Introduction: X-ray imaging is a process where the desired organ or part of the body is
shown using ionizing radiation or X-rays. Ionizing radiation can cause harmful effects on
the health of the exposed person, therefore we use various methods to reduce the received
radiation dose. Purpose: With this diploma thesis, we want to find out how the change of
tube voltage and use of additional filtration of aluminum and copper, affects the patient's
dose when imaging the lungs in two projections. Methods: We performed PA lung imaging
and lateral projection with the inherent X-ray tube filtration, after which additional copper
and aluminum filters were added. The product of dose and surface area of the image field
(DAP) was measured. Also, we calculated the effective dose and the dose to the organs with
the PCXMC 2.0 program, which uses the Monte Carlo simulation. This was done in order
to determine if there are any relations between the DAP and the effective dose and the dose
to the organs. Results: Based on the measurement results, we found that DAP also increases
by increaseing the tube voltage. We also found that as the thickness of the additional copper
filtration increases, DAP decreases, while the dose to the organs increases. The contribution
to the effective dose is also increased. The lungs, esophagus, adrenal glands, and spleen
receive the highest doses in the PA projection. The breast, adrenal glands and spleen receive
the highest doses in lateral projection. Meanwhile, the ovaries and testicles receive the least
dose in both projections. When calculating the contributions to the effective dose, we found
that the lungs and adrenal glands in the PA projection, and the lungs, breast, spleen and
stomach in the lateral projection contribute the most to the effective dose. Discussion and
conclusion: With the diploma thesis we proved that DAP increases by increasing the tube
voltage. We have also shown that using a greater thickness of additional filtration reduces
DAP and increases the dose to the organs. In the PA projection, ED was increased at 0,1 mm
using additional Cu filtration, while it was decreased at 0,2 mm and 0,3 mm filtration. In the
lateral projection, however, it increased at 0,1 mm and 0,2 mm, but did not change
significantly at 0,3 mm. In the lateral projection, DAP and the dose on the organs increase.
Given the measurement data, we can conclude that the use of additional filtration would
make sense, with regard to the radiation dose received by the patient.
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