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The cone beam CT equipment 3DX is a dose-effective and a cost-effective alternative to helical CT for the diagnostic evaluation of osseous abnormalities of the mandibular condyle.

The absorbed doses of the 3D Accuitomo of the organs in the primary beam ranged from 1-5 mGy, and were several to ten times lower than other doses. The effective dose of the 3D Accuitomo ranged from 18 muSv to 66 muSv, and was an order of magnitude smaller than the others. In conclusion, these results show that the dose in the 3D Accuitomo is lower than the CB MercuRay and much less than MDCT.

The authors evaluated the imaging performance of cone-beam computed tomography (CBCT) for dental use using 3DX multi-image micro-CT (Morita Co., Kyoto, Japan) and four-row multi-detector helical computed tomography (MDCT) using an Asteion (Toshiba, Tokyo, Japan). A dried right maxillary bone was cut into eight slices 2 mm thick toward the zygomatico-palate and used as a phantom. Images of the phantom were then taken using 3DX and MDCT. The images of two bone slices were evaluated by five dentists for image quality and reproducibility of cancellous bone, as well as enamel, dentin, pulp cavity, periodontal ligament space, lamina dura and the overall image. Using the MDCT images as the standard, the 3DX images were evaluated with a subjective 5-level scale: 3 for an image equal to the MDCT image, 4 or greater for better, and 2 or lower for worse. The scores for all parameters exceeded 4 points. Maximum mean score was 4.8 for the lamina dura. Statistically significant differences were found for all items (P < 0.01). Our subjective evaluation of imaging performance clarified that 3DX was superior to MDCT. The results of this study suggest that 3DX is useful for imaging in the dental field.

Three hundred and twenty autopsy cases of sarcoidosis in Japan were analyzed to determine the pathological changes in the early stage, the mode of progression in each organ and the changes in the final stage of the disease. The lung and the mediastinal lymph nodes were affected in most of the cases, while the lesions were limited to the lung and intrathoracic nodes in some of the cases. It was suspected that early changes developed in the lung and in the hilar, and then in the mediastinal lymph nodes. The progression of sarcoid granulomas in the lung was classified into three patterns: (i) probably of a disseminated hematogenous nature; (ii) of an interstitial lymphogenous nature; and (iii) of a local expansive nature. These three patterns were observed also in the heart. In the brain, perivascular granuloma formation was a prominent feature. In the other organs in which sarcoid lesions were not malignant nor disseminated and conglomerated, no interstitial patterns were observed. In chronic cases, repeated dissemination and particularly the interstitial spread of granulomatous changes led to a prominent interstitial fibrosis and dysfunction of the organs, finally resulting in death of the individual. In such longstanding cases, the mediastinal nodes deteriorated by hyalinous degeneration of the granulomas, and many active granulomas were formed in the intra‐abdominal or body surface lymph nodes. These lymph nodes were likely to continue supplying sensitized lymphocytes to the whole body. A persistence of active change in the lymph nodes and the lymphogenous spread of granulomas in organs would appear to be key factors in the prognosis of sarcoidosis.

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These results suggest that bone thickness measurements of the RGF by 3DX imaging was effective.