OBJECTIVETo evaluate the application of ²⁰¹TI and (99m)Tc-MIBI scintigraphy in assessment of neoadjuvant chemotherapy for osteosarcoma.

METHODSTwenty-two patients with osteosarcoma underwent both ²⁰¹TI and (99m)Tc-MIBI scintigraphy. According to tumor necrosis rate (TNR), 22 patients were classified into three groups: Group 1(necrosis less than 50%), Group 2(50% ≊ 89% necrosis) and Group 3(necrosis greater than 90%). The uptake ratio(UR) was obtained in images before and after chemotherapy. The alteration ratio(AR) and tumor necrosis ratio (TNR) were calculated.

RESULTSIn ²⁰¹Tl images,UR(pre) and UR(post) (mean ± s.d.) of Group 1 were 2.14 ± 0.67, 2.07 ± 0.71 (P>0.05); UR(pre) and UR(post)of Group 2 were 3.45 ± 1.57 and 2.02 ± 0.97 (P<0.01); UR(pre) and UR(post) of Group 3 were 3.57 ± 0.67 and 1.36 ± 0.20 (P<0.01). In (99m)Tc-MIBI images, UR(pre)and UR(post) of Group 1 were 1.66 ± 0.42 and 1.85 ± 0.70 (P>0.05); UR(pre) and UR(post) of Group 2 were 2.39 ± 1.41 and 1.68 ± 0.72 (P<0.05);UR(pre) and UR(post) of Group 3 were 2.56 ± 0.60 and 1.19 ± 0.14 (P<0.01). The AR value in (201)Tl scintigraphy was -0.03-0.72, the liner regression analysis of AR versus TNR showed a highly significant positive correlation (r=0.95). The AR value in (99m)Tc-MIBI scintigraphy was -1.21-0.64, the liner regression analysis of AR versus TNR showed a highly significant positive correlation (r=0.71). The liner regression analysis of AR in ²⁰¹TI scintigraphy versus AR in (99m)Tc-MIBI scintigraphy showed a highly significant positive correlation (r=0.70).

CONCLUSIONThe AR changes significantly after neoadjuvant chemotherapy and is positively correlated with TNR, which indicates that ²⁰¹TI- and (99m)Tc-MIBI scintigraphy can be used for evaluation of neoadjuvant chemotherapy.