A Phase I/II Study of PET/CT-Guided Biological Target Volume Delineation and Dose Optimization for Radioactive Seed Implantation Therapy in Malignant Tumors

NCT07327515 NA NOT_YET_RECRUITING

This prospective, open-label Phase I/II trial evaluates a PET/CT-guided planning strategy for radioactive seed implantation therapy in malignant solid tumors. The approach integrates metabolic information from PET/CT into brachytherapy planning to improve the accuracy of biological target volume delineation, enhance dose coverage, and support biologically informed dose delivery. Eligible participants are assigned to one of three arms: conventional CT-guided implantation, PET/CT-guided standard-dose implantation, or PET/CT-guided biologically optimized implantation. All participants undergo image-guided treatment followed by post-implant dosimetric verification and standardized clinical follow-up. Primary endpoints include technical success rate, dosimetric superiority, and 6-month local control. Secondary endpoints include dosimetric indices (D90, V100, conformity index, homogeneity index), pain relief, quality of life (EORTC QLQ-C30), treatment-related adverse events (CTCAE v5.0), progression-free survival (PFS), failure-free survival (FFS), and overall survival (OS). Exploratory analyses will evaluate associations between baseline PET metabolic parameters (SUVmax, metabolic tumor volume) and clinical outcomes, assess the feasibility of SUV-guided dose painting, and compare the performance of tumor-specific tracers (such as PSMA and FAPI) with FDG for target delineation and treatment response prediction. The central hypothesis is that PET/CT-guided planning-particularly when incorporating biological dose optimization-will achieve superior dosimetric performance and improved local control and survival outcomes compared with conventional CT-guided implantation.

Details

Lead sponsor	Li Min
Phase	NA
Status	NOT_YET_RECRUITING
Enrolment	90
Start date	2026-01
Completion	2028-06-01

Conditions

• Malignant Tumors

Interventions

• CT-Guided Radioactive Seed Implantation
• PET/CT-Guided Radioactive Seed Implantation
• PET/CT-Guided Radioactive Seed Implantation (Biological Dose Optimization)
• Tumor-Specific PET/CT-Guided Radioactive Seed Implantation (PSMA/FAPI Subgroup)

Primary outcomes

• Technical Success Rate — Within 24 hours after procedure
  Technical success is defined as post-implant dosimetry achieving D90 ≥ 90 Gy and V100 ≥ 85% without major intraoperative or immediate postoperative complications (CTCAE Grade ≥3).
• Dosimetric Superiority of PET/CT-Guided Implantation — Immediately after implantation (dosimetric verification)
  Comparison of mean D90 between PET/CT-guided and CT-guided groups. Superiority is defined as a ≥10 Gy improvement in D90 or ≥5% increase in V100 coverage.
• Local Control Rate at 6 Months — 6 months ± 2 weeks after implantation
  Local control is defined as complete response, partial response, or stable disease per RECIST 1.1 criteria at treated sites on follow-up imaging.

Countries

China