A 3D point-kernel multiple scatter model for parallel-beam SPECT based on a gamma-ray buildup factor.

A three-dimensional (3D) point-kernel multiple scatter model for point spread function (PSF) determination in parallel-beam single-photon emission computed tomography (SPECT), based on a dose gamma-ray buildup factor, is proposed. This model embraces nonuniform attenuation in a voxelized object of imaging (patient body) and multiple scattering that is treated as in the point-kernel integration gamma-ray shielding problems. First-order Compton scattering is done by means of the Klein-Nishina formula, but the multiple scattering is accounted for by making use of a dose buildup factor.

Generation of dose-volume histograms using Monte Carlo simulations on a multicellular model in radionuclide therapy.

An accurate calculation of the absorbed dose at the cellular level can lead to the optimization of the administered activity and the best clinical response in radionuclide therapy. This paper describes the implementation of dose-volume histograms (DVHs) for dosimetry at the cellular level in radionuclide therapy. The FOTELP code, based on Monte Carlo simulations of photon and electron transport, was used on a three-dimensional multicellular tumor model, which includes tumor morphometry and cell-labeling parameters.

[Myocardial perfusion scintigraphy in identification and localization of individual coronary lesions].

The aim of this study was to evaluate the accuracy of myocardial perfusion scintigraphy with technetium-99m tetrofosmin by single-photon emission computed tomography (SPECT), using one-day protocol in the identification and localization of individual stenosed coronary vessels. Sixty-eight patients with suspected coronary artery disease (CAD) were studied. In thirty of them coronary angiography showed significant stenosis (> or = 50%).

[Systemic manifestations of idiopathic inflammatory myopathies--part two].

The aim of the investigation was to establish if the finding of immunoserologic and pathohistologic parameters of the altered humoral immune response in patients with dermatopolymyositis was associated with the occurrence of more severe clinical patterns of the diseases followed by general symptoms and the affection of visceral organs. Sensitivity, specificity, accuracy, positive and negative prediction of immunologic parameters of the disease were determined compared to the occurrence of certain systemic manifestations of the disease. Significant (80-100%) correlation of systemic manifestations with the altered immunoserologic and histopathologic parameters of the disease was confirmed, so that it could be assumed that pathologic humoral response had a significant role in the onset of systemic manifestations during dermatopolymyositis.

[Stress-rest myocardial tomoscintigraphy with 99mTc-tetrofosmin in the diagnosis of ischemic disease].

The aim of this study was to evaluate the accuracy of 1-day stress-rest technetium-99m tetrofosmin myocardial tomography in the identification of patients with coronary artery disease (CAD), and in the detection of the individual occluded coronary vessels. A total of 42 patients with suspected CAD were studied. Significant coronary narrowing (> or = 50% luminal stenosis) was detected by angiography in 22 patients.

[Systemic manifestations of idiopathic inflammatory myopathies--part one].

Dermatomyositis and polymyositis are the idiopathic inflammatory myopathies of autoimmune origin. Apart from muscle weakness, general symptoms such as the affection of visceral organs and altered indicators of humeral immunity occur in a minority of patients. The aim of the study was to establish whether the systemic manifestations of the disease, altered immunoserologic parameters and findings of muscle vasculitis occurred more frequently in patients with dermatomyositis or polymyositis.

[Evaluation of perfusion of transplanted microvascular flaps using radionuclide arteriography].

Microvascular flap by its autonomous circulation, following the transplantation in recipient region, provides the quantity of blood sufficient for nutritive needs of flap, but it also provides additional blood supply in the surrounding of recipient region. The evaluation of the relation of the tissues perfusion of transferred microvascular flaps and the tissues of surrounding recipient region was done in 33 patients, 15.24 months after the transplantation of microvascular flaps, by radionuclide angiography using Tc-99m in the form of MAA HAS or pertechnetate at the Clinic for Plastic Surgery and Burns of Military Medical Academy (MMA) and at the Institute for Nuclear Medicine of MMA.

[Experimental study of the pathogenesis of frostbite. Part II. Role of the sympathetic-adrenergic system in tissue reperfusion immediately after thawing].

The authors have investigated the role of sympathetic-adrenergic system in reperfusion of muscular tissue of the feet of Wistar rats immediately after thawing using alpha adrenergic blocker phentolamine methanesulfonate (Regitin). Cryoinjury was applied over an experimental model of local, controlled freezing of different intensity for certain experimental groups. Blood flow through microcirculation was measured by scintigraphy, following Tc-99m-pertechnetate clearance that was given in muscular mass of frozen right, as well as unfrozen left feet of rats.

[Etiologic factors which affect the development of infrabony periodontal defects].

The aim of the study was to examine frequency and distribution of etiologic factors which, associated with chronic inflammation, can influence the forming of intrabony periodontal defects. The following were studied: occlusal trauma, erosions and concrements on the roots, tooth malposition, the absence of contact point, inadequate interproximal distance of roots and iatrogenic factors. The results revealed that the most frequent etiologic factor in the forming of intrabony periodontal defects was occlusal trauma--55.

Assessment of osteogenic potential of the natural origin bioceramics implanted into the human infrabony periodontal defects.

The osteogenic potential of natural origin bioceramics implanted in human periodontal infrabony defects was investigated Histologic and electron-microscopic analyses of implants 3 and 4.5 months after implantation were used for the estimation of osteogenic potential. Results show that the bioceramics of natural origin with a microstructure and canalicular system of the natural bone has a strong osteogenic potential.

[Mechanisms of the favorable effect of spinal anesthesia in traumatic shock].

Changes in the level of total peptidoleukotriens-pLT (LTC4 + LTD4 + LTE4) and inositol triphosphates (IP3) were analyzed in the thalamus of rats subjected to "tourniquet" trauma of both hind extremities (LD50) depending on the power of afferent nociceptive nerve impulses. Prevention of spreading, i.e.

Evaluation of left ventricular diastolic function by radionuclide ventriculography in patients with coronary artery disease.

Radionuclide ventriculography (RNV) was used to assess the peak filling rate (PFR) in 20 patients with coronary artery disease (CAD). Dipyridamole RNV was used in 5 normal subjects and 10 patients with CAD with the view to evaluating PFR increase. Significant difference in PFR values was established between normal subjects and CAD patients.

[Use of 99mTc-pyrophosphate and coronarography in the diagnosis of simultaneous myocardial infarct of the right and left cardiac ventricles].

Myocardial scintigraphy was performed using 99m-Tc-pyrophosphate in 50 patients with suspected coexisting right ventricular and left inferior ventricular heart infarction and in 50 patients with left inferior ventricular infraction only. In all survived patients additional selective coronarography was performed and in all died patients autopsy was performed. The aim of the study was to evaluate reliability of myocardial scintigraphy using 99m-Tc-pyrophosphate in the diagnosis of coexisting infarction of both heart ventricles.

Evaluation of diagnostic reliability of radionuclide phlebography using 99mTc-MAA to detect deep venous thrombosis; its role in establishing indications for inferior vena cava filter implantation.

Radionuclide phlebography (RNP) of the lower extremities and pelvis was performed using 99mTc-MAA in 40 patients with pulmonary thromboembolism. Deep venous thrombosis (DVT) was found in all patients, more frequently in the right calf and in the left iliac veins in 20 patients (55%). RNP and contrast phlebography (CP) were performed in 18 patients and confirmed the presence of DVT in all cases.

[Rational treatment of oral and dental diseases in war].

The treatment of oral and dental diseases during the war is complicated with many aggravating circumstances, such as: a great number of ill and injured persons per dental team; limited handling of all kinds of material, lack of time, etc. The paper deals with the epidemiological research of the most frequent oral diseases in soldiers of the Yugoslav Army. The need for dental care was established upon these data.