Thanks cafa, I found this table particularly interesting....

Thanks cafa, I found this table particularly interesting.  Previously I was under the impression that SIR-Spheres were "better" than Theraspheres.  This table and the accompanying commentary says otherwise:

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

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

Two types of microspheres loaded with 90Y are commercially available, one made of resin (SIR-Spheres; Sirtex Medical, Sidney, N.S.W., Australia) and an alternative made of glass (TheraSpheres, MDS Nordion, Toronto, Ont, Canada); the differences include the amount of activity contained in each microsphere and the number of microspheres injected in a single treatment (< 5 million to 10-30 million for glass and resin microspheres, respectively); however, their efficacy, toxicity and clinical outcome are similar (Table 1).

My comment -  it appears that if Sirtex are going to be penetrate the HCC market they are going to have to fight off a reasonably strong incumbent - difficult if the outcomes are similar?