Radioembolization with Yttrium-90 microspheres in hepatocellular carcinoma: Role and perspectives

Table 1 Characteristics of commercially available Yttrium-90-microspheres for transarterial radioembolization (modified from Sangro et al[72])

	SIR-Spheres1	TheraSphere2
Isotope 90Y	Attached to the surface	Incorporated into the glass matrix
Half-life (h)	64.1	64.1
Microsphere material	Resin	Glass
Microsphere diameter (μm)	20-60	20-30
Average size (μm)	32.5	25
Approximate activity per microsphere (Bq)	50	2500
Number of microspheres per 3 GBq	40-80 × 106	1.2 × 106
Specific gravity (g/mL)	1.6	3.6
Activity per commercially available vial (GBq)	3 (can be divided)	3, 5, 7, 10, 15, 20
Activity calculation	Compartmental MIRD macrodosimetry or empirical formula based on liver volume and tumor volume	Non-compartmental MIRD macrodosimetry
Estimated dose to the central vein area (Gy) in the montecarlo simulation3	59	58
Embolic effect	Moderate	Mild
Contrast agent injection	During infusion	None
Indication	United States (FDA PMA): colorectal liver metastases	United States (FDA HDE): hepatocellular carcinoma

¹Sirtex Medical, North Sydney, Australia;

²BTG International Canada Inc., Ottawa, Ontario, Canada;

³From Gulec et al[40]. 90Y: Yttrium-90; MIRD: Medical Internal Radiation Dosimetry; FDA: Food and Drug Administration; PMA: Pre-Market Approval; HDE: Humanitarian Device Exemption.