Basic Radiographic Technique and Normal Anatomy

摘要: Several technical factors are essential for good radiography of the sinuses. These include accurate coning incident beam, a fine focal spot X-ray tube, and Potter Bucky or grid to obtain maximum contrast. The standard projections which may be employed are: 1. Occipito-rnental projection. subject sits facing film radiographic base line is tilted 45°. thcident beam horizontal centred on occipital bone 3 cm above external protuberance (Fig. 1.1). With most subjects tube tilt unnecessary since they can readily extend head required position, but in older persons it necessary slightly compensate any restricted extension head. This view shows maxillary antra free overlap petrous bones, if mouth kept open during examination sphenoid sinuses nasopharynx seen through 1.2). 2. Occipito-frontal with orbito-meatal raised 20°, nasion 1.3). projection demonstrates detail frontal sinuses; lateral walls also seen, although overlapping temporal bones largely obscure 1.4). 3. Lateral sagittal plane parallel film. antrum 1.5). super-imposition both detracts somewhat from value this An alternative version sinus projection, better nasopharyngeal air spaces, high kilovolt using 1 50 kV mm brass filtration 1.6). 4. Submentovertical extended so that vertex rests against table top between angles jaw at right 1.7). In middle-aged elderly patients has upwards considerably as few age group attain degree bring skull orbital 1.8). 5. Oblique Rotation an angle 39° will enable posterior ethmoid cells projected orbit show these clear shadows. optic foramen end-on