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Biomedical subjects

A Calderón

Publications and source records attributed to A Calderón.

31 records · Page 2Linked to original sources
PubMedDate not supplied

[Digital radiocardioangiography as an auxiliary method for the precise localization of zones of myocardial concentration of 99mTc-Sn(II)-pyrophosphate. Preliminary report].

A new method is introduced for the superposition of 99mTc-pyrophosphate (PiF) myocardial images on the isolated images of the radioangiocardiographic dextrophase and levophase, in order to include cardiac anatomical references for the accurate topographic localization of the PiF concentration areas. Results in two different patients are presented. In one of them, the PiF concentration was evident at the inferoseptal, inferoapical and posterolateral regions of the left ventricle. In the other, the PiF concentration was evident at the same areas than in the former plus the inferoanterior region of the right ventricle. Our project is to validate this procedure by correlating its results with those obtained through other clinical methods that detect right ventricular infarction.

Angiocardiography↗
PubMedDate not supplied

[Tomographic densitometry of the human thorax].

We show the first clinical images obtained by a new tomographic system based on the detection of the scattered gamma photons of 99mTc by the chest tissues. These images show satisfactory contrast and tomographic effect on the half-chest near the radioactive source. Both effects tend to decrease on the contralateral half-chest. The images rendered important data in differential diagnosis of perfusion defects evident by lung scintigraphy with macroaggregated albumin labeled with 99mTc. Pulmonary density was normal and homogeneous in a healthy volunteer and also in a patient with pulmonary embolism. It demonstrated a hyperdense pulmonary mass in a patient with tumor of the right lung, which produced a perfusion defect evident in the conventional lung scintiscan, and a shadow in the gamma ray transmission image.

Female↗
PubMedDate not supplied

[Experimental evaluation of a tomographic system of the thorax by detection of the dispersion of technetium-99m radiation].

Based on a previous theoretical study, a simple device for the acquisition of bidimensional tomographic images of the human chest densitometry was designed. A radioactive linear source (99mTc) was adapted to the lateral aspect of a gamma camera detector in order to register only those photons scattered at 90 degrees. Resulting images from a liver phantom stuffed with saw dust, showed an evident tomographic effect and a satisfactory contrast between the structures sited at less than 20 cm from the source. These effects tend to decrease with distance. The causes of these deficiencies of the system and their possible corrections are discussed.

Evaluation Studies as Topic↗
PubMedDate not supplied

[Formation and migration of radioactive microemboli to the lung during radiovenography].

Two patients with lower extremity thrombophlebitis were studied by radionuclide venography with macroaggregated albumin labelled with 99mTc. Data analysis was performed with a new method. It generated sequential series of imagen (1-2 sec/frame) of the transit of the tracer through leg, thigh, and abdomen, allowing a more precise definition of temporal changes on regional radioactivity. This method rendered the first real evidence of the binding of the tracer to pre-existent venous thrombi, of the dislodgement of these and their gradual fragmentation during their transit to the lungs. The patients had no complaints during or after the study. Lung scanning, performed 24 hours later, showed slight alteration on regional lung perfusion in one case, and none in the other. It is concluded that radioactive microemboli to the lungs is a minor complication of radionuclide venography, which does not justify prevention. This could only nullify the sensitivity of the procedure.

Adult↗