RESUMO
A method for the detection of the P and T waves, as well as the identification of their onset and offset boundaries in an ECG, is described in this paper. This method is based on a recently proposed "length" transformation, which exhibits some very interesting characteristics and can be utilized for one-channel or multichannel waveforms. The utilization of this transformation for the detection of the P and T waves in ECGs is exemplified in this paper. Experimental results are also given with real ECGs taken from the standard CSE ECG library.
Assuntos
Eletrocardiografia/métodos , Processamento de Sinais Assistido por Computador , Algoritmos , Computação MatemáticaRESUMO
We estimate the absorbed dose to the bladder walls, Db, due to [99mTc]pertechnetate direct radionuclide cystography, with due consideration to the dynamic nature of the examination. Our analytical method resulted in Db values expressed as functions of the bladder filling time. These values are compared with published data based on a static bladder model. It is shown that the Db value depends strongly on the protocol under which the examination is carried out. It is also shown that the normal saline flow rate and the time of the administration of the radioactive material can be adjusted so that the radiation burden may be greatly reduced.
Assuntos
Doses de Radiação , Tecnécio , Doenças da Bexiga Urinária/diagnóstico por imagem , Bexiga Urinária , Adulto , Criança , Feminino , Humanos , Masculino , Matemática , Modelos Biológicos , Ovário , Cintilografia , Pertecnetato Tc 99m de Sódio , TestículoRESUMO
The parameters of 51Cr labelled red cell survival curves were calculated in 33 patients with homozygous beta-thalassaemia, 8 with sickle-cell anaemia and 3 with s -- beta-thalassaemia, using a non-linear weighted least squares analysis computer program. In thalassaemic children the calculated parameters denote that the shortening of the mean cell life is due to early senescence alone, while there is some evidence that in thalassemic adults additional extracellular destruction mechanisms participate as well. Red cell survival curves from patients with sickle-cell anaemia and s -- beta-thalassaemia resemble each other, while their parameters indicate an initial rapid loss of radioactivity, early senescence and the presence of extracellular red cell destruction factors.
