This study aims to evaluate a novel 5T4 targeted nanobody PET imaging tracer, 68Ga-MY, for the detection and evaluation of solid tumors.

The 5T4 oncofoetal antigen is considered a valuable tumor-associated antigen, which is expressed in many different cancers, but is rarely expressed in normal adult tissues. And cell surface expression of 5T4 is an important property for antibody-targeted therapies. It has been shown that 5T4 is expressed on tumour-initiating cells (TICs) and associated with worse clinical outcome. Moreover, decreased adherence due to 5T4 expression may be associated with cancer spread.

In this single-center, open-label, self-controlled study, approximately 20 patients with suspected or confirmed solid tumors will undergo PET/CT imaging using 68Ga-MY. The imaging results will be compared with 18F-FDG. The study will assess tracer uptake in tumor lesions and compare diagnostic performance between imaging methods. The results may help determine whether 68Ga-MY PET/CT can improve tumor detection, staging, and clinical evaluation in patients with solid tumors.

Inclusion Criteria:

1. Patients with solid tumors;
2. Presence of measurable lesions on imaging examinations;
3. Expected survival ≥12 weeks.

Exclusion Criteria:

1. Severe hepatic or renal dysfunction;
2. Women who are planning pregnancy, pregnant, or breastfeeding;
3. Unable to remain in supine position for 30 minutes;
4. Refusal to participate in this clinical study;
5. Diagnosis of claustrophobia or other psychiatric disorders;
6. Other conditions deemed by the investigator as inappropriate for participation in the trial.

In accordance with the ICMJE data-sharing guidelines and Chinese data-privacy laws, raw clinical and imaging data were not publicly available to prevent compromise of patient privacy. However, the corresponding author will share deidentified patient-level data, imaging parameters (SUV values), and study protocol details if reasonably requested by the requestor.

Data access will be granted through a secure data sharing agreement for a period of 3 years after publication.

Applicants must provide a methodologically sound research plan and obtain approval from their institutional ethics committee.