Convection-enhanced delivery of [225Ac]Ac-DOTA-SP in recurrent glioblastoma – tumour uptake

A 54-year-old female with a recurrence of glioblastoma (G4,IDH-) was referred for locoregional treatment with [ 225 Ac]Ac-DOTA-SP.In an MRI scan (A1,A2) performed 1 week before TAT, the postoperative cavity volume was 12.6 cm 3 and the volume of contrast-enhanced tissue adjacent to the cavity was 4.2 cm 3 (total lesion volume 16.8 cm 3 ).The [ 225 Ac]Ac-DOTA-SP activity equal to 18.8 MBq was coinjected with 10 MBq of [ 68 Ga]Ga-DOTA-SP into the postoperative cavity.The first PET/CT (B1,B2) was acquired 15 min post-injection.Next, a 2 h slow infusion (10 l/ min) of saline was performed using a syringe pump.The second PET/CT (C1,C2) was acquired 3 h post-injection.Additionally, quantitative SPECT/CT imaging (D1,D2) was performed 5 days post-injection (20% energy windows centered over the two photopeaks: 440 and 218 keV, plus 10% lower and upper windows for scatter correction, 128 128 matrix, 128 projections, 30 s per projection, reconstruction and calibration method described in [4]).