Abstract |
Intraperitoneal adminstration of radioisotopes is
suggested to treat the metastatic ovarian cancer in the
pertioneal cavity. Administering beta-emitting
radioisotopes into the pertioneal cavity allows the
maximum energy delivery to the cancerous cells of the
pertioneal wall surface while sparing the normal cells
located in deep site of the peritoneal wall. In this
study, dose estimates of the peritoneal wall are
provided to be used for prescribing the amount of
166Ho-chitosan complex administered. The 166Ho-chitosan
complex diffused in the peritoneal fluid may attach to
the peritoneal wall surface. The attachment fraction of
166Ho-chitosan complex to the peritoneal wall surface
is obtained by simulating the ascites with Fischer
rats. Both volume source in the peritoneal fluid and
the surface source over the peritoneal wall surface are
counted for the contribution to the peritoneal wall
dose. The Monte Carlo code EGS4 is used to simulate the
energy transfer of the beta particles emitted from
166Ho. A plane geometrical model of semi-infinite
volume describes the peritoneal cavity and peritoneal
wall. A semi-infinite plane of 10 μm in thickness at
every 1 mm of depth in the peritoneal wall is taken as
the target in dose estimation. Greater han 98 percents
of attachment fraction has been observed from the
experiments with Fischer rats. Given 1.3μCi/㎠ and
2.4μCi/ml of uniform activity density, absorbed dose
is 123 Gy, 8.59 Gy, 3.00 Gy, 1.03 Gy, and 327 Gy at 0
mm, 1 mm, 2 mm, 3 mm, and 4 mm in depth to the
peritoneal wall, respectively. |