of both lungs (P<0.001) with both preparations. The clearance half-life did not differ between aerosols (mean of ~80-88 min for male and female subjects for both aerosols). Small nonsignificant regional differences were observed. No differences between genders or between right and left lung were observed. 99mTc-DTPA/A generated the highest output of radioaerosol. 99mTc-DTPA with alcohol costs approximately five times more than the aerosol without alcohol. The present results show that either kind of aerosol may be adopted routinely for use in pulmonary examinations without affecting diagnosis. We suggest that the amount of 740 mBq (20 mCi) of 99mTc-DTPA in 1.5 ml saline can be used for routine examinations resulting in reduction of costs in pulmonary ventilation studies without diagnostic impairment.
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Pulmón/diagnóstico por imagen , Radiofármacos/farmacocinética , Pentetato de Tecnecio Tc 99m/farmacocinética , Adulto , Femenino , Humanos , Masculino , Tasa de Depuración Metabólica , Tamaño de la Partícula , Cintigrafía , Radiofármacos/administración & dosificación , Pentetato de Tecnecio Tc 99m/administración & dosificación , Factores de TiempoRESUMEN
The early demonstration of lung involvement in systemic lupus erythematosus (SLE) patients is a difficult but important task. In the present study we attempted to identify abnormalities in pulmonary clearance of 99mTc-DTPA in SLE, correlating their clearance data with clinical findings and disease activity. Forty-six consecutive SLE patients with and without active disease (LACC score) and 30 normal volunteers were studied. All subjects were submitted to pulmonary scintigraphy with 99mTc-DTPA to evaluate the pulmonary clearance, and to a chest X-ray, and SLE patients were submitted to tests of disease activity, spirometry, arterial blood gases and tests to assess acute-phase proteins. Pulmonary clearance was faster in SLE patients with active disease when compared to normal controls [half-life of 67.04 min (51.52-82.55 min) in active SLE versus 85.87 min (78.85-92.87 min) in controls, P<0.05] and there was a higher frequency of abnormal clearance rates in patients with active disease (11 of 26 patients, 42.3%) when compared with SLE patients without disease activity (2 of 20 patients, 10%) (P = 0.04). A significant correlation was observed between the clearance rates and cough (P<0.05), but not between the clearance rates and dyspnea symptoms or radiological findings, duration of SLE disease, antinuclear antibody titers and patterns, C-reactive protein or anti-double stranded DNA antibodies. We conclude that the pulmonary clearance of 99mTc-DTPA is increased in SLE patients with active disease.
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Pulmón/metabolismo , Lupus Eritematoso Sistémico/metabolismo , Pentetato de Tecnecio Tc 99m/farmacocinética , Adolescente , Adulto , Estudios de Casos y Controles , Femenino , Humanos , Masculino , Tasa de Depuración Metabólica , Pruebas de Función RespiratoriaRESUMEN
There are evidences that the biodistribution of radiopharmaceuticals can be modified by some drugs. As chemotherapeutic drugs present important toxic effects, we studied the vincristine effect in the mass of organs and are trying to develop a model to evaluate the action of chemotherapeutic drug using the biodistribution of radiopharmaceuticals. Vincristine was administered (n=15) into female Balb/c mice, the organs isolated and their mass determined. To study the vincristine effect in the biodistribution of technetium-99m-dimercaptosuccinic acid (99mTc-DMSA) or technetium-99m-diethylenetriaminepentaacetic acid (99mTc-DTPA), vincristine (0.03 mg) was administered in the animals (n=15) in three doses. 99mTc-DMSA or 99mTc-DTPA was injected 1h after the last dose. After 0.5h, the animals were sacrificed and the percentage of radioactivity (%ATI) and the percentage of radioactivity per gram of tissue (%ATI/g) in each organ were calculated. The results have shown that the mass decreased significantly (Wilcoxon test, P<0.05) in thymus, spleen, ovary, uterus, kidneys, pancreas. The %ATI to 99mTc-DMSA increased in lung, pancreas, heart, thyroid, brain, and bone, and the %ATI/g increased in uterus, ovary, spleen, thymus, kidney, lung, liver, pancreas, heart, thyroid, brain and bone. To 99mTc-DTPA, the %ATI increased in uterus, ovary, spleen, thymus, kidney, lung, liver, stomach, heart and bone, and the %ATI/g increased in uterus, ovary, spleen, thymus, kidney, lung, liver, stomach, heart and bone. The results were statistically significant (Wilcoxon test). The results can be explained by the metabolization, therapeutic, toxicological or immunosupressive action of the vincristine. This model, probably, should be used to evaluate the toxic effect of various drugs.
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Modelos Biológicos , Tamaño de los Órganos/efectos de los fármacos , Radiofármacos/farmacocinética , Ácido Dimercaptosuccínico de Tecnecio Tc 99m/farmacocinética , Pentetato de Tecnecio Tc 99m/farmacocinética , Vincristina/toxicidad , Animales , Relación Dosis-Respuesta a Droga , Femenino , Ratones , Ratones Endogámicos BALB C , Especificidad de Órganos/efectos de los fármacos , Pruebas de Toxicidad/métodosRESUMEN
Mitomycin C (MMC) has been used as a component of many chemotherapeutic regimens and some toxic effects of this substance have been reported. As it has been reported that the toxicological effect of a drug can alter the biodistribution of radiopharmaceuticals and because patients on chemotherapeutic treatment can be submitted to a nuclear medicine procedure, we investigated whether MMC could affect the uptake of various technetium-99m (99mTc) radiopharmaceuticals used for renal evaluations. The purpose of this study was to suggest a model to evaluate the toxic effect of substances in specific organs. Three doses of MMC (0.45 mg) were administered to mice (N=15). One hour after the last dose, 99mTc radiopharmaceuticals, 99mTc-diethylenetriaminepentaacetic acid (99mTc-DTPA), 99mTc-dimercaptosuccinic acid (99mTc-DMSA) or 99mTc-glucoheptonic acid (99mTc-GHA), with activity of 7.4 MBq, were also administered in the treated group and in the control group (N=15). After another 0.5 h, the animals were sacrificed. The organs were isolated, the 99mTc radiopharmaceutical uptake in the organs quantified in a well counter and the percentages of radioactivity (%ATI) calculated. The results have shown that: (i) with 99mTc-DTPA, the %ATI increased in the pancreas, ovary, uterus, stomach, kidney, spleen, thymus, heart, lung, liver, thyroid and bone; (ii) with 99mTc-DMSA, the %ATI decreased in all the organs except for the brain; and (iii) with 99mTc-GHA, the %ATI increased in the liver and decreased in the stomach, thymus, heart and thyroid. The effects of this chemotherapeutic drug on the biodistribution of these radiopharmaceuticals were statistically significant (Wilcoxon test, p<0.05) and could be explained by the metabolization and/or therapeutic action of MMC. Studies with other radiopharmaceuticals are in progress.
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Riñón/diagnóstico por imagen , Riñón/metabolismo , Mitomicina/toxicidad , Radiofármacos/farmacocinética , Compuestos de Tecnecio/farmacocinética , Animales , Relación Dosis-Respuesta a Droga , Interacciones Farmacológicas , Femenino , Ratones , Ratones Endogámicos BALB C , Especificidad de Órganos/efectos de los fármacos , Cintigrafía , Ácido Dimercaptosuccínico de Tecnecio Tc 99m/farmacocinética , Pentetato de Tecnecio Tc 99m/farmacocinética , Factores de Tiempo , Distribución Tisular/efectos de los fármacosRESUMEN
OBJECTIVE: Vincristine has been widely used in various chemotherapeutic protocols in oncology. The purpose of this study was to evaluate the effect of vincristine on the biodistribution of 99mTc-DMSA, 99mTc-GHA, and 99mTc-DTPA in Balb/c female mice. METHODS: Vincristine (0.03 mg, 0.3 mL) was injected into female isogenic Balb/c mice (n = 15), in 3 doses over an interval of 96 h. The 99mTc-DMSA, 99mTc-GHA, or 99mTc-DTPA (7.4 MBq) was administered after the last dose of vincristine. After 0.5 h the animals were killed rapidly. The organs (pancreas, thyroid, brain, thymus, ovary, uterus, spleen, kidney, heart, stomach, lung, liver, bone, and lymph nodes) were isolated and the radioactivity in each organ was counted in a NaI(Tl) well counter. The percentage of radioactivity (%) in each was calculated and compared with the control group. Statistical analysis was performed by Wilcoxon test (P < 0.05). RESULTS: The percentage of 99mTc-DMSA was increased in the lung, pancreas, heart, thyroid, brain, bone, and lymph nodes (inguinal and mesenteric). The percentage of 99mTc-GHA was decreased in the uterus, ovary, spleen, thymus, lymph nodes (inguinal and mesenteric), kidney, and heart. The percentage of 99mTc-DTPAwas increased in thymus, lymph nodes (inguinal and mesenteric), ovary, uterus, spleen, kidney, heart, stomach, lung, liver, and bone. CONCLUSION: The results could be explained by the metabolization, toxic effect, therapeutic, or immunosupressive action of the studied chemotherapeutic drug.
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Antineoplásicos/farmacología , Compuestos de Organotecnecio/farmacocinética , Radiofármacos/farmacocinética , Azúcares Ácidos/farmacocinética , Ácido Dimercaptosuccínico de Tecnecio Tc 99m/farmacocinética , Pentetato de Tecnecio Tc 99m/farmacocinética , Vincristina/farmacología , Animales , Femenino , Ratones , Ratones Endogámicos BALB C , Distribución TisularRESUMEN
The biodistribution of radiotracers used in diagnostic imaging can be grossly and recognizably altered by a wide variety of drugs and other treatment modalities, such as surgery and radiotherapy. Knowledge of such altered biodistribution is important both in making diagnostic inferences from scans and in dosimetric considerations. Vincristine is a drug that has been used as a component of many chemotherapeutic regimens because of its relative lack of hematologic toxicity. Its mechanism of action is by interfering with microtubule formation. The metabolic fate of vincristine has not been clearly determined and apparently undergoes in vivo decomposition. We have studied the effect of vincristine on the biodistribution of the 99mTc-DTPA. Vincristine was administered by ocular plexus via into female isogenic Balb/c mice. One hour after the last dose, 99mTc-DTPA (7.4 MBq) was injected and after 0.5 hour the animals were rapidly sacrificed. The organs were isolated, the radioactivity uptakes determined in a well counter and the percentages of radioactivity (% rad) in the organs calculated. The results have shown that the percentage rad has not been significantly altered in pancreas, thyroid and brain whilst a significant increased in thymus, ovary, uterus, spleen, kidney, heart, stomach, lung, liver and bone was reported. The results could be explained by the metabolization and/or therapeutic and immunosuppressive action of vincristine.
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Antineoplásicos/farmacología , Radiofármacos/farmacocinética , Pentetato de Tecnecio Tc 99m/farmacocinética , Vincristina/farmacología , Animales , Femenino , Ratones , Ratones Endogámicos BALB C , Distribución Tisular/efectos de los fármacosRESUMEN
The aim of this study was to compare gallium-67 citrate lung imaging with the pulmonary clearance of 99mTc-DTPA (technetium 99m diethylenetriaminepentaacetic acid) in 9 patients with amiodarone pneumonitis (8 males and 1 female, aged 58 to 76 years). The diagnosis of amiodarone pneumonitis was based on clinical and radiological grounds in all patients, and histological changes in seven. The mean values for the effective half-life of the pulmonary clearance of 99mTc-DTPA aerosol were below the normal range in all 9 patients, and lower than the values obtained previously for patients on a long-term amiodarone regimen without side effects. Positive gallium-67 accumulation was demonstrated in 7 of the 9 patients. Two patients had negative gallium-67 imaging and increased alveolar-capillary 99mTc-DTPA clearance; with corticosteroid therapy and discontinuation of amiodarone, their radiological changes and clearance became normal within 120 days. In conclusion, when compared to gallium-67 lung imaging, the 99mTc-DTPA aerosol clearance is more advantageous because it is a much faster test than the gallium scan. This is essential for those patients suspected of amiodarone pneumonitis who need specific therapy as soon as possible. Moreover, the 99mTc-DTPA aerosol clearance test appears to be a more useful diagnostic tool because it is positive even in those patients who have normal gallium-67 lung imaging.
Asunto(s)
Amiodarona/efectos adversos , Radioisótopos de Galio , Neumonía/inducido químicamente , Neumonía/diagnóstico , Pentetato de Tecnecio Tc 99m , Adulto , Aerosoles , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Masculino , Tasa de Depuración Metabólica , Persona de Mediana Edad , Neumonía/metabolismo , Pentetato de Tecnecio Tc 99m/farmacocinéticaRESUMEN
Age is known to reduce the efficacy of body organs and systems, even in the absence of disease. The alveolar-capillary clearance (ACC) rate is representative of the alveolar-capillary barrier's functional state. We studied 29 healthy non-smokers, who were selected after clinical and radiographic evaluation. The patients were divided into three groups based on age: Group I, < or = 30 years (n = 10); Group II, 31-55 years (n = 9); Group III, > or = 56 years (n = 10). Each patient inhaled 750 MBq 99Tcm-diethylenetriamine pentaacetate (99Tcm-DTPA) aerosol generated by a Venticis nebulizer (particles with a mean diameter of 1.1 microns) for 5 min. Forty frames of 30 s duration each were acquired and the ACC rates for the right and left lungs determined using a computer program. The mean ACC rates for the three groups were as follows: Group I, 1.31% min-1; Group II, 1.08% min-1; Group III, 0.76% min-1. The differences between Groups I and III (P < 0.001) and Groups II and III (P = 0.03) were shown to be significant. There was no significant difference between Groups I and II. Possible explanations for an age-related reduction in ACC rates include a reduction in the internal alveolar surface, the closure of the small airways, a reduction in the lung blood capillaries and a reduction in cardiac output. We conclude that there appears to be an age-related reduction in ACC rates in healthy non-smokers, even in the absence of clinically and radiographically detectable lung disease. However, larger studies are required.
Asunto(s)
Envejecimiento/fisiología , Pulmón/diagnóstico por imagen , Alveolos Pulmonares/fisiología , Pentetato de Tecnecio Tc 99m/farmacocinética , Administración por Inhalación , Adulto , Anciano , Capilares , Femenino , Humanos , Pulmón/crecimiento & desarrollo , Pulmón/fisiología , Masculino , Tasa de Depuración Metabólica , Persona de Mediana Edad , Nebulizadores y Vaporizadores , Alveolos Pulmonares/irrigación sanguínea , Alveolos Pulmonares/diagnóstico por imagen , Cintigrafía , Valores de Referencia , Pentetato de Tecnecio Tc 99m/administración & dosificaciónRESUMEN
BACKGROUND: Nuclear medicine uses computerized scintillation cameras for scan processing. For the radio-renogram, the main objective is to observe the passage of radionuclides through the kidneys during a given time. The new software automatically provides data of the dynamic studies, but there is one step (the drawing of regions of interest, ROI) handled by an operator. With the ROI drawings the computer integrates their radioactivity and displays it as time/activity curves, and calculates the Tmax (time to achieve maximal activity) and the T1/2 (time to eliminate half of the Tmax) of each kidney. OBJECTIVE: To evaluate inter-observer variability in drawing the ROI on renal scans. MATERIAL AND METHODS: Four observers with at least seven years of experience in the procedure drew independently the ROI of 38 renograms of 20 patients (two transplants) to obtain the Tmax and T1/2. The interobserver CV was calculated for the Tmax and the T1/2 of the 38 scans. RESULTS: Globally the interobserver variability was larger for T1/2 than for Tmax. There were four scans with small differences in Tmax and/or T1/2 but which lead to inter-observer discrepancies in the classification (normal/abnormal). The partition of the scans in three groups (1 = Tmax and T1/2 normal; 2 = only Tmax normal; 3 = both abnormal) showed significant intergroup differences in the interobserver variability (Kruskal-Wallis p = 0.032) which were caused by the larger variability in group 2 (6 of 11 scans with CV > 4%) than in the other groups (none with CV > 4%). CONCLUSIONS: 1. The interobserver discrepancies in classification were observed only in cases with parameters slightly abnormal (8-9 min in Tmax, 15-20 min in T1/2). 2. We have no explanation for the larger interobserver variability of the Tmax in group 2 study of intraobserver variability in these same four observers may help in gaining insight to some of the observations in this study.
Asunto(s)
Interpretación de Imagen Asistida por Computador , Pruebas de Función Renal , Riñón/diagnóstico por imagen , Variaciones Dependientes del Observador , Pentetato de Tecnecio Tc 99m/farmacocinética , Gráficos por Computador , Cámaras gamma , Semivida , Humanos , Sistemas Hombre-Máquina , CintigrafíaRESUMEN
1. The radioaerosol 99mTc-DTPA produced by jet and ultrasonic nebulizers was characterized by measuring the median mass diameter (MMD) and geometric standard deviation (sigma g) and these characteristics were interpreted in terms of the aerodynamic principles of inertial impactation. 2. Jet nebulizers of the same model, with different outflows (NSA = 0.14 ml/min; NSB = 0.24 ml/min and NSC = 0.40 ml/min) showed different radioaerosol mass distribution, with MMD (NSC) > MMD (NSA). The ultrasonic nebulizer US-1000 from Narcosul, which is operated with an air flow of 2 l/min and frequency of 1.6 MHz, generated radioaerosol with MMD = 2.40 microns, higher than that obtained with most of the jet nebulizers evaluated (NSA = 1.50 microns; NSB1V = 1.40 microns; NSB2V = 1.20 microns and PITT#1 - 0.80 microns), and the ultrasonic nebulizer presented the highest outflow of the nebulized solution (1.15 ml/min). 3. Connecting one or two impactation reservoirs to the NSB jet nebulizer modified the mass distribution, which became significantly narrower for NSB2V when compared to the other two nebulizers. NSB2V presented a mass percentage with a diameter of 3 microns or less and a sufficient outflow for use in ventilation and pulmonary permeability studies. 4. Comparison of the mass collected in the cascade impactor and the total mass generated by the NSB, NSB1V and NSB2V nebulizers showed, on average, 4.5% efficiency in radioaerosol generation with a diameter of less than 16 microns and 3.2% efficiency for a diameter of 3 microns or less.
Asunto(s)
Nebulizadores y Vaporizadores , Pentetato de Tecnecio Tc 99m/análisis , Aerosoles , Cromatografía Líquida de Alta Presión , Diseño de Equipo , Pentetato de Tecnecio Tc 99m/farmacocinéticaRESUMEN
BACKGROUND: Increased pulmonary epithelial permeability evaluated by the rate of clearance from lung to blood of the radioaerosol solute technetium-99m labelled diethylenetriamine pentaacetate (99mTc-DTPA) has been reported in smokers and in workers exposed to silica dust. A study was carried out to determine whether there are additive effects of cigarette smoke and exposure to silica dust on clearance rates of 99mTc-DTPA in ceramic workers. METHODS: Thirty one subjects with silicosis were studied, of whom 18 smoked cigarettes and 13 were non-smokers. They had similar histories of exposure to silica dust, and radiological alterations consistent with silicosis. The results from these patients were compared with those from normal subjects and smokers previously studied by the authors. RESULTS: Pulmonary function values were normal in most patients and not significantly different among groups. The median (range) rate of clearance of 99mTc-DTPA in smokers with silicosis was 4.1 (1.9-12.7) %/minute, which was higher than the rates in non-smoking patients with silicosis of 2.2 (1.1-6.6) %/minute and in smokers without exposure to silica dust of 2.9 (1.6-4.5) %/minute. These differences were more evident and significant when the clearance rates of the lower lobes of the three groups were compared. Clearance rates higher than 3%/minute were much more frequent in smokers with silicosis (85%) than in non-smoking patients with silicosis (15%) and in smokers (40%). CONCLUSION: In ceramic workers with radiographic changes resulting from exposure to silica dust, there is an additive effect of inhalation of silica dust and cigarette smoking on clearance rates of 99mTc-DTPA.
Asunto(s)
Polvo/efectos adversos , Pulmón/metabolismo , Exposición Profesional/efectos adversos , Dióxido de Silicio/efectos adversos , Fumar/efectos adversos , Adulto , Epitelio/metabolismo , Humanos , Permeabilidad , Fumar/metabolismo , Pentetato de Tecnecio Tc 99m/farmacocinéticaRESUMEN
Tc-99m isonitrile uptake in a metastatic brain tumor is demonstrated using planar and SPECT imaging. Comparison with Tc-99m DTPA shows a different distribution pattern and uptake intensity, suggesting a different mechanism for both tracers. It is possible that Tc-99m CPI could reflect metabolic activity of the tumor cells and might be useful to evaluate the grade of malignancy as well as the recurrence of brain tumors.