Radiologia diagnostica最新文献

A method for measuring the fraction of extrafocal radiation in the x-ray output of x-ray tubes was developed and tested under clinical conditions. A fraction of 10% was found, that increases with tube voltage and field size, while tube current and focal spot size have no influence. As a measure for the influence of off-focus radiation on image quality the contrast transfer function was used. Off-focus radiation causes detectable geometric unsharpness. If screen-film-systems are used, the unsharpness is negligible compared with the screen unsharpness. Ways for reducing off-focus radiation from medical x-ray tubes are discussed.

The comparison of mammographic image recording systems TF-13-nonscreen film and ORTHO-MA with MIN-R screens leads to the necessary conclusion, that mammography should be carried out only with screen film combinations and an anti-scatter grid. This means improved contrast and a reduction of radiation dose to 1/3 of the dose of TF 13. Since in the GDR the film XR 10 still is used as mammographic film the fourfold of the internationally possible dose is required. The urgent change of the situation can only be achieved with respective imports.

The quality of 96 infusion cholegraphies with isotonic Ioglycamide-85 solution and of 2,080 infusion cholegraphies with hypotonic adipiodone-50 gave equal images in 97% of the cases. Ioglycamide-85 caused side-effects in 15.6%, Adipiodone only in 1.5% of the cases. For improved compatibility of Ioglycamide and of new contrast media as Iotroxamide and Idoxamide the use of hypotonic solutions is recommended for infusion. Their concentration should be osmotically tolerated by the erythrocytes. For the prevention of liver necrosis by contrast media the amount of contrast medium should be limited to 10 g meglumine salt.

On the background of a continuous increase of knowledge in urologic oncology, the need for actual information and for interdisciplinary cooperation we discuss the diagnostics of prostatic and cystic carcinoma from the standpoint of the required therapy. The threshold of diagnostic detectability of prostatic carcinoma today is approximately the size of a matches head. By transrectal sonography and MRT the anatomic zones of the prostate are imaged and a selective biopsy becomes possible. Morphometric studies of prostatic carcinoma with pathologic-anatomical descriptions of the tumour volume and capsular penetration are described. The requirements for medical imaging for sufficient information on tumour volume, seminal bladder infiltration, capsular infiltration and lymph node diagnostics are derived. For the diagnostics of bladder carcinoma the significance of the lamina propria as a separating membrane between superficial and infiltrating carcinoma is discussed. Possibilities and limitations for the T- and N-determination of infiltrating carcinoma with CT and MRT and new therapy concepts (neoadjuvant chemotherapy) for the muscle-infiltrating cystic carcinoma are discussed.

Knowledge of the radiopacity of bromine-containing hypnotics and of halogenated hydrocarbons has led to numerous recommendations and speculations. Supported by own investigations the sensible application of a rapid radiological determination in the practice of clinical toxicology is discussed. This should always be carried out, if solvent residues, gastric contents or gastric lavage fluid are available, a ingestion is suspected, and the result of chemical analysis is not promptly obtainable. However, a hint at the group of halogenated hydrocarbons is only possible, if additional information about miscibility with water is accessible. Revealing the presence of radiopaque material in tablet or liquid form by radiologic studies of the abdomen may be very helpful for the rapid evaluation of symptomatology and first therapeutic consequences, but it does not allow any chemical identification of the poison.

The amount of radiation committed to the patient is best described by appropriate organ doses. Methods for determining such dose values are described. For x-ray investigations of the chest, thoracic and lumbar spine, pelvis and kidney (excretion urography) our own organ-dose values are compared with those from the literature.

Sonography provides a safety in dignity that is comparable to mammography while its overall sensitivity is higher. Mammography remains the method of choice. All mammographically unclear cases should be elucidated with sonography. For this reason an integration of a sonographic device and a mammography unit is advisable.