RESUMO
BACKGROUND: Although standard operational procedures for pre-therapeutic dosimetry already exist for the determination of the maximum safe activity to treat differentiated thyroid cancer patients, empiric activity administration of 131I is still the most frequent way of treatment. In this way, the absorbed dose to the blood/bone marrow remains unknown. PURPOSE: In this work, we present a strategy to estimate radiation dose to the blood in an outpatient setting. METHODS: A mobile application was developed, which together with an off-the-shelf compact semiconductor radiation detector allows the determination of whole-body time-integrated activity coefficients. The methodology was tested in a cohort of 79 differentiated cancer patients who received therapeutic 131I activities. Post-therapeutic whole-body time-integrated activity coefficients were compared against pre-therapeutic estimates in a subset of 13 patients. RESULTS: The 95% limits of agreement between pre whole-body and post whole-body time integrated activity coefficients were [-14.4; 6.6] h when considering outliers and [-6.2; 3.6] h without outliers. A high dispersion in blood dose coefficients was found, with a four-fold difference between the highest and lower values. Blood doses were significantly higher for patients treated with dosimetrically guided activities than for empirical activities (median dose = 118 vs. 49 cGy, respectively). Blood dose coefficients were significantly lower for patients prepared with recombinant human thyroid stimulating hormone (rhTSH) than for patients prepared with thyroid hormone withdrawal. A low correlation between blood dose and administered activity was found in empirically treated patients (R2 = 0.26). CONCLUSIONS: We successfully implemented a post-therapeutic internal dosimetry methodology for differentiated thyroid cancer therapy with 131I, which allows to estimate dose to the blood from outpatient measurements with mobile devices. The proposed methodology avoids the need of daily visits to the nuclear medicine department, thus reducing the burden for the patient and for the staff.
Assuntos
Radioisótopos do Iodo , Pacientes Ambulatoriais , Neoplasias da Glândula Tireoide , Humanos , Radioisótopos do Iodo/uso terapêutico , Neoplasias da Glândula Tireoide/radioterapia , Neoplasias da Glândula Tireoide/sangue , Doses de Radiação , Masculino , Radiometria , Feminino , Pessoa de Meia-Idade , Adulto , Aplicativos Móveis , Dosagem Radioterapêutica , IdosoRESUMO
Antecedentes: numerosos estudios han analizado la capacidad antioxidante de los arándanos. Considerando la citotoxicidad de las radiaciones ionizantes, mediada por radicales libres, es imperativo el análisis de fitocompuestos con efecto mitigante potencial. Objetivo: evaluar las propiedades radio-protectoras de de los arándanos, en relación con el daño genético inducido por rayos X. Materiales y métodos: el diseño experimental tuvo dos etapas: primero se ejecutó ensayo in vitro con diez muestras de sangre periférica de mujeres jóvenes no fumadoras. Cada muestra fue analizada mediante Ensayo Cometa en el siguiente grupo de tratamientos: control negativo, tratamiento con arándanos (0,232 mG/mL), irradiación con 4 Gy y tratamiento simultáneo arándanos/irradiación. Se contabilizaron 800 células/individuo, 200 por tratamiento, considerando su repetición. Posteriormente, se realizó ensayo in vivo con sangre periférica de dos mujeres, de condiciones similares a las anteriores, sometidas al consumo de extracto seco de arándanos durante 15 días consecutivos. El muestreo se realizó antes y después del tratamiento y se implementó el Cometa analizando 800 células/individuo, correspondientes al control negativo e irradiación con 4 Gy. Resultados: en ambas etapas, el tratamiento con arándanos demostró una reducción significativa (p<0,01) del daño genómico referido a las muestras irradiadas. Conclusiones: la suplementación dietaria con arándanos podría disminuir los efectos secundarios de la radioterapia, optimizando la calidad de vida del paciente oncológico.
Introduction: Numerous studies have analyzed the antioxidant capacity of blueberries. Considering the ionizing radiation cytotoxicity mediated by free radicals is imperative phytocompounds analysis with potential mitigating effect. Objective: To evaluate radio-protective properties of this fruit in relation to genetic damage induced by x-rays. Materials and methods: Experimental design had two stages. First an in vitro assay using 10 samples of peripheral blood of young and nonsmokers female. Each sample was analyzed by comet assay in the next set of treatments: negative control, treatment with blueberries (0,232 mG / mL), irradiation 4Gy and simultaneous blueberry/ irradiation treatment. Were counted 800 cells/individual, 200 per treatment, considering its repetition. Subsequently, an in vivo assay with peripheral blood of two women, of similar conditions and subject to the consumption of dried extract of blueberries for 15 consecutive days was performed. Sampling was performed before and after treatment and Comet was implemented by analyzing 800 cells / individual, corresponding to the negative control and irradiation with 4 Gy. Results: In both stages, treatment with blueberries showed a significant reduction (p <0.01) of genomic damage relative to irradiated samples. Conclusions: Dietary supplementation with blueberries may decrease the side effects of radiation therapy, optimizing the quality of life of cancer patients.