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The size-specific dose estimate (SSDE) is a metric for an estimation of patient dose in computed tomography (CT). The SSDE strongly depends on the water-equivalent diameter (DW). In abdominal CT examinations, a contrast agent is sometimes used to more clearly visualize tissue lesions. The Hounsfield unit (HU) of CT images with and without the use of a contrast agent at specific areas is slightly different and it may affect the DW value. This study aimed to compare the DW values calculated from axial CT images in patients who had undergone routine abdominal scans both with and without the use of a contrast agent. Axial images of 144 patients with a weight range of 3.5 kg to 90 kg who had undergone routine abdominal scans both with and without the use of a contrast agent using a Siemens Sensation 64 CT scanner were retrospectively collected. The DW values were automatically calculated using the Matlab-based IndoseCT (version 15a) software. The results show the percentage difference between DW,contrast and DW,non-contrast is below 2 %.As a result, the mean SSDEcontrast is 1.5 % smaller than SSDEnon-contrast. Due to the effect of a contrast agent on the DW and SSDE values is below 2 %, the axial images of CT abdomen without the use of a contrast agent can be used as the accurate estimation of DW and SSDE for images with the use of a contrast agent.

Molekul DNA menunjukkan polarisasi yang kuat sehingga memungkinkan baik gerak elektroforesis berdasarkan muatan negatifnya maupun gerak dielektroforesis berdasarkan induksi polarisasi. Perancangan alat menggunakan kombinasi prinsip elektroforesis dan dielektroforesis dilengkapi perangkat lunak untuk mengukur konsentrasinya sangat diperlukan. Utamanya mengingat uji kualitatif DNA berbasis visualisasi pada gel elektroforesis bersifat sangat subyektif dan kurang terukur. Pengukuran konsentrasi DNA menggunakan spektrofotometer UV/VIS sangat tergantung oleh ketersediaannya di laboratorium. Penelitian bertujuan untuk mendesain piranti untuk mengukur konsentrasi DNA berdasarkan visualisasinya pada gel elektroforesis menggunakan perangkat lunak berbasis MatLab. Pengukuran konsentrasi DNA didasarkan visualisasinya pada gel elektroforesis lalu dibandingkan dengan hasil penghitungan spektrofotometer UV/VIS. Hasil penelitian menggunakan piranti tersebut memperlihatkan visualisasi DNA yang lebih optimal. Hasil pengukuran jumlah DNA menggunakan spektrofotometer memiliki kecenderungan yang sama dengan hasil pengukuran menggunakan perangkat lunak berbasis MatLab meskipun terdapat perbedaan nilai kuantitatif.ABSTRACTMolecules of deoxyribo nucleic acid (DNA) show a strong polarization allowing for both motions of the dielectrophoresis induced by polarization and electrophoresis based on its negative charge. Considering high subjective and less quantifiable result of the visualization based qualitative test of DNA on gel electrophoresis, designing the tool using a combination of the principles of electrophoresis and dielectrophoresis completed with a software for optimization of DNA visualization and to measure the concentration of small and large–sized DNA fragment is very needed. Accuracy of measurement of DNA concentration using a spectrophotometer UV /VIS is depend on its availability in the laboratory. The aim of this study was to design device for optimization of DNA visualization and measuring the concentration in the gel electrophoresis using MatLab- based software. Experiment using this software measured the concentration of DNA based on its visualization and compared it with calculation obtained from spectrophotometer UV/VIS. The research results showed that the amount of DNA analysed using a spectrophotometer tend to similar with the measurement results using the MatLab-based software although there was differences in quantitative values.

Background: Noise reduction is a method for reducing CT dose; however, it can reduce image quality. Objective: This study aims to propose a selective mean filter (SMF) and evaluate its effectiveness for noise suppression in CT images. Material and Methods: This experimental study proposed and implemented the new noise reduction algorithm. The proposed algorithm is based on a mean filter (MF), but the calculation of the mean pixel value using the neighboring pixels in a kernel selectively applied a threshold value based on the noise of the image. The SMF method was evaluated using images of phantoms. The dose reduction was estimated by comparing the image noise acquired with a lower dose after implementing the SMF method and the noise in the original image acquired with a higher dose. For comparison, the images were also filtered with an adaptive mean filter (AMF) and a bilateral filter (BF). Results: The spatial resolution of the image filtered with the SMF was similar to the original images and the images filtered with the BF. While using the AMF, spatial resolution was significantly corrupted. The noise reduction achieved using the SMF was up to 75%, while it was up to 50% using the BF. Conclusion: SMF significantly reduces the noise and preserves the spatial resolution of the image. The noise reduction was more pronounced with BF, and less pronounced with AMF. [ABSTRACT FROM AUTHOR]