Τίτλος:
Fetal dose evaluation during breast cancer radiotherapy
Γλώσσες Τεκμηρίου:
Αγγλικά
Περίληψη:
Purpose: The aim of the work was to estimate the radiation dose
delivered to the fetus in a pregnant patient irradiated for breast
cancer.
Methods and Materials: A 45-year woman was treated for left breast
cancer using a 6 MV photon beam with two isocentric opposing tangential
unwedged fields. Daily dose was 2.3 Gy at 95% isodose line given by two
fields/day, 5 days/week. A total dose of 46 Gy was given in 20 fractions
over a 4-week period. Pregnancy confirmed during the second therapeutic
week. Treatment lasted between the second and sixth gestation week.
Radiation dose to fetus was estimated from in vivo and phantom
measurements using thermoluminescence dosimeters and an ionization
chamber. In vivo measurements were performed by inserting either a
catheter with TL dosimeters or ionization chamber into the patient’s
rectum. Phantom measurements were performed by simulating the treatment
conditions on an anthropomorphic phantom.
Results: TLD measurements (in vivo and phantom) revealed fetal dose to
be 0.085% of the tumor dose, corresponding to a cumulative fetal dose
of 3.9 cGy for the entire treatment of 46 Gy. Chamber measurements (in
vivo and phantom) revealed a fetal dose less than the TLD result: 0.079
and 0.083% of the tumor dose corresponding to cumulative fetal dose of
3.6 cGy and 3.8 cGy for in vivo and phantom measurement, respectively.
Conclusions: It was concluded that the cumulative dose delivered to the
unshielded fetus was 3.9 cGy for a 46 Gy total tumor dose. The estimated
fetal dose is low compared to the total tumor dose given due to the
early stage of pregnancy, the large distance between fundus-radiation
field, and the fact that no wedges and/or lead blocks were used. No
deterministic biological effects of radiation on the live-born embryo
are expected. The lifetime risk for radiation-induced fatal cancer is
higher than the normal incidence, but is considered as inconsequential.
(C) 1998 Elsevier Science Inc.
Συγγραφείς:
Antypas, C
Sandilos, P
Kouvaris, J
Balafouta, E
Karinou,
E
Kollaros, N
Vlahos, L
Περιοδικό:
International Journal of Radiation, Oncology, Biology, Physics
Εκδότης:
PERGAMON-ELSEVIER SCIENCE LTD
Λέξεις-κλειδιά:
fetal dose; radiation therapy; breast cancer; pregnancy
DOI:
10.1016/S0360-3016(97)00909-7
