68Ga-DOTATATE PET–CT imaging in carotid body paragangliomas

3-[18F]Fluoro-para-hydroxyphenethylguanidine (3-[18F]pHPG) PET-A Novel Imaging Modality for Paraganglioma

Context

Functional positron emission tomography (PET) imaging for the characterization of pheochromocytoma and paraganglioma (PCC/PGL) and for detection of metastases in malignant disease, offers valuable clinical insights that can significantly guide patient treatment.

Objective

This work aimed to evaluate a novel PET radiotracer, 3-[18F]fluoro-para-hydroxyphenethylguanidine (3-[18F]pHPG), a norepinephrine analogue, for its ability to localize PCC/PGL.

Methods

3-[18F]pHPG PET/CT whole-body scans were performed on 16 patients (8 male:8 female; mean age 47.6 ± 17.6 years; range, 19-74 years) with pathologically confirmed or clinically diagnosed PCC/PGL. After intravenous administration of 304 to 475 MBq (8.2-12.8 mCi) of 3-[18F]pHPG, whole-body PET scans were performed at 90 minutes in all patients. 3-[18F]pHPG PET was interpreted for abnormal findings consistent with primary tumor or metastasis, and biodistribution in normal organs recorded. Standardized uptake value (SUV) measurements were obtained for target lesions and physiological organ distributions.

Results

3-[18F]pHPG PET showed high radiotracer uptake and trapping in primary tumors, and metastatic tumor lesions that included bone, lymph nodes, and other solid organ sites. Physiological biodistribution was universally present in salivary glands (parotid, submandibular, sublingual), thyroid, heart, liver, adrenals, kidneys, and bladder. Comparison [68Ga]DOTATATE PET/CT was available in 10 patients and in all cases showed concordant distribution. Comparison [123I]meta-iodobenzylguanidine [123I]mIBG planar scintigraphy and SPECT/CT scans were available for 4 patients, with 3-[18F]pHPG showing a greater number of metastatic lesions.

Conclusion

We found the kinetic profile of 3-[18F]pHPG PET affords high activity retention within benign and metastatic PCC/PGL. Therefore, 3-[18F]pHPG PET imaging provides a novel modality for functional imaging and staging of malignant paraganglioma with advantages of high lesion affinity, whole-body coregistered computed tomography, and rapid same-day imaging.

Drug conjugates for the treatment of lung cancer: from drug discovery to clinical practice

A drug conjugate consists of a cytotoxic drug bound via a linker to a targeted ligand, allowing the targeted delivery of the drug to one or more tumor sites. This approach simultaneously reduces drug toxicity and increases efficacy, with a powerful combination of efficient killing and precise targeting. Antibody‒drug conjugates (ADCs) are the best-known type of drug conjugate, combining the specificity of antibodies with the cytotoxicity of chemotherapeutic drugs to reduce adverse reactions by preferentially targeting the payload to the tumor. The structure of ADCs has also provided inspiration for the development of additional drug conjugates. In recent years, drug conjugates such as ADCs, peptide‒drug conjugates (PDCs) and radionuclide drug conjugates (RDCs) have been approved by the Food and Drug Administration (FDA). The scope and application of drug conjugates have been expanding, including combination therapy and precise drug delivery, and a variety of new conjugation technology concepts have emerged. Additionally, new conjugation technology-based drugs have been developed in industry. In addition to chemotherapy, targeted therapy and immunotherapy, drug conjugate therapy has undergone continuous development and made significant progress in treating lung cancer in recent years, offering a promising strategy for the treatment of this disease. In this review, we discuss recent advances in the use of drug conjugates for lung cancer treatment, including structure-based drug design, mechanisms of action, clinical trials, and side effects. Furthermore, challenges, potential approaches and future prospects are presented.

Is Nuclear Imaging Important in the Management of Head and Neck Paragangliomas?

Nuclear medical imaging is indicated in most, but not all, patients with suspected paragangliomas of the head and neck. Advances in technology and somatostatin receptor analogs have improved the selectivity and sensitivity of this imaging.

Heterogeneous Head and Neck Paraganglioma With Distinct Features on 123 I-MIBG and 68 Ga-DOTATATE Images

ABSTRACT

A 37-year-old man has palpable bilateral carotid body paragangliomas, larger on the right. The right-sided tumor is avid on both 123 I-MIBG and 68 Ga-DOTATATE PET/CT images. The left-sided tumor is only avid on 68 Ga-DOTATATE PET/CT, but not 123 I-MIBG scan. This case illustrates the heterogeneous features of carotid body paragangliomas.

Bone Metastasis of Glomus Caroticum Demonstrated on 68Ga-DOTATATE PET/CT

ABSTRACT

A 71-year-old man who was diagnosed with carotid body paraganglioma was referred to 68Ga-DOTATATE PET/CT for primary evaluation, which revealed unknown bony metastasis with intense 68Ga-DOTATATE uptake. Head and neck paragangliomas are rare neuroendocrine tumors, with a 10% of malignancy rate, and identification of metastatic sites is important in staging and prognosis of the disease. We aimed to highlight the impact of 68Ga-DOTATATE PET/CT on patient management, especially for equivocal lesions, as in our case.

68Ga-DOTATATE Uptake in an Endolymphatic Sac Tumor: Radiologic-Pathologic Correlation

After dedicated CT and MRI, Ga-DOTATATE PET/CT was performed in a patient with a temporal bone mass with primary diagnostic considerations of an endolymphatic sac tumor versus a glomus jugulotympanicum paraganglioma. The Ga-DOTATATE PET showed mild radiotracer uptake in the mass (SUVmax, 10.9). After surgical resection, pathology revealed an endolymphatic sac tumor. Immunohistochemical staining demonstrated somatostatin receptor type 2A expression in the vasculature of the mass, but not in the tumor cells.

Activities for the Development of Targeted Radionuclide Therapy in Japan

Targeted radionuclide therapy (TRT) is unique because of its efficacy and its theranostic feature in the era of precision medicine. So far, introduction of new TRT has not been going well in Japan due to several reasons including strict regulations, shortage of facilities for TRT, and insufficient reimbursement for TRT in clinic. Japanese community had several strategies to develop TRT in these 10 years, including the establishment of the National Conference for Nuclear Medicine Theranostics in which physicians, scientists, patients, people supporting patients, and industrial people gather. To promote TRT with supports from the government, the preparatory committee for the establishment of Japan Foundation of Medical Isotope Development (JAFMID) was launched. I would like to call TRT "Precision Nuclear Medicine." When we can add genomic information here, we can put it to new stage of cancer therapy. It is time for us.