Quantitative analysis of lung parenchymal involvement in Behçet's disease by the novel automatic program.

OBJECTIVES: We aimed to quantitatively analyze lung parenchymal changes in Behçet's patients and to detect early parenchymal quantitative changes that occur in the absence of positive visual radiological findings. METHODS: In our study, a total of 31 patients with Behçet's disease, 17 with positive radiological findings and 14 patients without positive radiological findings, and a control group of 33 individuals were evaluated. The automatic program determined lung volumes, lung densities, and opacity volume percentages by evaluating the contrast-enhanced lung computed tomography scans. RESULTS: The total lung volume was 3632.98 ± 1100.53 mL in the Behçet's disease patient group and 4925.70 ± 1098.88 mL in the control group, and there was a significant decrease in the total lung volume in Behçet's disease patients (P < 0.0001). The mean lung density was -723.73 ± 65.16 in the Behçet's disease patient group and -767.35 ± 41.17 in the control group, and there was a significant increase in the mean density in the Behçet's patients (P = 0.0023). A significantly higher correlation was observed between lung density and lung volume in Behçet's patients (P < 0.0001, r = -0.795). The lung volume of Behçet's disease patients with negative radiological findings was significantly lower than that of the control group (P = 0.0342). CONCLUSIONS: Lung volumetric changes in Behçet's disease patients are the quantitative data most affected by the disease. In addition, lung volume decreases in Behçet's patients who do not have visual parenchymal involvement.

Neural network predictions of (n,2n) reaction cross-sections at 14.6 MeV incident neutron energy.

In this study, we have estimated the (n,2n) reaction cross-section for 14.6 MeV incident neutron energy by using the artificial neural network (ANN) method. We have also predicted the reaction cross-sections whose experimental data are not available in the literature. For the construction of the present ANN, available experimental data in the literature has been borrowed. The ANN estimations have been compared with the available experimental data and the results from a theoretical calculation and the two commonly used computer codes. According to the results that the ANN results are in good agreement with the experimental data than the codes and this shows that the method can be a powerful tool for the estimation of cross-section data for the neutron-induced reactions. Considering the predictions of the ANN of the cross-sections whose experimental data are not available in the literature, it is seen that they are in line with the trend of the experimental data, but far from the results given by the theoretical calculations and two computer codes.

A computer program for calculation of approximate embryo/fetus radiation dose in nuclear medicine applications.

OBJECTIVE: In this study, we aimed to make a computer program that calculates approximate radiation dose received by embryo/fetus in nuclear medicine applications. MATERIAL AND METHODS: Radiation dose values per MBq-1 received by embryo/fetus in nuclear medicine applications were gathered from literature for various stages of pregnancy. These values were embedded in the computer code, which was written in Fortran 90 program language. RESULTS: The computer program called nmfdose covers almost all radiopharmaceuticals used in nuclear medicine applications. Approximate radiation dose received by embryo/fetus can be calculated easily at a few steps using this computer program. CONCLUSION: Although there are some constraints on using the program for some special cases, nmfdose is useful and it provides practical solution for calculation of approximate dose to embryo/fetus in nuclear medicine applications. CONFLICT OF INTEREST: None declared.

Radiation dose to technologists per nuclear medicine examination and estimation of annual dose.

UNLABELLED: Conventional diagnostic nuclear medicine applications have been continuously increasing in most nuclear medicine departments in Turkey, but to our knowledge no one has studied the doses to technologists who perform nuclear medicine procedures. Most nuclear medicine laboratories do not have separate control rooms for technologists, who are quite close to the patient during data acquisition. Technologists must therefore stay behind lead shields while performing their task if they are to reduce the radiation dose received. The aim of this study was to determine external radiation doses to technologists during nuclear medicine procedures with and without a lead shield. Another aim was to investigate the occupational annual external radiation doses to Turkish technologists. METHODS: This study used a Geiger-Müller detector to measure dose rates to technologists at various distances from patients (0.25, 0.50, 1, and 2 m and behind a lead shield) and determined the average time spent by technologists at these distances. Deep-dose equivalents to technologists were obtained. The following conventional nuclear medicine procedures were considered: thyroid scintigraphy performed using (99m)Tc pertechnetate, whole-body bone scanning performed using (99m)Tc-methylene diphosphonate, myocardial perfusion scanning performed using (99m)Tc-methoxyisobutyl isonitrile, and (201)Tl (thallous chloride) and renal scanning performed using (99m)Tc-dimercaptosuccinic acid. RESULTS: The measured deep-dose equivalent to technologists per procedure was within the range of 0.13 ± 0.05 to 0.43 ± 0.17 µSv using a lead shield and 0.21 ± 0.07 to 1.01 ± 0.46 µSv without a lead shield. Also, the annual individual dose to a technologist performing only a particular scintigraphic procedure throughout a year was estimated. CONCLUSION: For a total of 95 clinical cases (71 patients), effective external radiation doses to technologists were found to be within the permissible levels. This study showed that a 2-mm lead shield markedly reduced the external dose to technologists. The doses to technologists varied significantly for different diagnostic applications. Consequently, the estimated annual dose to a technologist performing only a particular scintigraphic procedure is very different from one type of procedure to another. The results of this study should help in determining the rotation time of technologists in different procedures and differences in their individual techniques.