Measurement Profiles of Nanoscale Ion Beam for Optimized Radiation Energy Losses - Atomic Nanoscale Technology in the Nuclear Industry - page 81

are.insuficient.basic.data.to.allow.the.desired.accuracy.for.dosimetry.in.all.
situations,.the.protocol.is.intended.to.serve.as.a.resource.for.standardization.
of.such.dosimetry.
It. is. useful. to. determine. the. absorbed. dose. based. on. knowledge. of. the.
types.of.charged.particles.in.heavy.charged-particle.beams..In.the.proposed.
equation,.the.luence.spectra.and.the.stopping.power,. S, of.the.absorber.mate-
rial.at.the.point.of.interest.are.used..The.energy.of.the.particles.is.denoted.
by. E .and.delta.ray.equilibrium..The.dose.in.a.small.mass. m .inside.a.homo-
geneous.medium.is.given.in.Equation.(7.2).(Rubach.and.Bichsel.1982a,.1982b,.
1982c),

n

∞

∑

( )

∫

( ) ( )

. D = Φ E S E ρ dE . (7.2)

m i

i

0

i =1

where. i is. an. index. to. sum. over. the. different. types. of. contributing. par-
ticles,.(the.mass.stopping.power.is.the.Kerma.factor.for.charged.particles)..
Additionally,.a.dosimeter.can.be.based.on.a.luence.measurement.made.in.
a.charged-particle.beam..The.total.luence.can.be.measured.with.a.Faraday.
cup. (Brown. and. Tautfest. 1956),. which. is. a. well-insulated,. conductive.
absorber. thick. enough. to. stop. all. the. primaries. and. charged. secondaries.
in. a. particle. beam,. allowing. a. measurement. of. the. beam. current.. Using.
the.Faraday.cup,.the.number,. N , of.primary.particles.of.known.energy.per.
monitor.unit.(charge.collected.on.the.transmission.ionization.chamber).is.
obtained..The.Faraday.cup.can.be.replaced.by.a.small.ionization.chamber,.
which.will.then.collect.a.charge. Q per.monitor.unit.at.the.point.of.interest..
Finally,.parameters.required.for.dose.calculation.are.the.stopping.power.of.
the.charged.particles.of.this.energy.in.muscle.tissue.as.well.as.the.effective.
area. of. the. beam.. The. dose. determination. in. gray. (Gy). is. outlined. in. the.
Equation.(7.3).

N
a

( )

( )

1 602 10 10

−

D

t =

S / ρ . × . (7.3)

.

where.( S/ ρ).is.the.mass.stopping.power.of.charged.particles.of.this.energy.in.
muscle.tissue.in.units.of.MeV.cm 2 g −1 .and. a is.the.effective.area.of.the.beam.
(cm 2 ).

7.4 Conclusions
The.protocol.is.constructed.using.the.simulation.results.in.Figure 7.6.where.a.
procedure.for.a.better.type.of.therapy.is.proposed..Empirical.measurements.