Biomedical Engineering Reference
In-Depth Information
Fig. 3.10
Images of a woman with a history of
breast carcinoma, now with extensive
metastatic disease throughout the spine, ribs,
and pelvis. Additional lesions can be seen in
the skull, shoulders, and proximal femurs.
Patient was administered 25 mCi
99m
Tc-hydroxymethylene diphosphonate
(
99m
Tc-HDP) and imaged 2-3 hours post
injection. Anterior and posterior whole-body
images were acquired simultaneously in
approximately 15 min with a large field of view,
dual head gamma camera. Images on left are
displayed with a linear gray scale; those on
right use a logarithmic gray scale, enhancing
the soft-tissue activity. (Courtesy Glenn J.
Hathaway, School of Nuclear Medicine,
University of Tennessee Medical Center,
Knoxville, TN.)
goes this process of electron capture (EC), going to a metastable state of the nucleus
of the daughter rhodium:
103
46
Pd +
0
-1
e →
103m
45
Rh +
0
ν.
(3.33)
The neutrino acquires the entire energy
Q
released by the reaction.
To find
Q
, we note that the captured electron releases its total mass,
m
-
E
B
,to
the nucleus when it is absorbed there,
E
B
being the mass equivalent of the binding
energy of the electron in the atomic shell. Therefore, in terms of the masses
M
Pd,N
and
M
m
Rh
,N
of the parent and daughter nuclei, the energy released by the reaction
(3.33) is given by
Q
=
M
Pd,N
+
m
-
E
B
-
M
m
Rh
,N
.
(3.34)
Since the palladium atom has one more electron than the rhodium atom, it follows
that (neglecting the small difference in the electron binding energies)
Q
is equal to
