Effectiveness of pelvic lead blanket to reduce the doses to eye lens and hands of interventional cardiologists and assistant nurses.

The aim of the present study is to analyse quantitatively the potential reduction of doses to the eye lens and the hands of an operator and a nurse by the use of a pelvic lead blanket during coronary angiography (CA) and percutaneous transluminal coronary angioplasty (PTCA) procedures. Thermoluminescent dosimeters were used to assess dose levels to the left eye lens and fingers on both hands of both physician and nurses during single procedures performed with or without the lead blanket. The measurements were carried out at one medical centre and include dosimetric data from 100 procedures. Additional measurements including physician's and patient's doses were made on phantoms in the laboratory. In order to determine the reduction potential of the lead blanket, the doses normalized to DAP (Dose-Area Product) corresponding to the same position of dosimeter were compared against each other for both procedure categories (with and without protection). There was no statistically significant decrease observed in physicians' and nurses' eye lens doses, nor in doses normalized to DAP due to the use of the lead pelvic shield in clinic. However, some trend in reducing the eye lens doses by this shield can be observed. Regarding finger doses, the differences are statistically significant but only for physicians. The mean DAP-normalised doses to the eye lens and left and right finger of physicians, in the presence of a ceiling-suspended transparent lead shield, were 2.24e-5 ± 1.41e-5 mSv/µGym2, 2.31e-4 ± 1.21e-4 mSv/µGym2, and 2.60e-5 ± 1.57e-5 mSv/µGym2 for standard procedures performed without the lead blanket, and 1.77e-5 ± 1.17e-5 mSv/µGym2, 1.70e-4 ± 1.01e-4 mSv/µGym2, and 1.86e-5 ± 1.13e-5 mSv/µGym2 for procedures performed with it. A comparison of the results from the laboratory and the clinic shows that they are consistent regarding the eye lens, while for fingers it suggests that the dose reduction properties of the lead shield are related to the physician's work technique and both patient and lead blanket sizes or its positioning. The highest degree of reduction is observed for cranial and caudal projections together with the use of a patient-adjustable lead blanket; about a 2-fold decrease in finger doses is expected for optimum conditions. However, the laboratory measurements suggest that the use of lead blanket might slightly increase the patient dose, but only when specific projections are constantly used. This limitation should be considered by cardiologists during clinical work if this protection is used. In the light of the presented results, the ceiling-suspended transparent lead shield and the lead glasses seem to be the preferred way to reduce the doses to the eye lens, compared to the lead blanket.

Fourier-plane windowing in the binary joint transform correlator for multiple target detection.

With recent advances in state-of-the-art spatial light modulators, the optical joint transform correlator (JTC) and the binary joint transform correlator (BJTC) are becoming practical signal-processing tools. The performance of these devices is limited by the difficulty of separating the cross correlation between the reference and the targets in the scene from signals resulting from cross correlations between objects in the target scene. One technique that reduces this problem is to use a sliding window in the Fourier plane as a convolution mask filter to set an adaptive binarization threshold. This suppresses the autocorrelation response and reduces the dynamic range of the Fourier-plane signal. This results in correlation performance improvement by a factor of 2 to 4. A mathematical model is developed to describe the windowing process for both the JTC and BJTC for the case in which the scene contains multiple targets and background clutter. The derivation of the windowing process is general and includes any spatial high-pass or bandpass filtering in the Fourier plane. The results are supported with experimental data.

Realizing optical logic with a smart-pixel spatial light modulator.

A method of implementing optical logic has been realized experimentally with a novel liquid crystal on silicon spatial light modulator with an integrated lens arrays. The device allows for three optical inputs and one optical output per pixel. The different logic functions realized, OR, and, nor, nand, and xor, are discussed.

[The significance of scintigraphic, echocardiographic and electrocardiographic left atrial transesophageal pacing in diagnosis of ischemic heart disease]. / Znaczenie scyntygraficznego, echokardiograficznego i elektrokardiograficznego testu stymulacji przezprzelykowej lewego przedsionka w diagnostyce choroby niedokrwiennej serca.

UNLABELLED: The aim of the study was to compare the perfusion scintigraphy (using SPECT method with Tc-99-MIBI) during left atrial transoesophageal pacing test (LAPT) with pacing electrocardiography (ECG), echocardiography (ECHO) and electrocardiography exercise test (ExT) in ischaemic heart disease (IHD) diagnostics. The effect of LATP on heart haemodynamic parameters and the correlation between scintigraphic, echocardiographic and electrocardiographic parameters during LAPT test have been also assessed. Investigations were carried out in 55 subjects (Group I: 36 patients with effort angina pectoris; group II: controls: 19 clinically healthy subjects). Coronarography was performed in 24 patients 6 weeks before or after examinations. LATP test was analyzed with ECG, ECHO and SPECT. Echocardiography did not increase significantly the LATP test diagnostic value. Perfusion scintigraphy enhanced sensitivity and predictive excluding value LATP test. These values were 93.3% v 62.9% and 90% v 59.3% respectively. LATP test assessed with ECG, ECHO and perfusion scintigraphy expressed significantly higher sensitivity and predicting excluding value in comparison to ExT. LATP test analyzed in such way was characterized by 100% sensitivity and 100% predicting excluding value. CONCLUSION: Combination of LATP with electrocardiography, echocardiography and SPECT is a non-invasive high quality method for ischaemic heart disease diagnostics.