Imaging Characteristics of Different ⁶⁸Ga-PSMA Probes in Prostate Cancer

Inclusion Criteria:

1. The subject has fully understood the trial content, process, and potential risks, and has voluntarily signed the informed consent form;
2. Male subjects aged ≥ 18 years;
3. Clinically or radiologically assessed as metastatic hormone-sensitive prostate cancer (mHSPC) or metastatic castration-resistant prostate cancer (mCRPC);
4. Eastern Cooperative Oncology Group (ECOG) performance status score of 0-2;
5. Presence of positive lesions on ⁶⁸Ga-PSMA-11 PET/CT scan;
6. Blood routine, renal function, and liver function tests meeting the following criteria:

   1. Platelet count \> 90 × 10⁹/L;
   2. Urea/urea nitrogen and serum creatinine \< 1.5 × upper limit of normal (ULN);
   3. Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) \< 2.5 × ULN;
7. Expected survival time ≥ 6 months;
8. From the date of signing the informed consent form until 3 months after administration, the subject and his partner must use effective contraceptive measures, and the subject must avoid sperm donation.

Exclusion Criteria:

1. Having participated in another interventional clinical trial prior to signing the informed consent form and being within 5 half-lives of the investigational product of that trial; or currently participating in another interventional clinical trial; or having participated in a clinical trial involving radiopharmaceuticals prior to signing the informed consent form with an interval of less than 3 months between the last dose and the informed consent signing date.
2. Having received any intravenous iodine-containing contrast agent within 24 hours prior to administration, or any high-density oral contrast agent (e.g., barium sulfate) within 5 days prior to administration. Oral water-soluble contrast agents (e.g., compound meglumine diatrizoate oral solution) are acceptable.
3. Having received high-energy γ-ray-emitting agents (\>300 KeV, e.g., radiopharmaceuticals labeled with radionuclides such as \[¹³¹I\]I, \[¹⁸F\]F, \[⁶⁸Ga\]Ga, \[⁶⁴Cu\]Cu, etc.) within a period equivalent to either 5 half-lives of the agent or 2 days, whichever is longer, prior to administration.
4. Planning to adjust anti-tumor medication during the study period.
5. Being unable to complete the required PET/CT imaging procedures.
6. Having any medical condition or other circumstances that, in the investigator's judgment, may affect the safety or compliance of the subject.