Actinium
Pharmaceuticals’ Technology |
A
Comparison of Alpha And Beta Emitters
Use of alpha-particles as the cancer killing agents instead of beta particles
is more attractive for a combination of reasons:
• The
alpha's energy is 30 x greater than that of a beta
(typically 6 MeV versus 200 keV)
• The
electric charge is double (+2 versus -1)
• The
mass is 7,000 x heavier (4 mass units versus 1/1800)
The result being the effective range of alpha particles in tissue is
about 5 cell diameters compared with hundreds or thousands of cell
diameters
for beta particles.
As to cell killing:
• The
amount of energy dissipated per unit track length of an alpha particle
is 1000x greater than that for beta particles.
• Non-elastic
collisions cause 3x as much cell killing per unit of energy dissipated
in tissue, proportionately increasing the effectiveness of cell
killing.
• Because
the effective range for alpha particles is <5 cell diameters, the
killing is confined to tumor cells and thus collateral damage to
normal tissue
is minimized.
As
to side effects:
• The
short penetration range and the short half-life of the therapeutic
alpha particle emitting isotopes lead to no significant effect
on normal tissues and no residual buildup of radiation in
the body resulting in a far greater overall health benefit and improved
quality of life.
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