No abstract available

No abstract available

[en] Following a detection of abnormality of pituitary hormone, it is very important to know whether the abnormality is due to pituitary microadenoma for deciding treatment methods. To diagnose pituitary microadenoma, polytomography of the sella turcica has been used. The recently developed high resolution coronal CT scan is prone to be more valuable in diagnosing microadenoma. New findings by this method were reported. (Ueda, J.)

[en] Reports on the application of positron CT (PCT) to neuropsychiatric diseases were introduced, and this method was compared with conventional methods for the measurement of cerebral circulation/metabolism and with XCT. Currently, PCT is used in physiological study, the study of the intracranial distribution of chlorpromazine and measurements of the cerebral flow rate, glucose consumption and oxygen consumption in patients with Hungtinton's chorea, dimentia, epilepsy and schizophrenia. Their new data are available. (Chiba, N.)

[en] Colony-stimulating factors (CSF) which promote the growth of residual granulocyte-macrophage progenitor cells after radiation exposure was studied. CSF was isolated and purified from Yoshida's sarcoma cells (YS) and mouse fibroblast L-3P (L) respectively. The YS-CSF were inactivated by proteases, but the L-CSF were not. Conversely, only the L-CSF were inactivated as a result of oxidation by periodic acid. This result suggests that activity of these two substances are different. Because L-CSF could be separated into three fractions by chromatography, and all these three substances had same CSF activities, L-CSF, which were extracted from one cell line, were synthesized from several substances. It was shows that one CSF had two potential of differentiating progenitor cells and high concentration CSF differentiate the progenitor cells to granulocytes and low concentration to macrophages. However, in some cases, high concentration of YS- and L-CSF differentiated them to macrophages, suggesting that in the activities of CSF. (Nishio, M.)

[en] The possibility of the application of Xenon (Xe) as a CT contrast medium was studied. CT scanning was performed with a mixture of 50% Xe and 50% O₂ in a closed inhaler. Simple CT images of the basal nuclei of normal subjects and CT images produced by the enchancement of Xe of the basal nuclei of normal subjects were compared. Hounsfield numbers were compared before and 3 minutes after the inhalation of 50% Xe. When iodine and 50% Xe were compared for contrast characteristics, iodine had no contrast characteristic in the case of healthy cerebral blood vessels, but the brain itself was outlined clearly with Xe, which is very effective in the diagnosis of demyelinating diseases. Xe is also effective in the diagnosis of Huntington's chorea because it deeply stains basal nuclei. CT scanning with Xe possibly could be applied to diagnose cerebral diseases, such as leukodystrophy and encephalitis, which are difficult to diagnose with conventional CT, to determine cerebral tumor changes and cerebrovascular diseases, to determine the type of surgery, and to determine cerebral circulation. (Nishio, M.)

[en] Usefulness of CT arteriography was studied on 9 patients with histologically confirmed primary liver cancer. Plain CT images, CT venographic images, and CT arteriographic images of main focus in each patient were compared. CT arteriography visualized lesions as high density area against normal hepatic tissues. Therefore, it was easy to identify the existence and the extent of lesions by CT arteriography. It was also possible to detect small lesions which had been difficult to be detected by plain CT. (Tsunoda, M.)

[en] The efficacy and role of gamma knife (GK) in the treatment of various pituitary adenomas are described on author's experience and discussed with literature. GK subjects are 328 patients (M 126/F 202, av. age of 47.8 y) in author's hospital, and satisfactory follow-up (32-44 mo) for evaluation has been possible in 253 cases, who had tumors non-functional (129 cases), producing ACTH (23), HGH (70) and PRL (31). Stereotactic GK radiosurgery is done with navigation by Gamma Plan based on enhanced MRI images at various doses, and evaluation in the follow-up period is performed by hormonal levels and MRI which give efficacy of complete response (CR), partial response (PR), MR and standard deviation (SD)/ progressive disease (PD) on the tumor size. The overall tumor control rate is found to be 95-100%. Effectiveness (CR and PR) is found as high as 77.4% in PRL-producing tumor (marginal dose 14-32 Gy), 65% in non-functioning (15-25 Gy), 61% in ACTH (19-30 Gy) and 60% in GH (19-31 Gy), of which tendency is similar to that in literature. Even in ACTH-producing tumor, low ACTH and cortisol levels persisted with tendency of improved obese and hypertensive symptoms. GK radiosurgery has limitations in the tissue size and distance between the tumor and optic nerve/chiasm, but for the enough small tumor, it gives satisfactorily long term efficacy. (R.T.)

No abstract available

[en] Now, at more than 7 months after Fukushima Nuclear Power Plant Accident, public concern is on the internal radiation exposure (IE) as well as external one. Here explained are fundamentals for correctly understanding and assessing IE. IE dose in the unit Sv requires complex calculation on physical and biological dynamics of the radionuclide and its assessment is performed with the committed effective dose (CED). CED is the time-integrated dose rate (t=50 and 70 y in adult and child, respectively; the whole life) of total of each organ or tissue. Estimation of IE can be conducted through actual radioactivity measurement by smearing of nasal cavity, bioassay (measuring radioactivity in excreta) and external whole body counting. The first and second ones are used for measuring alpha- and beta-emitters. The whole body counter has a detector of NaI (Tl) scintillator or Ge-semiconductor to analyze the energy spectrum of X- or gamma-ray, necessary for radionuclide identification. Counting the radioactivity in the whole human body is done with the counter correctly calibrated using phantom. CED is calculated from the measured radioactivity (Bq) with consideration of its ingested time/route and effective half life of the nuclide with use of its coefficient given in International Commission of Radiological Protection (ICRP) publication 68. At Fukushima Accident, National Institute of Radiological Sciences (NIRS) and Japan Atomic Energy Agency (JAEA) conducted the assessment of CED in related residents. NIRS calculated CED assuming that IE had begun on Mar. 12, 2011 (the maximum IE assumption), and obtained the result that CED >1 mSv was in none of 109 people tested. In addition, analysis of urinary Cs-137 measured by NIRS also revealed that none had >1 mSv eq. IE of the nuclide. (T.T.)