Preclinical PET imaging study of lung cancer with 64CuCl2

Recent Advances in Preclinical Studies of the Theranostic Agent [64Cu]CuCl2

64Cu is gaining recognition not only for its diagnostic capabilities in nuclear medical imaging but also for its therapeutic and theranostic potential. The simultaneous β- and Auger emissions of 64Cu can be utilized to induce a therapeutic effect on cancerous lesions. The finding of the exceptional biodistribution characteristics of the radionuclide 64Cu, when administered as basic copper ions, has highlighted its potential therapeutic application in cancer treatment. Preclinical and clinical research on the effectiveness of [64Cu]CuCl2 as a theranostic radiopharmaceutical has commenced only in the past decade. Current clinical studies are increasingly demonstrating the high specificity and uptake of [64Cu]Cu2+ by malignant tissues during early cancer progression, indicating its potential for early cancer diagnosis across various organs. This short review aims to present the latest preclinical studies involving [64Cu]CuCl2, offering valuable insights for researchers planning new in vitro and in vivo studies to explore the theranostic potential of [64Cu]Cu2+.

Improvement of Crystal Identification Accuracy for Depth-of-Interaction Detector System with Peak-to-Charge Discrimination Method

In positron emission tomography (PET), parallax errors degrade spatial resolution. The depth of interaction (DOI) information provides the position in the depth of the scintillator interacting with the γ-rays, thus reducing parallax errors. A previous study developed a Peak-to-Charge discrimination (PQD), which can separate spontaneous alpha decay in LaBr₃:Ce. Since decay constant of GSO:Ce depends on Ce concentration, the PQD is expected to discriminate GSO:Ce scintillators with different Ce concentration. In this study, the PQD-based DOI detector system was developed, which can be processed online and implemented in PET. A detector was composed of four layers of GSO:Ce crystals and a PS-PMT. The four crystals were obtained from both the top and bottom of ingots with a nominal Ce concentration of 0.5 mol% and 1.5 mol%. The PQD was implemented on the Xilinx Zynq-7000 SoC board with 8ch Flash ADC to gain real-time processing, flexibility, and expandability. The results showed that the mean Figure of Merits in 1D between four scintillators are 1.5, 0.99, 0.91 for layers between 1st-2nd, 2nd-3rd, and 3rd-4th respectively, and the mean Error Rate in 1D between four scintillators are 3.50%, 2.96%, 13.3%, and 1.88% for layers 1, 2, 3, and 4, respectively. In addition, the introduction of the 2D PQDs resulted in the mean Figure of Merits in 2D greater than 0.9 and the mean Error Rate in 2D less than 3% in all layers.

Evaluation of fluorine-18-fluorodeoxyglucose PET/computed tomography and human epithelial growth factor receptor 2 expression in treatment-naive patients with lung adenocarcinoma

OBJECTIVE

Human epithelial growth factor receptor 2 (HER2) is overexpressed in several types of cancers. The correlation between tumor glucose activity and HER2 expression can vary. This study is a retrospective investigation of fluorine-18-fluorodeoxyglucose PET/computed tomography (18F-FDG PET/CT) and HER2 expression status in patients with lung adenocarcinoma.

METHODS

The maximum standard uptake value (SUVmax) of 18F-FDG PET/CT was compared with the HER2 expression status in pretreated patients with lung adenocarcinoma. Moreover, clinicopathological characteristics, including age, gender, smoking, serum tumor markers, tumor location, size, stage and genetic mutation, were also evaluated in groups with different HER2 expressions. Patients' progression-free survival (PFS) and overall survival (OS) were also analyzed.

RESULTS

Ninety-six patients with HER2 expression, including 54 patients with HER2 overexpression and 30 patients without HER2 expression were enrolled in this study. The primary pulmonary lesion was single in all patients, and all lesions were FDG-avid on PET/CT. SUVmax had no significant association with HER2 expression or overexpression in lung adenocarcinoma. Moreover, elevated serum CYFRA211 levels were obviously associated with HER2 expression but not associated with HER2 overexpression. There were no significant differences in other clinicopathological characteristics in groups with different HER2 expressions. Furthermore, multivariate Cox regression analysis revealed that SUVmax, HER2 expression and tumor node metastasis stage were independent predictors of PFS, and SUVmax, CYFRA211 and epidermal growth factor receptor mutation were independent predictors of OS.

CONCLUSION

SUVmax had no significant association with the HER2 expression status in lung adenocarcinoma. 18F-FDG PET/CT and HER2 expression could provide valuable prognostic information for treatment-naive patients with lung adenocarcinoma.

Recent Advances in Cancer Imaging with 64CuCl2 PET/CT

Copper is required for cancer cell proliferation and tumor angiogenesis. Radioactive copper-64 chloride (⁶⁴CuCl₂) is a useful radiotracer for cancer imaging with position emission tomography (PET) based on increased cellular uptake of copper mediated by human copper transporter 1 (hCtr1) expressed on cancer cell membrane. Significant progress has been made in research of using ⁶⁴CuCl₂ as a radiotracer for cancer imaging with PET. Radiation dosimetry study in humans demonstrated radiation safety of ⁶⁴CuCl₂. Recently, ⁶⁴CuCl₂ was successfully used for PET imaging of prostate cancer, bladder cancer, glioblastoma multiforme (GBM), and non-small cell lung carcinoma in humans. Based on the findings from the preclinical research studies, ⁶⁴CuCl₂ PET/CT also holds potential for diagnostic imaging of human hepatocellular carcinoma (HCC), malignant melanoma, and detection of intracranial metastasis of copper-avid tumors based on low physiological background of radioactive copper uptake in the brain. Copper-64 radionuclide emits both β⁺ and β^- particles, suggesting therapeutic potential of ⁶⁴CuCl₂ for radionuclide cancer therapy of copper-avid tumors. Recent progress in production of therapeutic copper-67 radionuclide invites clinical research in use of theranostic pair of ⁶⁴CuCl₂ and ⁶⁷CuCl₂ for cancer imaging and radionuclide therapy.