X-ray fluoroscopy has been used not only for diagnoses but also for treatment, as in interventional radiology. The aim of this study is to assess the usefulness of the signal-to-noise ratio (SNR) using the subtraction method, which is used in the quality assurance/quality control (QA/QC) of magnetic resonance imaging (MRI) equipment, and image visibility using the Howlett chart method in the fluoroscopic examination. The fluoroscopy unit has a detector with an image intensifier and a color liquid crystal display. A 2620 dosimeter and an ionization chamber were selected for the dose measurement. Fluoroscopic images for visual and physical evaluations were collected as dynamic data. The skin surface absorbed dose rates for each tube current were measured using a dosimeter. The SNR using the subtraction method and image visibility using the Howlett chart method were examined. The results from both indicate that as the SNR improves, visual evaluation increases, but the rate of increase gradually saturates. Therefore, physical and visual evaluations are possible with the SNR using the subtraction method and the image visibility using the Howlett chart method.
Cite this paper
Nishihara, S. , Yamashita, Y. , Kawai, N. and Otsuka, H. (2014) Usefulness of the SNR Using the Subtraction Method and Image Visibility Using the Howlett Chart Method in X-Ray Fluoroscopic System. Open Journal of Medical Imaging
, 49-56. doi: 10.4236/ojmi.2014.42007
 Yamao, Y., Yamakado, K., Takaki, H., Yamada, T., Murashima, S., Uraki, J., Kodama, H., Nagasawa, N. and Takeda, K. (2010) Optimal Scan Parameters for CT Fluoroscopy in Lung Interventional Radiologic Procedures: Relationship between Radiation Dose and Image Quality. Radiology, 255, 233-241. http://dx.doi.org/10.1148/radiol.09090733
 Honda, M., Kitadani, S. and Ishii, H. (2007) Observer Performance for a Linear Pattern with Different Frequency Characteristics of Background Random Noise. Proceeding of the 2nd International Conference on Complex Medical Engineering-CME, Beijing, 23-27 May 2007, 1471-1476.
 Tapiovaara, M.J. (1993) SNR and Noise Measurements for Medical Imaging: II. Application to Fluoroscopic X-Ray Equipment. Physics in Medicine and Biology, 38, 1761-1788. http://dx.doi.org/10.1088/0031-9155/38/12/006
 Tapiovaara, M.J. (1997) Efficiency of Low-Contrast Detail Detectability in Fluoroscopic Imaging. Medical Physics, 24, 655-664. http://dx.doi.org/10.1118/1.598076
 Ogura, A., Miyai, A., Maeda, F., Fukutake, H. and Kikumoto, R. (2003) Accuracy of Signal-to-Noise Ratio Measurement Method for Magnetic Resonance Image. Nihon Hoshasen Gijutsu Gakkai Zasshi, 59, 508-513. (in Japanese)
 Aufrichig, R., Xue, P., Thomas, C.W., Gilmore, G.C. and Wilson, D.L. (1994) Perceptual Comparison of Pulsed and Continuous Fluoroscopy. Medical Physics, 21, 245-256. http://dx.doi.org/10.1118/1.597285
 Tapiovaara, M.J. and Sandborg, M. (2004) How Should Low-Contrast Detail Detectability be Measured in Fluoroscopy? Medical Physics, 31, 2564-2576. http://dx.doi.org/10.1118/1.1779357
 Yoshizawa, H. (2001) Image Quality Evaluation of Digital Radiography (DR) System Using Howlett Chart. The Journal of Tokyo Academy of Health Sciences, 3, 257-261. (in Japanese)
 Dainty, J.C. and Shaw, R. (1974) Image Science. Academic Press Inc., New York.
 US Department of Health and Human Services, Bureau of Radiological Health Report (1982) MTF’s and Wiener Spectra of Radiographic Screen-Film Systems. HHS Publication FDA 82-8187, Rockville.