A prospective intra-individual comparison of [68Ga]Ga-PSMA-11 PET/CT, [68Ga]Ga-NODAGAZOL PET/CT, and [99mTc]Tc-MDP bone scintigraphy for radionuclide imaging of prostate cancer skeletal metastases.

PURPOSE: Prostate cancer (PCa) commonly metastasizes to the bones. There are several radionuclide techniques for imaging PCa skeletal metastases. We aimed to compare the lesion detection rate of [68Ga]Ga-PSMA-11 PET/CT, [68Ga]Ga-NODAGA-zoledronate ([68Ga]Ga-NODAGAZOL) PET/CT, and [99mTc]Tc-MDP bone scan in the assessment of bone metastases in patients with advanced PCa. METHODS: We prospectively recruited two cohorts of patients (staging and re-staging cohorts) with advanced prostate cancer. The staging cohort was treatment-naïve PCa patients who showed skeletal metastases on bone scan. These patients were subsequently imaged with [68Ga]Ga-PSMA-11 PET/CT and [68Ga]Ga-NODAGAZOL PET/CT. Re-staging cohort was patients who were previously treated with PSMA-based radioligand therapy and were experiencing PSA progression. The re-staging cohort was imaged with [68Ga]Ga-PSMA-11 PET/CT and [68Ga]Ga-NODAGAZOL PET/CT. We performed a per-patient and per-lesion analysis of skeletal metastases in both cohorts and made a comparison between scan findings. RESULTS: Eighteen patients were included with a median age of 68 years (range = 48-80) and a median Gleason score of 8. There were ten patients in the staging cohort with a median PSA of 119.26 ng/mL (range = 4.63-18,948.00) and eight patients in the re-staging cohort with a median PSA of 48.56 ng/mL (range = 6.51-3175.00). In the staging cohort, skeletal metastases detected by [68Ga]Ga-PSMA-11 PET/CT, [68Ga]Ga-NODAGAZOL PET/CT, and bone scan were 322, 288, and 261, respectively, p = 0.578. In the re-staging cohort, [68Ga]Ga-PSMA-11 PET/CT and [68Ga]Ga-NODAGAZOL PET/CT detected 152 and 191 skeletal metastases, respectively, p = 0.529. In two patients with negative [68Ga]Ga-PSMA-11 PET/CT findings, [68Ga]Ga-NODAGAZOL detected one skeletal metastasis in one patient and 12 skeletal metastases in the other. CONCLUSION: In patients with advanced prostate cancer, [68Ga]Ga-PSMA-11 PET/CT may detect more lesions than [68Ga]Ga-NODAGAZOL PET/CT and [99mTc]Tc-MDP bone scan for the staging of skeletal metastases. In patients who experience PSA progression on PSMA-based radioligand therapy, [68Ga]Ga-NODAGA PET/CT is a more suitable imaging modality for the detection of skeletal lesions not expressing PSMA. In the setting of re-staging, [68Ga]Ga-NODAGAZOL PET/CT may detect more lesions than [68Ga]Ga-PSMA-11 PET/CT.

Single Photon Emission Tomography in the Diagnostic Assessment of Cardiac and Vascular Infectious Diseases.

Cardiac and vascular infection is an arising cause of mortality and morbidity in the adult population. Diagnosis based on culture and anatomic imaging are frequently inconclusive. Radiolabeled leucocyte scintigraphy plays a useful role in the diagnosis and management of these serious infectious conditions. In this paper, we present an update on the diagnostic performance of single- photon emission tomographic (SPECT) techniques using different radionuclides in the management of patients with cardiac and vascular infections. We performed a thorough search of recent literature on the topic. We present a discussion on the clinical utility of different SPECT tracers in cardiac and vascular infections, including infective endocarditis, cardiac implantable electronic device (CIED) infections, left ventricular assist device infection, and vascular graft infection. Radionuclide technique using SPECT tracers is a useful imaging modality in the diagnosis of cardiac infection. Among the different SPECT tracers for infection imaging, radiolabeled leucocyte scintigraphy is currently the most useful tool in the diagnosis and management of patients with suspected cardiac and vascular infection. Radiolabeled leucocyte scintigraphy has a high specificity, a result of the ability of the leucocytes to accumulate as sites of pyogenic infection but not at sites of sterile inflammation such as seen in the early post-operative period or in response to the presence of a prosthetic cardiac or vascular material. Limited experience with radiotracers for in vivo labelling of leucocytes such as 99mTc-sulesomab and 99mTc-besilesomab show acceptable diagnostic performance without the need for the tedious process of ex-vivo labeling. 67Ga scintigraphy used to be popular for cardiac and vascular infection imaging. Its use has run out of favor following the availability of more effective molecular imaging methods. SPECT techniques with radiolabeled leucocyte scintigraphy has a high diagnostic performance in the evaluation of patients with suspected cardiac or vascular infection. It is able to confirm or reject the presence of infection when results of anatomic imaging or culture remain inconclusive. Its diagnostic performance is not compromised by sterile inflammation occurring in the early post-operative period or in response to implanted prosthetic materials.