System,
i.e€., one needs in principle a separate, empirically determined
“curve”, for agent carriers (particles) of every conceivable type and
energy,
So that any generality of
the RBE cuncept is
tllusory.
Thus severe
compromises must be made in order for the system to be workable at all.
Peay
Neale
Fig. 7 Schematic based on Fig. 1, indicating that,
with LLE, one can in principle f111 in completely the
“triangular area™ represented by the fanily of curves
1.
This can be done simply by appropriate
P iaStovemi OAT Ley eae
HSEF.
The
fact that
the curves can fill an trea also
indicates that an
additional varfable is involved as well as an unéxpressed continuous
That is to say,
the three-dimensional plot in, Fig. 3 is
required.
This missing variable has
been
thought to be LET, expressed as
keV um! in tissues.
{s not adequate
for
However, it has long been well appreciated that LET
the purpose.
It is clear
from the
above discussion
Fi
as
thx
OF;
ors
alt
dos
wit
Part
call
dose
thar
cs
i
st ‘
*
Teesabs
i
o
%,
aeReve atts
Face
et:
ee
nar ad
tre s
function,
Ruse wad
ile
a
shown in Fis.
choices of particle type and energy. The plot indicates
that any discrete values of RBE tnat may be derived from
the curves in Fig. 1 are arbitrary and unique to
a particular set of clrcumstances. This indicates the
need for a different approach, such as that involving the
ae eid
aoe
8 eR
ita
dot
=
Jun
Ae ee
oles re
hantah
A Ge
agi Sak dete eetee
YR CE
.
that this missing functioa is not LET,
to
tissues,
Rather,
constitute cell dose.
charactertzed as
the
in the sense of
transfer is quite specific--to
Se
the cell TCV,
to
Thus high and low-LET radiations might better be
lacge- aad small cell dose-producing radiations.
~220-
2 EOS
‘
OLEAca a
transfer of energy
Sina] ]
risk