111In-DTPAによるRI Cisternographyの検討

RI CISTERNOGRAPHY WITH 111IN-DTPA

I．はじめに

　RI cisternographyは，頭蓋内のCSF flowのme—chanism及び，くも膜下腔の状態を知るための補助的検査法であるが，正常脳圧水頭症の診断はもとより，近年では，脳腫瘍，脳硬塞に対してもその診断的価値は認められつつある^1）。従つてRI cisternographyの使用頻度は，今後ますます増加し，routineな検査法になると考えられるが，一方，RIの使用により，その人体に及ばす影響，排泄物の処理など，新たな医学社会上の問題が発生してきている。

　すなわち，診断的価値を低下させる事なく，より半減期の短い放射性医薬品を開発することは，必須の課題であり，我々は，この観点にたつて，¹¹¹In-DTPAによるRI clsternographyの試みを続けてきた。

In contrast to ¹⁶⁹Yb-DTPA the usage of ¹¹¹InDTPA, a new radiopharmaceutical, is not as yetpopular for RI cisternography. This report dealswith a comparative study of these two radiophar-maceuticals for RI cisternography.

For the past one year 301 RI cisternographieswere performed in 160 cases at the NeurosurgicalSurvice of Shizuoka Rosai Hospital. Among those¹⁶⁹Yb-DTPA was used in 137 occasions, ¹¹¹In-DTPAin 53, and both ¹⁶⁹Yb-DTPA and ¹¹¹In-DTPA in30. The results of this study were as follow.

1. ¹¹¹In-DTPA was chemically stable in intra-thecal administration.

2. A reactive fever was minimal with 111In-DTPA if any.

3. There was no adverse reaction, such as asepticmeningitis, following ¹¹¹In-DTPA cisternographies.

4. The effective half-life of ¹¹¹In-DTPA was 16hours, and that of ¹⁶⁹Yb-DTPA 22 hours in thisseries. This means the men were exposed to radio-activity less with ¹¹¹In_DTPA than with ¹⁶⁹Yb-DTPA.

5. However, there was no difference in diagnosticvalue between these two radiopharmaceuticals, even48 hours after intrathecal administration. From this study ¹¹¹In-DTPA appers to be moresuitable for RI cisternography than ¹⁶⁹Yb-DTPA.