Radiographic Techniques Lecture Notes PDF

Radiographic techniques Mammography, main position, finding, image interpretation  :BY Ahmed Jasem Abass  MSC of Medical Imaging Mammography Techniques  Mammography is the radiographic examination of the breast tissue (soft tissue radiography). To visualize...

Radiographic techniques Mammography, main position, finding, image interpretation  :BY Ahmed Jasem Abass  MSC of Medical Imaging Mammography Techniques  Mammography is the radiographic examination of the breast tissue (soft tissue radiography). To visualize normal structures and pathology within the breast. A low kVp value, typically 28 kVp, is used. Radiation dose must be minimized due to the radio-sensitivity of breast tissue. Mammography is carried out on both symptomatic women with a known history or suspected abnormality of the breast and as a screening procedure in well, asymptomatic woman. Consistency of radiographic technique and image quality is essential, particularly in screening mammography. Whilst other techniques such as magnetic resonance imaging (MRI) and ultrasound have a role in breast imaging. Q What is mammography?  Recommended projections  Basic  45-degree medio-lateral oblique  Projections (Lundgren)  Craniocaudal  Radiographic techniques :- It is used to diagnose or treat patients by recording images of the internal structure of the body to assess the presence or absence of disease, foreign objects, and structural damage or anomaly. A mammography system comprises:  A high-voltage generator  X-ray tube  tube filtration  compression device  image-recording system  automatic exposure control (AEC) system. Radiological considerations  Lesion characteristics  Four main types of lesion are visible mammographically, namely masses, calcifications, architectural distortion and density, each of which is assessed according to a variety of features:  Masses  Masses are assessed by shape, margin and density. The shape may be round, oval, irregular or lobulated. Benign lesions tend to be round or oval and well-defined, whereas malignancies tend to be irregular in shape and are often hyperdense. A low- density lesion suggests fat and is usually benign. Calcifications  Calcifications vary in size, shape, number, grouping and orientation. There are many typically benign forms of calcification, such as dermal, vascular and popcorn calcifications. Milk of calcium has a characteristic teacup shape on the oblique projection. Many types of rod- and ring- like calcifications are also benign. Malignant calcifications are often grouped, linear and irregular in size, shape and separation. Architectural distortion  Architectural distortion is a feature of many carcinomas. It also occurs with benign conditions, such as sclerosing adenosis. In most of these cases, it can be proven benign only by histology.  Focal increased density may be a sign of malignancy, but it has low specificity unless combined with other features. Benign disease may also cause asymmetric increased density, but focal density is regarded with suspicion.  Other features may be present, such as skin thickening, and nipple retraction. These are assessed with the main features outlined above. Other techniques  Ultrasound is the most widely used and readily available alternative imaging technique. It is the best test for determining whether a lesion is a cyst. Other fluid-containing diseases may also be detected, such as abscesses.  Ultrasound gives different tissue information from that obtained by X-ray (e.g. homogeneity of tissue, acoustic shadowing), making this a useful supplementary tool. It also allows assessment of surrounding tissue and vascularity. It may be used, therefore, to assess mammographically indeterminate masses or to guide core biopsy. In younger patients, where the density of breast makes mammography less sensitive and where suspicion is lower, ultrasound has an important role in  diagnosis and avoidance of radiation exposure. Being a real- time technique, ultrasound is simpler and faster and will be the guidance method of choice for most techniques. Magnetic resonance imaging  MRI is expensive, relatively time-consuming and not available widely. Some patients cannot tolerate it due to claustrophobia. In addition to showing the morphological features demonstrated by other modalities. 45-degree medio-lateral oblique (MLO) basic – Lundgren’s oblique  Position of patient and cassette  The mammographic equipment is routinely angled at 45 degrees from the vertical. However, the precise angulation required will depend on the woman, e.g. for a very thin  woman, the breast-support table will be almost vertical.  The marker is oriented vertically to prevent confusion of the image with those produced by other mammographic projections.  The woman faces the equipment, with the breast about to be examined closer to the breast-support table.  The woman’s arm is placed on the top of the table, with the elbow flexed and dropped behind it. The table height is adjusted so that the lower border of the breast is 2–3 cm above the edge of the film. 45-degree medio-lateral oblique (MLO) basic – Lundgren’s oblique  The radiographer places his or her hand against the rib cage and brings the breast forwards, with his or her thumb on the medial aspect of the breast. The breast is gently extended upwards and outwards to ensure it contacts the breast-support table. This is aided by leaning the woman forward.  The shoulder on the side under examination extended to ensure inclusion of the axilla, the axillary tail and as much as possible of the breast tissue.  The compression plate is applied to fit into the angle between the humeral head and the chest wall.  When the compression is almost complete, the breast is checked for skin folds.  The nipple must be in profile. To ensure that the entire breast back to the chest wall margin is included. 45-degree medio-lateral oblique (MLO) basic – Lundgren’s oblique Essential image characteristics  The axilla, glandular tissue, pectoral muscle should be demonstrated.  When both medio-lateral oblique projections are viewed together ‘mirror image’, they should be symmetrical, matching at the level of the pectoral muscle as a deep ‘V’ and at the inferior border of the breasts. Cranio-caudal – basic  Position of patient and cassette  The mammography equipment is positioned with the X-ray beam axis pointing vertically downwards.  The woman faces the machine, with her arms on her sides. She is standing and is rotated 15–20 degrees to bring the side under examination close to the horizontal breast-support table. The table is at the level of the infra-mammary crease.  The radiographer stands on the side of the woman that is not being examined and lifts the breast up in the palm of the hand to form a right-angle with the body. It is rested on the breast support table. The nipple should be in the midline of the breast and in profile.  Film makers are placed on the axillary side of the film close to the woman’s axilla and well away from the breast tissue. Cranio-caudal – basic  The woman’s head is turned away from the side under examination, and the shoulder on the side under examination is dropped to coverage the lateral posterior portion of the breast, to bring the outer quadrant of the breast in contact with the breast-support table, and to relax the pectoral muscle.  Remove any skin folds of the breast and is also stretched carefully across the film support.  The breast is compressed firmly to a level that the woman can tolerate. This should result in an equal thickness of tissue anteriorly and posteriorly.  Care must be taken when the compression is applied to ensure that exposure is immediate. Compression must be released as soon as the exposure ends. Cranio-caudal – basic Essential image characteristics No overlying structures should be seen. The nipple should be in profile and shown in the midline of the film. There should be no folds in the breast tissue. Thank You