Biomedical Engineering Reference
In-Depth Information
16.14
Problems
1.
What is reference man and what is his role in internal
dosimetry?
2.
The annual limit on intake for
32
Pbyingestionis8
10
6
Bq.
What is the committed effective dose per unit activity of
ingested
32
P?
×
The ALI for inhalation of
235
U aerosols having retention times
of the order of weeks in the pulmonary region is
1
3.
10
4
Bq.
What is the corresponding derived air concentration?
×
A single inhalation of 10
6
Bq of a certain radionuclide results
in a committed effective dose of 6.1 mSv.
(a)
4.
What is the ALI?
(b)
What is the DAC?
5.
In what ways is the limitation of the annual effective dose
different for external and internal radiation when the ALI
concept is applied?
10
3
Bq of a
radionuclide, a certain organ of the body will receive doses of
0.20 mGy from low-energy beta particles and 0.05 mGy from
alpha particles during the next 50 y. These are the only
radiations emitted, and this organ is the only one that receives
appreciable irradiation as a result of the intake. The organ has a
weighting factor,
w
T
=
6.
As a result of the single intake of
6.3
×
0.05.
(a)
What is the committed equivalent dose to the organ?
(b)
What is the committed effective dose to the individual?
(c)
What is the ALI for this route of intake?
7.
(a)
What fraction of inhaled aerosols with an AMAD of 1
µ
m
is assumed to be deposited in the trachea and bronchial
tree in the ICRP-30 model of the respiratory system?
(b)
What fraction is exhaled?
8.
Write a differential equation, analogous to Eq. (16.3), that
describes the rate of change
q
b
(
i
)
of the activity in compartment
b of the respiratory-system model (Fig. 16.4) for a rate
I
(
t
)
of
inhalation.
Given the inhalation rate
I
(
t
)
, write two differential equations
that describe the rates of change
q
i
(
t
)
and
q
j
(
t
)
of activity in the
lymph-node compartments of the respiratory-system model in
Fig. 16.4.
9.
10.
An activity of 1000 Bq of a class-W aerosol (AMAD
=
1
µ
m) is
inhaled in a single intake.
