Exploring Physical Activity Levels in Patients with Cardiovascular Disease-A Preliminary Study.

Increased physical activity may prevent disease onset and severity in individuals with cardiovascular disease. However, studies evaluating physical activity in people with cardiovascular disease are limited. This prospective observational study aimed to objectively assess the level of physical activity in patients with cardiovascular disease and determine the actual extent of physical activity in their daily lives. Participants aged 20 years or older with cardiovascular disease at a cardiology clinic were included. Physical activity was measured using an activity meter with a three-axis acceleration sensor. Overall, 58 patients were included in the study. Household activities were found to be more frequent sources of physical activity. The step count was related to age and housework, while total physical activity and household activity were related to age and work. Locomotive activity was related to sex and housework. Total physical and household activities tended to decrease with age. These findings indicate the influence of work and household chores on physical activity and suggest that physical activity may be underestimated if household activity is not also assessed. These fundamental findings may provide clinical evidence to underpin physical activity for patients with cardiovascular disease.

Determination of activity meter settings for the PET nuclides 44Sc and 89Zr.

Radionuclide activity meters depend on "calibration setting numbers" that are specific for a certain combination of radionuclide, volume and geometry. This work describes their determination for two PET emerging nuclides (44Sc and 89Zr), three commercial activity meters (CAPINTEC CRC15 BETA, ATOMLAB BIODEX 500 and VEENSTRA VDC 405) and two geometries: 1 mL plastic syringes and 5 mL glass vials. For 44Sc, only values for the dial setting for 5 mL ampoules were reported previously and its use for the assayed geometries would lead to significant differences. For 89Zr more data were available in the literature, and results are provided for new geometries. All results rely on the absolute standardisation in activity of solutions of both radionuclides.

The concept of minimum detectable activity of radionuclide activity meters and their suitability for routine quality control of radiopharmaceuticals. An experimental study.

Radionuclide activity meters ("dose calibrators") are ionization chambers designed to measure relatively high amount of activities which are normally contained in radiopharmaceuticals. However, in the current radiopharmacy practice, these radiation detectors have been proposed to be used in measurements of samples with lower activity, such as in routine quality control (QC) tests. To check the feasibility of such measurements, in this work we assessed the performance of four different devices in the lower range of detectability, by means of experimental measurements of a radioactive sample. Accuracy and precision of each device was evaluated as a function of the activity contained in the sample in order to estimate a threshold value, or minimum detectable activity (MDA), which, according to our operational definition, may be used to express the concept of Limit of Quantification (LoQ). Moreover, a generalized procedure for the estimation of the MDA was established, which, being device- and radionuclide-independent, it may be adopted by every laboratory. Our results showed a significant variability in the MDA achieved by different activity meters. Hence a single QC test may result feasible with one specific instrument, and not with another one. Moreover, feasibility depends also on the confidence level required for each test. For these reasons, each activity meter should be qualified for its MDA or LoQ by each laboratory according to a procedure such as that described in this paper.

Aseguramiento metrológico en la producción y uso de radiofármacos / Metrological assurance during production and application of radiopharmaceutical

En el trabajo se presentan los principales resultados obtenidos por el Departamento de Metrología de Radionúclidos del Centro de Isótopos, concernientes al establecimiento de patrones de medición de la actividad (becquerel) de los radionúclidos emisores gamma y beta, así como la diseminación de la unidad hasta los usuarios finales. Se resume la participación del Departamento en los últimos 5 años en comparaciones claves y suplementarias del Órgano de Cooperación Euroasiática de Institutos Metrológicos Nacionales, en comparaciones bilaterales realizadas con laboratorios metrológicos de otros países, así como ejercicios de aptitud organizados por el Organismo Internacional de Energía Atómica. Se ofrece información acerca de la importancia del reconocimiento internacional alcanzado de las capacidades de medición y calibración del Departamento mediante su inclusión en el Anexo C de la base datos de comparaciones claves del Buró Internacional de Pesos y Medidas. Se señalan los proyectos actuales que se ejecutan como elementos fundamentales para garantizar el aseguramiento metrológico indispensable a los desarrollos previsibles en la medicina nuclear y la radioterapia con fuentes no encerradas.

The paper presents the main achievements of the Department of Radionuclide Metrology at the Isotope Centre, concerning the establishment of measurement standards of the activity (Bq) of gamma and beta emitting radionuclides, as well as the dissemination of the unit to end users. It highlights the participation of the department in the last five years in key and supplementary comparisons organized in the frame of the regional Euro-Asian Cooperation of National Metrological Institutes and bilateral inter-laboratory comparisons, as well as in proficiency tests organized by International Atomic Energy Agency. It provides information about the importance of international recognition achieved, and the calibration and measurement capabilities of the department through its inclusion in Annex C of the database of key comparisons of the International Bureau of Weights and Measures. Current projects that are being implemented as basic elements for metrological assurance essential to foreseeable developments in nuclear medicine and radiation therapy with unsealed sources are identified.