EVALUATION OF A RADON AIR MONITOR IN THE MEASUREMENT OF RADON CONCENTRATION IN WATER IN COMPARISON WITH A LIQUID SCINTILLATION COUNTER.

The World Health Organisation (WHO) recommends that the concentration of radon in water should be no more than 100 kBq m-3 (100 BqL-1) and the Codex Alimentarius Commission states that the limit of quantification (LOQ) of a method should be no more than one-fifth of this value. In this study, a degassing method with an RAD7 device was used to measure radon concentrations in water, compared to a liquid scintillation counter (LSC) method used as the reference, to investigate whether the numerical value of the LOQ of this method was more than 1/5 (20 kBq m-3) of 100 kBq m-3. The degassing method with leak prevention was shown to reach a target value of 20 kBq m-3 or less under a relative humidity of 6% or lower in the chamber of the RAD7 device. Accordingly, the RAD7 degassing method with leak prevention can be used to accurately measure radon concentrations in water within the guidance level set out by the WHO.

Primary hepatic carcinoid tumor with metachronous lymph node metastasis after long-term follow up.

A case of hepatic carcinoid tumor occurring in a 71-year-old man is reported. The tumor was diagnosed initially as a hepatocellular carcinoma, and was then shown after resection histologically to be a carcinoid tumor. The tumor cells formed small nests and trabeculae separated by fibrous septa and were positive for Grimelius staining. Immunohistochemically, most of the tumor cells stained positive with chromogranin A and neuron-specific enolase. After a follow up for 5 years and 7 months, the patient developed tumors in lymph nodes between the remnant liver and the lesser curvature of the stomach with no tumors in other organs. Histologically, the tumor cells in the lymph nodes demonstrated a pattern of the immunostainings consistent with carcinoid tumor. After lymphadenectomy, the patient is free from recurrence in the regional lymph nodes for more than 1 year. This case is con-sidered to be a primary hepatic carcinoid tumor with metachronous lymph node metastasis.