嚥下ビデオ透視検査時の被検者の放射線被曝線量を推定するため, 線量測定用の人体型ファントムを用いて器官ごとの線量測定を行なった。水晶体・下垂体・耳下腺・舌下腺・顎下腺・甲状腺・乳房・卵巣・精巣の各器官について, 標準的な検査条件での1分間あたりの臓器線量を測定した。線量の最大はX線管側顎下腺の2,598μGy/min, 最小は卵巣の0.13μGy/minであった。照射野の境界近くにある耳下腺や甲状腺では, 照射野の大きさのわずかな差で, 線量が大きく変わることが示唆された。放射線に対する感受性が高いとされる甲状腺で, 検査1回あたりの被曝によるガンの発生確率を計算すると, 0.00016%から, 多く見積もっても0.0012%となり, 個々の器官でガンが発生する確率は, これを超えることはないと考えられた。

Organ doses to patients from the videofluorographic examination of swallowing were estimated on the basis of a dosimetric experiment with thermoluminescent dosimeters placed at several sites of organs in a man-shaped phantom. Doses per minute under a standard condition of examination were measured for organs such as lens, pituitary gland, parotid gland, sublingual gland, submandibular gland, thyroid gland, breast, ovary, and testis, The maximum dose obtained in this experiment was 2,598μGy/min for submandibular gland, while the minimum dose was 0.13μGy/min for ovary. Concerning parotid gland and thyroid gland, which were near the border of the area of radiographic beam, it was suggested that small differences in width of the area of radiographic beam could strongly affect the doses to these organs. The probability of thyroid cancer per examination was calculated, and the value was estimated to be 0.00016 to 0.0012%. Since thyroid gland is considered vulnerable to radiation, it can be concluded that the probabilities of cancer for other individual organs may not be more than this value.

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