Changes of [18F]FDG-PET/CT quantitative parameters in tumor lesions by the Bayesian penalized-likelihood PET reconstruction algorithm and its influencing factors.

BACKGROUND: To compare the changes in quantitative parameters and the size and degree of 18F-fluorodeoxyglucose ([18F]FDG) uptake of malignant tumor lesions between Bayesian penalized-likelihood (BPL) and non-BPL reconstruction algorithms. METHODS: Positron emission tomography/computed tomography images of 86 malignant tumor lesions were reconstructed using the algorithms of ordered subset expectation maximization (OSEM), OSEM + time of flight (TOF), OSEM + TOF + point spread function (PSF), and BPL. [18F]FDG parameters of maximum standardized uptake value (SUVmax), SUVmean, metabolic tumor volume (MTV), total lesion glycolysis (TLG), and signal-to-background ratio (SBR) of these lesions were measured. Quantitative parameters between the different reconstruction algorithms were compared, and correlations between parameter variation and lesion size or the degree of [18F]FDG uptake were analyzed. RESULTS: After BPL reconstruction, SUVmax, SUVmean, and SBR were significantly increased, MTV was significantly decreased. The difference values of %ΔSUVmax, %ΔSUVmean, %ΔSBR, and the absolute value of %ΔMTV between BPL and OSEM + TOF were 40.00%, 38.50%, 33.60%, and 33.20%, respectively, which were significantly higher than those between BPL and OSEM + TOF + PSF. Similar results were observed in the comparison of OSEM and OSEM + TOF + PSF with BPL. The %ΔSUVmax, %ΔSUVmean, and %ΔSBR were all significantly negatively correlated with the size and degree of [18F]FDG uptake in the lesions, whereas significant positive correlations were observed for %ΔMTV and %ΔTLG. CONCLUSION: The BPL reconstruction algorithm significantly increased SUVmax, SUVmean, and SBR and decreased MTV of tumor lesions, especially in small or relatively hypometabolic lesions.

[²°¹TI and (99m)Tc-MIBI scintigraphy in evaluation of neoadjuvant chemotherapy for osteosarcoma].

OBJECTIVE: To evaluate the application of ²°¹TI and (99m)Tc-MIBI scintigraphy in assessment of neoadjuvant chemotherapy for osteosarcoma. METHODS: Twenty-two patients with osteosarcoma underwent both ²°¹TI 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. RESULTS: In ²°¹Tl 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 ²°¹TI scintigraphy versus AR in (99m)Tc-MIBI scintigraphy showed a highly significant positive correlation (r=0.70). CONCLUSION: The AR changes significantly after neoadjuvant chemotherapy and is positively correlated with TNR, which indicates that ²°¹TI- and (99m)Tc-MIBI scintigraphy can be used for evaluation of neoadjuvant chemotherapy.

[Value of (99m)Tc-MIBI/(18)F-FDG-dual-isotope simultaneous acquisition in diagnosis and treatment of myocardial infarction].

OBJECTIVE: To investigate the value of(99m)Tc-MIBI/(18)F-FDG-dual-isotope simultaneous acquisition (DISA) in diagnosis and treatment of patients with myocardial infarction. METHODS: Sixty-three patients with myocardial infarction who underwent DISA before and after treatment were enrolled in the study. All cases were divided into subgroups based on different treatment and myocardial viability: Group A1 (n = 16) with coronary revascularization and viable myocardium, A2 (n = 9) same as A1 but no viable myocardium; B1 (n = 6) with coronary revascularization + stem cell transplantation and viable myocardium, B2 (n = 7) same as B1 but no vital myocardium; C1 (n = 8) with stem cell transplantation and viable myocardium, C2 (n = 17) same as C1 but on viable myocardium. The changes of uptake rate of (99m)Tc-MIBI/(18)F-FDG before and after treatment were analyzed with SPSS 13.0 software. RESULT: There were statistical significances in DF value of (99m)Tc-MIBI or (18)F-FDG imaging before and after treatment in all groups (P <0.05), except Group A2 (P>0.05). The improvement of blood perfusion and metabolism in cardiac survival groups was more marked than that in non-cardiac survival groups after treatment (P<0.05). Furthermore, Group B1 was superior to Groups A1 and C1; Group B2 was superior to Group A2 and Group C2 (P<0.05 or<0.01). CONCLUSION: (99m)Tc-MIBI/(18)F-FDG DISA can detect myocardial viability and is of value for patients with myocardial infarction to choose appropriate therapeutic strategies. The degree of cardiac improvement after treatment can be evaluated by DISA.

[Value of thallium-201 scintigraphy in assessment of neoadjuvant chemotherapy for osteosarcoma].

OBJECTIVE: To investigate the significance of Tl-201 scintigraphy for assessment of neoadjuvant chemotherapy for osteosarcoma. METHODS: Thirty-four cases with osteosarcoma were enrolled into this study. The Tl-201 scintigraphy features including uptake ratio(UR) and size ratio(SR) were obtained in both early and delay imaging stages before and after chemotherapy. The responses of chemotherapy were classified into three grades according to the percentage of tumor necrosis in the specimens: necrosis < 50% as grade 1, necrosis of 50% approximately 90% as grade 2, diffuse necrosis > 90% as grade 3. The alteration ratio (AR) and SR were calculated according to tumor necrosis ratio (TNR). RESULTS: Of the 6 patients with grade 1 response, the mean alteration ratios were 3.19% +/- 8.40% and -26.29% +/- 63.61% in early and delay imaging stages, respectively. Among the 18 patients with grade 2 response, the mean alteration ratios were 40.07% +/- 11.95% and 39.30% +/- 9.87%, respectively. Of the 10 patients with grade 3 response, the mean alteration ratios were 78.32% +/- 8.33% and 63.26% +/- 6.06% in early and delay imaging stages, respectively. The results of liner regression analysis of TNR of the surgical specimens showed a significantly positive correlation (r = 0.71) between AR and TNR. The lesion size was reduced in 18 cases, but unchanged in 8 and increased in 8. The liner regression analysis results showed a negative correlation between SR and TNR. CONCLUSION: The alteration ratio changes significantly after neoadjuvant chemotherapy and has a significantly positive correlation with tumor necrosis ratio. Thallium-201 scintigraphy is helpful in the evaluation of neoadjuvant chemotherapy for osteosarcoma.

[Intra-operative radionuclide lymphatic mapping in sentinel lymph node biopsy of breast cancer].

OBJECTIVE: To study intra-operative radionuclide lymphatic mapping in sentinel lymph node (SLN) biopsy of breast cancer. METHODS: Forty-two breast cancer (diameter 98%, size of colloid granule 100 approximately 200 nm) was injected into the mammary tissue around the tumor or biopsy site at four points. SLN in breast cancer was detected and dissected with the help of lymphoscintigraphy and intra-operative gamma probe. Routine lymph node dissection was performed for all patients. RESULTS: The detection rate was 88.1% in lymphoscintigraphy and 97.6% in intra-operative gamma probe detection for SLN in breast cancer. The sensitivity, accuracy, false negative and specificity of SLN biopsy were 93.3% (14 in 15), 97.6% (40 in 41), 6.7% (1 in 15) and 100% (26 in 26). CONCLUSION: Sentinel lymph node in breast cancer, detected by preoperative lymphoscintigraphy combined with intra-operative gamma probe, is able to predict regional lymph node metastasis. The successful rate of SLN biopsy can be raised by improvement in the quality of nuclear imaging agent, technic of injection and method of measurement.