Magnification Radiography

ISBN-13: 9783642661228 / Angielski / Miękka / 2011 / 112 str.

A. S. Takahashi; S. Sakuma

Opis

If the early stages of a disease begin with the involvement of a small area of cells or tissue, the early diagnosis of pathologic changes by means of radio graphy should concentrate first on the detection of such minute changes. The ideal solution would be to produce X-ray images of findings much finer than those observable by the naked eye, and herein lies a new field of research that is believed to be worth developing. The introduction of a 0.3 mm focal-spot rotating-anode tube about 25 years ago opened the way to the clinical application of magnification radiography. Due to the postwar economic situation, we were unable to import this type of X-ray tube, but we believed in the importance of magnification radiography in X-ray diagnosis, and in 1952 we produced an X-ray tube with a 0.15 mm focal spot by reconstructing an existing fixed-anode tube. This X-ray tube has been improved step by step, so that tubes with focal spots of 0.1 mm or 0.05 mm are now available in Japan. Thus it has become possible to obtain 4 to 6 x magnification images of minute lesions that could not be imaged by normal roentgenography."

Spis treści

I. Principles of Magnification Radiography.- A. Magnification Radiography in General.- B. Historical Review.- C. X-Ray Tube.- 1. Focal Spot.- 2. Measurement of Focal Spot Size.- a) Pinhole-Camera Method.- b) Estimation with Resolving Power.- c) Calculation with Resolving Power.- d) Calculation with MTF Curves.- 3. Output.- D. Specific Effects in Magnification Radiography.- 1. High Detectability.- a) Resolution.- b) Background Dispersion.- 2. Disappearance of Image of Very Small Object.- a) Filter Effect Due to Penumbra.- b) Filter Effect Due to Scattering.- c) Filter Effect Due to Contrast.- 3. Magnified Blur Due to Motion.- 4. Improvement of Visibility Due to Superposition.- 5. Variability of Magnification Ratio.- E. Image Quality.- F. Radiation Protection of the Patient.- 1. Skin Dose.- 2. Size of Radiation Field.- 3. Depth and Volume Dose.- 4. Body Thickness.- 5. High-Voltage Technique.- 6. Patient Dose Reduction in General.- II. Technique of Magnification Radiography in Clinical Practice.- A. Equipment for High-Magnification Radiography.- 1. Magnification Radiography Unit for General Use.- 2. Magnification Angiography Unit.- 3. Fluoroscopy Unit Attached with Magnification Radiography Adaptor.- B. Accessories for Magnification Radiography Unit.- 1. Filter and Cone.- 2. Grid.- 3. Intensifying Screens and Film.- C. Positioning.- 1. Positioning Based on Anatomical Knowledge.- 2. Positioning Based on Interpretation of Previously Taken Normal Roentgenogram.- 3. Positioning by Means of X-Ray Television.- D. Magnification Ratio.- 1. Definition of Magnification Ratio.- a) Magnification Ratio Relative to Lesion.- b) Magnification Ratio Relative to Skin Dose.- 2. Determination of Magnification Ratio for Non-Moving Organ.- 3. Determination of Magnification Ratio for Moving Organ.- E. Adequate Field Size.- F. Test Marker.- G. Exposure Factors.- H. X-Ray Television Magnification Fluoroscopy.- III. Clinical Significance of Magnification Radiography.- A. Magnification Radiography Conducted with Small Focal-Spot Tubes.- B. Magnification Radiography without Administration of Contrast Media.- Case 1 (Bone): Gout.- Case 2 (Chest): Silicosis.- C. Magnification Radiography with Administration of Contrast Media.- Case 3 (Abdomen): Atrophic Hyperplastic Gastritis and Gastric Ulcer.- Case 4 (Chest): Embolism of Oily Contrast Medium in Lung.- Case 5 (Chest): Bronchial Asthma.- Case 6 (Chest): Chronic Obstructive Pulmonary Disease.- Case 7 (Salivary Gland): Sjögren Syndrome.- Case 8 (Abdomen): Mucosal Pattern of Small Intestine.- D. Magnification Radiography of Vessels.- Case 9 (Popliteal Fossa): Carcinoma of the Skin.- Case 10 (Chest): Chronic Obstructive Pulmonary Disease.- Case 11 (Chest): Pulmonary Carcinoma.- Case 12 (Chest): Mediastinal Tumor.- Case 13 (Abdomen): Carcinoma of Body and Tail of Pancreas.- Case 14 (Abdomen): Renal Cell Carcinoma.- References.