Biomedical Engineering Reference
In-Depth Information
Y-90, the perfect isotope
Half-life
64 h
100% beta
emission
Mode of decay
Maximum
beta energy
2.28 MeV
0.9367 MeV
2.5 mm
Average beta energy
Average penetration
range in soft tissue
Absorbed dose over
complete decay
50 Gy/GBq/kg
vent line
fluid source
catheter
pumping syringe
TheraSphere
dose vial
Figure 13.7 Schematic of the delivery of radioactive yttrium aluminosilicate (YAS)
glass microspheres to malignant tumors in the liver and data for the Y-90 radioiso-
tope. (Reprinted with permission from Nordion, Ottawa, Canada. Copyright (2012)
Nordion.)
the catheter, so that microspheres are now infused selectively into either
lobe of the liver and a larger fraction of the radioactive microspheres
are delivered to the specific target tumor(s) as opposed to the healthy
liver tissue [16]. A typical dose for delivering 150Gy to the whole liver
contains from four to six million glass microspheres with an initial
activity of
2500 Bq/sphere.
As of 2011, approximately 6000 patients with primary liver can-
cer have been treated with 90 YAS glass microspheres, some receiving
multiple injections as mentioned previously. Patients are treated on an
outpatient basis and side effects are minimal in most cases, so the
patients' quality of life remains high.
There has been much interest in gaining a better picture of the
distribution of the YAS microspheres within the tumor and surrounding
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