術後分化型甲状腺癌における~（99m)TlTc-MIBIシンチグラフィの転移病巣検出能の検討~（131）I,~(201)T1との比較-

摘要

~(99m)Tc-MIBIの分化型甲状腺癌転移病巣の検出能について~(131)I,(201)T1と比較した·対象は術後分化型甲状腺癌患者40例で,転移あり25例,転移なし15例であった.陽性率は~（99m）Tc-MIBIで68%,~（131）Iで84%, ~(201)T1で60%であった.転移リンパ節の陽性率は(99m)~Tc-MIBIで56%, ~(131)Iで78%, ~(201)T1で39%,肺転移の陽性率は)~(99m)Tc-MIBIで46%,~(131)Iで82%, ~(201)T1で55%であった. ~(I31)I陰性病巣に~(201)T1 ~(99m)Tc-MIBIの集積が認められる症例の頻度は,肺,リンパ節,肝,骨,脳いずれの臓器についても30%以下であった. ~(131)Iの集積陽性群,陰性群ともに~(99n)Tc-MIBIまたは(201)~T1が集積陽性を呈する群では,陰性群と比較して血清サイログロブリン濃度が高値を示した.~(99m)Tc-MIBIでは~(201)T1同様に~(131)Iと比較して甲状腺癌転移病巣の検出能が低かったが, ~(131)Iシンチグデフイ所見が陰性でかつ血清サイログロブリン濃度が高値を示す場合は,甲状腺癌転移病巣の描画法として有用な診断法と考えられた.Detectability of metastasis in differentiated thyroid cancer using technetium-99m-methoxyisobutyl isoni-trile (~(99m)Tc-MIBI) was compared with that of ~(131)I and ~(201)T1. Forty patients after total thyroidectomy were evaluated. The scan results were compared with those of ~(131)I and ~(201)T1 whole body scintigraphy per patient. The positive rate was 68% in ~(99m)Tc-MIBI, 84% in ~(131)I, 60% in ~(201)T1 respectively. As to the lymph node metastasis, the positive rates were 56% in ~(99m)Tc-MIBI, 78% in ~(131)I, 39% in ~(201)T1. In lung metastasis, the positive rate was 46% in ~(99m)Tc-MIBI, 82% in ~(131)I and 55% in ~(201)T1.Serum thyroglobulin (Tg) was significantly higher in ~(201)T1 and/or ~(99m)Tc-MIBI positive group compared to that of negative group independent of ~(131)I scan results.Although the detectability of both ~(99m)Tc-MIBI and ~(201)T1 were inferior to that of ~(131)I, 9 to 22% of metastasis were detected only by these radiopharmaceuticals. Both ~(99m)Tc-MIBI and ~(201)T1, therefore, should be used in cases with high serum Tg even with negative ~(131)I uptake. Basing on the fact there was no prominent difference between ~(99m)Tc-MIBI and ~(201)T1 in the detectability of metastasis, ~(99m)Tc-MIBI might be more suitable tracer because of better quality image.