ABSTRACT
Objective To explore the clinical value of dual-phase 99Tcm-MIBI scintigraphy in the localization and diagnosis of secondary hyperparathyroidism (SHPT).Methods A total of 20 patients (8 males,12 females; average age 49.6 years) with uremic SHPT who underwent parathyroidectomy from 2010 to 2013 were retrospectively analyzed.All patients underwent 99Tcm-MIBI SPECT/CT and 19 underwent color Doppler ultrasonography (CDUS).Post-excisional histopathology was considered as the gold standard.The diagnostic efficacies of 99Tcm-MIBI and CDUS for SHPT were calculated.The correlation between T/NT ratio in delayed imaging and the volume of excised parathyroid and the intact PTH (iPTH) were analyzed.x2 test,Pearson or Spearson correlation analysis were used to analyze the data.Results The sensitivity,specificity,positive predictive value,negative predictive value and accuracy of 99Tcm-MIBI SPECT/CT and CDUS in the diagnosis of SHPT were 66.67％ (44/66),100％(14/14),100％ (44/44),38.89％(14/ 36),72.50％ (58/80) and 78.19％(43/55),52.38％(11/21),81.13％(43/53),47.83(11/23),71.05％ (54/76),respectively.There were significant differences in specificity and positive predictive value (x2 =9.33,9.26,both P＜0.05),but no significant differences in the sensitivity,negative predictive value and accuracy (x2 =1.97,0.04,0.46,all P＞0.05).T/NT ratio correlated with serum iPTH and parathyroid volume (r=0.638,rs =0.571,both P＜0.05).Conclusions The specificity of 99Tcm-MIBI SPECT/CT is superior to CDUS in the diagnosis of SHPT.Dual-phase 99Tcm-MIBI SPECT/CT could locate the hyperfunctional parathyroid gland and provide the basis for surgical treatment.
ABSTRACT
<p><b>BACKGROUND</b>Monoclonal antibodies (mAbs) such as DD3, raised against progastrin-releasing peptide(31-98) (ProGRP (31-98)) antigen, have been used to target small cell lung cancer (SCLC). However, as an intact mAb, DD3 is cleared slowly from the body, with an optimal radioimmunoimaging time of 72 hours. More recently, a single-chain antibody fragment has demonstrated reduced excretion time in blood and normal tissues and is increasingly used in diagnostic cancer research. Thereby, it potentially increases the radioimmunoimaging efficacy. However, there have been few studies with this antibody fragment. The aim of this study was to characterize the preliminary radioimmunoimaging and biodistribution of (131)I-anti-ProGRP(31-98) scFv in nude mice bearing SCLC xenografts.</p><p><b>METHODS</b>Anti-ProGRP(31-98) scFv was used to detect ProGRP expression by flow cytometry analysis and immunohistochemistry. (131)I-anti-ProGRP(31-98) scFv was injected intravenously into healthy Kunming mice and the percentage injected dose per gram (%ID/g) in various organs was calculated. Similarly, the %ID/g and tumor/non-tumor ratio in xenograft-bearing mice was calculated. After injection of (131)I-anti-ProGRP(31-98) scFv, treated mice were imaged at 1, 24, and 30 hours. Then the tumor/base ratios were calculated.</p><p><b>RESULTS</b>ProGRP was highly expressed in NCI-H446 cells and xenograft tissue. The metabolism of (131)I-anti-ProGRP(31-98) scFv in healthy mice was consistent with a first-order and two-compartment model; T1/2α and T1/2β were 10.2 minutes and 5 hours 18 minutes, respectively. The %ID/g of (131)I-anti-ProGRP(31-98) scFv in xenografts was much higher than in healthy tissues at 12 hours after injection, reaching a maximum of (5.38±0.92) %ID/g at 24 hours. Successful imaging of xenograft tissue was achieved as early as 1 hour post-injection and persisted until 30 hours, with 24 hours proving optimal.</p><p><b>CONCLUSION</b>(131)I-anti-ProGRP(31-98) scFv shows highly selective tumor uptake with low accumulation in normal tissues and rapid blood clearance, indicating that it could be a promising agent for SCLC radioimmunoimaging.</p>