RET-Targeted Molecular Imaging Probes in Prostate Cancer

The goal of this observational diagnostic imaging study is to evaluate the value of RET-targeted PET/CT molecular imaging in diagnosing neuroendocrine prostate cancer (NEPC) and in assessing disease activity, treatment response, and prognosis. The study population consists of men aged 45-80 years, including approximately 40 patients with suspected or confirmed NEPC (positive group) and approximately 10 patients with conventional prostatic adenocarcinoma (negative control group). The main questions it aims to answer are: Can RET-targeted PET/CT imaging accurately diagnose neuroendocrine prostate cancer, using pathology as the gold standard? Compared with PSMA PET/CT, multiparametric MRI (mpMRI), and serum markers, does RET-targeted PET/CT provide better diagnostic performance (sensitivity, specificity, positive and negative predictive values)? Is the level of RET tracer uptake in lesions associated with disease progression and prognosis, and can it be used for early assessment of treatment response? Researchers will compare RET-PET/CT imaging results against pathology (the primary reference standard), PSMA PET/CT, conventional contrast-enhanced MRI, and serum markers to determine the diagnostic advantage of RET-targeted imaging. Participants will: Sign a written informed consent form; Undergo whole-body PET/CT (and if needed, PET/MRI) imaging with RET- and PSMA-targeted tracers (approximately 0.15 mCi/kg injected intravenously; if a repeat scan is needed due to disease changes, it will be performed at least 1 week apart); Have blood pressure, pulse, respiration, and temperature measured before and after imaging, and liver/kidney function tests and routine blood and urine tests performed one day before and after imaging; Undergo multiparametric MRI (mpMRI); Be followed up, with any clinical symptoms or signs of discomfort during and up to two weeks after imaging recorded in detail.

Inclusion Criteria: * Male patients aged 45-80 years. * Diagnosed with conventional prostatic adenocarcinoma or neuroendocrine prostate cancer (NEPC) by clinical data, serum markers, and pathology (biopsy); patients with no other neuroendocrine tumors or related diseases and no history of acute infection or acute trauma. * Patients with newly diagnosed disease will be enrolled before receiving specific treatment (ADT, chemotherapy, second-generation androgen receptor inhibitors, etc.) whenever possible; patients with recurrent disease will be enrolled as soon as possible. * Able to cooperate in the observation of adverse events and efficacy. * Patients with suspected NEPC based on positive serum neuroendocrine markers (SYP/CHGA/NSE), or confirmed NEPC by biopsy histopathology with positive neuroendocrine marker immunohistochemistry (SYP/CHGA/NSE). * Capable of undergoing pathological examination to confirm the diagnosis; willing to provide informed consent and able to accept follow-up. * The patient or his legally authorized representative signs the written informed consent form. Exclusion Criteria: * Patients without prostate cancer. * Fever with body temperature above 38°C or clinically evident active infection that could affect the trial. * Cardiac, pulmonary, hepatic, or renal function assessed as unsuitable for the examination (e.g., organic heart disease or arrhythmia; abnormal pulmonary function such as FVC, FEV1, FEV1/FVC, DLCO, or DLCO/VA outside the normal range with ventilatory disorders; abnormal liver function with AST, ALT, or ALP more than 1 times the upper limit of the reference range; total/direct bilirubin above normal or total protein, albumin, and globulin below normal; abnormal renal function such as hematuria or proteinuria, or creatinine, urea, or uric acid above normal values). * Uncontrolled hypertension (systolic blood pressure \>160 mmHg or diastolic blood pressure \>100 mmHg). * Abnormal coagulation function (PET/CT involves venous injection; normal coagulation must be ensured). * Significant cardiovascular abnormalities (e.g., myocardial infarction, superior vena cava syndrome, grade 2 or higher heart disease before enrollment, or heart disease that increases the risk of ventricular arrhythmia as judged by the investigator). * History of arrhythmia (multifocal ventricular premature beats, bigeminy, trigeminy, or congenital long QT syndrome). * Tachycardia or uncontrolled atrial fibrillation, symptomatic or requiring treatment (CTCAE grade 3), or asymptomatic sustained tachycardia. * Presence of left bundle branch block. * Third-degree atrioventricular block or symptomatic sick sinus syndrome. * Patients who cannot complete the PET examination due to disease progression. * Patients too ill to undergo further evaluation and treatment.