The Effect of Dose Reduction on Image Quality in Digital Radiography Using a Flat-panel Detector: Experimental Study in Rabbits

PURPOSE: To evaluate the effect of dose reduction on image quality in digital radiography using a flat-panel detector. MATERIALS AND METHODS: Digital radiographs of 30 rabbits were obtained at two different dose levels (33.23 µGy for the standard dose group and 20.09 µGy for the reduced dose group). The amorphous selenium-based flat-panel detector system had a panel size of 7x8.5 inches, a matrix of 1280x1536 (pixels?), and a pixel pitch of 138 µm. Four observers evaluated the soft-copy images on a high-resolution video monitor (2560x2048x8 bits) in random order. The observers rated the visibility of 13 different anatomic structures on a 5-point scale, viz. the retrocardiac lung, subdiaphragmatic lung, heart border, diaphragmatic border, proximal airway, unobscured lung, liver border, kidney border, bowel gas, flank stripe, ribs, and vertebrae in the mediastinal and abdominal regions. Statistical significance was determined using Wilcoxon's signed rank test. RESULTS: There was no statistically significant difference in the visibility of the anatomic structures on digital radiography between the standard and reduced dose groups. CONCLUSION: Digital radiography using an amorphous selenium-based flat-panel detector can preserve the image quality, even though the does is reduced to 40% of the standard level.

Comparison of Two Internet Based Telepathology Systems: CORBA and ActiveX System / 대한의료정보학회지

Telepathology systems will be common systems in hospitals. The two systems were designed and implemented in web environments for test. One was implemented with the Common Object Request Broker Architecture (CORBA) technique. The other system was implemented in the form of ActiveX. The histopathological materials were stained by Hematoxylin and Eosin. By the Donpisha CCD camera attached to an Olympus BX-51 optical microscope 180 color images come to be acquired. For evaluation of the systems, transmission times and telediagnosis concordance rates were measured. Image processing ability was tested using two telepathology systems. For the local area test, system I using CORBA had measured image transmission times of 0.1 s, 0.2 s, and 0.4 s at the file sizes of 100 K byte, 900 K byte and 3.6 M byte respectively. Transmission times for system II using Component Object Model (COM) were slightly slower, ranging from 0.02 s to 0.05 s. In the long distance area test, system II transmission times were 0.5 s, 0.8 s, and 2.0 s. The overall concordance rate of telediagnosis for the 180 images was 78.3%. In this study, we compared our systems about image transmission, and processing for the further development of system configurations.

Quantitative Analysis of Patellar Tendon Reflexes with Newly Designed Percussion Instrument

OBJECTIVE: There has been some existing problems with the electrical reflex hammer. The occurrence of pressure build up with percussion and change of hammering points is one example. In order to make improvements on this device, we conducted studies with a newly designed percussion instrumental stimulator. METHOD: The data collected from the first group was based on the manual percussion of electrical reflex hammer on the patella ligament. The data collected from the second group by usage of a newly designed instrumental stimulator maintained steady pressure and time and target position on the electrical reflex hammer. Comparisons were made between the two group. RESULTS: Our single measure of latency and amplitude on the manual and instrumental percussion group resulted in the reliability of 84.67%, 91.23%, 73.63%, and 83.29%. The 10 repeated measure of latency and amplitude on the manual and instrumental percussion group resulted in the reliability of 99.95%, 99.97%, 99.90%, and 99.94%. CONCLUSION: From our experiment on the tendon reflex, we found out that it is important to have an instrumental stimulator that can maintain steady pressure while it is applying percussion to accurate data. On manual percussion, it is important to obtain data based on mean value of repeated measurements.