Hypothetical mortality risk associated with spiral tomography of the maxilla and mandible prior to endosseous implant treatment.

Radiation dose delivered from the SCANORA radiography unit during the cross-sectional mode for dentotangential projections was determined. With regard to oral implantology, patient situations of an edentulous maxilla and mandible as well as a single tooth gap in regions 16 and 46 were simulated. Radiation doses were measured between 0.2 and 22.5 mGy to organs and tissues in the head and neck region when the complete maxilla or mandible was examined. When examining a single tooth gap, only 8% to 40% of that radiation dose was generally observed. Based on these results, the mortality risk was estimated according to a calculation model recommended by the Committee on the Biological Effects of Ionizing Radiations. The mortality risk ranged from 31.4 x 10(-6) for 20-year-old men to 4.8 x 10(-6) for 65-year-old women when cross-sectional imaging of the complete maxilla was performed. The values decreased by 70% when a single tooth gap in the molar region of the maxilla was radiographed. The figures for the mortality risk for examinations of the complete mandible were similar to those for the complete maxilla, but the mortality risk decreased by 80% if only a single tooth gap in the molar region of the mandible was examined. Calculations according to the International Commission on Radiological Protection carried out for comparison did not reveal the decrease of the mortality risk with age and resulted in a higher risk value in comparison to the group of 35-year old individuals in calculations according to the Committee on the Biological Effects of Ionizing Radiations.

Dosimetry and cost of imaging osseointegrated implants with film-based and computed tomography.

Thermoluminescent dosimeters were used to measure radiation doses at craniofacial sites in a tissue-equivalent phantom during film-based multidirectional tomography with the Tomax Ultrascan (Incubation Industries, Ivyland, Pa.) and during computed tomography with the Elscint Excel 2400 (Elscint Corp., Tel Aviv, Israel). Mean absorbed doses for presurgical mandibular and maxillary canine and molar implant assessments were converted to equivalent doses, which were then multiplied by published weighting factors and summed to give effective doses. The computed tomography device consistently delivered higher doses than the Tomax Ultrascan to all anatomic locations; the differences were most pronounced when only one or two implant sites were evaluated. The reasons for the dose disparities are considered both anatomically and procedurally. A survey of examination cost revealed film-based multidirectional tomography to be less expensive than computed tomography.

Morbidity after temporomandibular joint arthrography is lower than after removal of lower third molars.

The morbidity after temporomandibular joint arthrography was studied as the amount of pain, use of pain medicine, and disturbed sleep and was compared with the morbidity after removal of lower third molars. The morbidity was substantially higher after surgery than after arthrography. It was concluded that the morbidity after arthrography can be kept at a low level and that it should not restrict the indications for this examination.

How invasive is TMJ double-contrast arthrography in combination with cinematography? Patient discomfort versus known diagnostic gain.

There is no doubt that double-contrast TMJ fluoroscopic tomography enables a differential diagnosis and treatment in internal derangement pathosis. Its indication is, apart from the expected diagnostic gain, also determined by the degree of its invasiveness, and other alternative diagnostics being available (nuclear magnetic resonance). Data on patient discomfort and complications were gathered in 63 arthrotomographies; pain sensations and mandibular mobility, during and after the procedure in particular, were studied. We consider, along with Westesson, the procedure to be less invasive than commonly considered, once the surgeon-radiologist has gained enough experience.

Standard and computed tomography in the evaluation of neoplasms of the chest. A comparative efficacy assessment.

Although in practice computed tomography (CT) has nearly replaced standard tomography in the evaluation of chest diseases, an analysis of the literature shows that standard tomography may be preferred in some settings. After a detailed review of studies on test performance, we calculated overall sensitivity and specificity values. Using Bayesian analysis, we then developed guidelines for choosing between computed and standard tomography. A test is recommended if its results might obviate the need for an invasive procedure. Standard tomography is recommended in the detection of mediastinal metastases from lung cancer. In the detection of hilar metastases, standard tomography is recommended for patients who have low pretest probabilities of metastases to this site, and computed tomography is recommended for patients who have high pretest probabilities. Computed tomography is recommended for the detection of calcification in solitary pulmonary nodules. Tomographic procedures are not recommended when the pretest probability is intermediate. The discrepancy between current practice and these guidelines highlights the need for carefully designed, multi-institutional comparative studies of radiographic procedures.

Intravenous urography in children: is routine tomography useful?

We have evaluated the usefulness of routine nephrotomography in pediatric uroradiology. We reviewed all of the intravenous urograms done on children under 12 years of age, over a period of 18 months. In only 13 of 81 examinations (16%) was additional information obtained from tomography. It made no difference whether the patient could or could not cooperate during the study. In view of the cost of the extra films and the increase in radiation exposure, we therefore concluded that routine nephrotomography in pediatric intravenous urography is not indicated.

[Arthrotomography of the normal temporomandibular joint. Anatomy, technic and complications. I]. / Arthrotomographie des normalen Kiefergelenkes. Anatomie, Technik und Komplikationen.

Most abnormalities in the T.M. joint are due to pathological processes in the meniscus or joint capsule. They usually manifest themselves as an anterior luxation of the meniscus, which cannot be demonstrated by conventional radiological examination, even including tomography. In order to evaluate the meniscus, it is necessary to perform a contrast examination of the inferior joint space. The technique has proved valuable in 280 patients (308 arthrograms). The method is described and radiological anatomy is discussed. There were no significant complications in our series.

Arthrotomography of the temporomandibular joint: new technique and preliminary observations.

A technique for arthrography of the temporomandibular joint using multidirectional tomography is described that greatly simplifies interpretation. In 21 attempts, 20 successful arthrograms were obtained in patients complaining of pain, tenderness, and clicking and locking of the joint who had not responded to conservative therapy. Abnormalities demonstrated were perforation of the meniscus, anterior dislocation and subluxation of the meniscus; and redundancy of the bilaminar zone. In all 11 patients who underwent surgical meniscoplasty, disc abnormalities included thinning, perforation, flaccidity, and bilaminar redundancy. No permanent complications of the arthrographic procedure occurred, but temporary postprocedure discomfort was frequent. This preliminary experience with temporomandibular joint arthrotomography suggests this easily performed procedure offers reliable information about disc function and integrity that may assist in a selection of patients for meniscoplasty and other surgical treatment.

[Complications with ossovenography and discography in the cervical area (author's transl)]. / Komplikationen bei Ossovenographie und Diskographie im Halsbereich.

Report on 3 cases of incidents or complications in discography and ossovenography. 1 patient developed reversible damage of the glossopharyngeal and recurrent nerve through hematoma following assovenography. Another patient developed aseptic discitis, the third infective discitis with parpharyngeal involvement. Pain and defects disappeared in all patients after treatment. Their causes are discussed. These rare complications do not represent contraindications considering the value of the diagnostic techniques.

Radiation dose to the eyes of patients during petrous bone tomography--a comparative survey.

Some investigation has been made in recent years of radiation dose to the eye during radiological procedures. A comparative survey has been made of eye dose during petrous bone tomography in different departments on different tomographic units and during different types of examination. Doses of up to 4 rad per exposure have been recorded and various methods of reducing the dose have been investigated, the most successful being the use of 1 mm lead eyeshields or examining the patient in the posteroanterior position.

[Absorbed dose by the crystalline in middle ear tomography (author's transl)]. / Dose absorbée par le cristallin au cours des tomographies de l'oreille moyenne et interne

Measurements of the incident dose on the eye have been taken during the tomographic examinations of the middle ear. These measurements have been effectuated without any protection of the eye, and with a Pb-diaphragm protection, thickness 2mm. The tomograph which has been used is an Italian one (Eurostrator-Zuder, Genoa) provided with complex radiation movements (circular, spiral) and which gives technical resutlts such as the Polytom (generally used for these researches) but which has a focus film distance of 1m instead of 1.40 m. The average incident dose on the erystalline lens is high (11.7 R): the use of the Pb-diaphragm reduces the dose considerably (0.65 R) without any significant imperfections on the radiological image.