Caren van Roekel

125 One-day treatment in 166 Ho-radioembolization Treatment work-up Patients who were candidates for 166 Ho-radioembolization underwent triphasic contrast-enhanced abdominal CT at baseline. 166 Ho-scout activity was split according to the hepatic volume supplied by each injection position. Patients in the HEPAR I study received escalating doses of 20, 40, 60 and 80 Gy (depending on the dose cohort). All other patients received activity matching an average whole liver absorbed dose of 60 Gy, according to the following formula: ( ) = ( ( ) ∗ ( )) 50 ( ) = ( ) ( ) ( ) ( ) ⁄ ( ) = ( ) ∗ ([ ∗ ( )] + ( )) 49,670 ∗ (1 − ℎ ) ( ) = ℎ ( ) ∗ 3780 ( ) ( ) = ℎ ( ) ∗ 3780 ( ) ( ) = ( ( ) ∗ ( )) 50 ( ) ( ) = ( ( ) ∗ ( )) 16 ( ) ( ) = ( ) ∗ ([ ∗ ( )] + ℎ ℎ ( )) 49.67 ∗ (1 − ℎ ) The scout activity was approximately 250 MBq. On the 166 Ho-radioembolization treatment day, patients underwent a preparatory simulation angiography with 166 Ho-scout administration in the morning. No sedative medication was used during either angiography. In 72 patients, cone-beam CT was used to provide better visualization of the arterial supply and to assess hepatic perfusion. Standard microcatheters were used in all cases (Terumo, Progreat 2.7F), except for SIM study participants in whom both standard microcatheters and antireflux catheters were used (Surefire infusion system)(10). After administration of 166 Ho-scout, the catheters were removed while the vascular sheath remained in situ. The sheath was fixed to the skin with sterile adhesives and connected to a pressurized bag of saline for continuous flushing. Patients were transferred to the SPECT-scanner to undergo 166 Ho-SPECT/CT and were then transferred to the ward awaiting the treatment procedure. A nuclear medicine physician assessed the dose distribution and presence of extrahepatic activity. In case of relevant extrahepatic deposition (as determined in consensus between the nuclear medicine physician and the interventional radiologist), patients were excluded from treatment. Otherwise, they returned to the angio-suite in the afternoon to receive the treatment dose. Afterwards, patients had to lie supine for four hours to prevent groin bleeding. Patients received oral analgesics (paracetamol up to 4000 mg/24 h) post-treatment and were discharged within 24-48 hours after treatment. Overnight hospital stay was part of the study protocols because it allows for close monitoring of the patients. 4