Summary:
The evolution of interventional radiology has designated as an alternative
option that replaces open surgery. The main disadvantage of interventional
radiology practices is the usage of ionizing radiation, in order to visualize
the region of interest, resulting in the necessity of optimization in the
practices to reduce the potential risk as the absorbed dose can be
significantly higher than normal radiographic examinations. Percutaneous
transhepatic billiary drainage – PTBD, chemoembolizations, diagnostic
subtracted angiography (DSA) of abdominal aorta to lower libs are
interventional practices that the patients’ radiation burden is in high levels.
The main purpose of this thesis is the dosimetric study of the above referred
interventional procedures. The used dosimetric parameters were DAP, equivalent
organ doses HT, effective dose E, organ dose and effective dose conversion
factors and the risk of exposure-induced cancer death (REID). Doses and
conversion factors were calculated simulating the interventional procedures
with Monte Carlo codes. The used Monte Carlo codes were MCNP5 and PCXMC2.0.
There were used two codes in order to increase the accuracy of the calculations.
The mean DAP values of the male (n=20) and female (n=23) group that underwent
in PTC were 4500±2600 και 5500±3300 cGycm2, respectively. The effective dose
conversion factors were 1,1 10-3 and 1,2 10-3 for both group calculated with
MCNP5 and PCXMC2.0 codes, respectively. The mean calculated REID% values were
0,015±0,013 και 0,022±0,016, for the group of males and female, respectively.
The mean DAP of the group underwent in chemoembolization (n=32) was 8360 ± 5530
cGycm2, the mean calculated REID% value was 0,052±0,036 and the effective dose
conversion factors were ήταν 1,4 10-2 και 1,6 10-2 calculated with MCNP5 and
PCXMC2.0 codes, respectively. The mean DAP of the group underwent in DSA (n=30)
was 5075.1±2420.4 cGy cm2, the mean calculated REID% was 0,016±0,0067 and the
effective dose conversion factors were ήταν 5,1 10-4 και 5,7 10-4 calculated
with MCNP5 and PCXMC2.0 codes, respectively.
The dosimetric study of complex interventional procedures contributes to
characterization of the radial risk and optimization of the used techniques
since the radiation burden is higher than the classic radiographic
examinations.
Keywords:
Dosimetry, Monte Carlo, Interventional dosimetry, Simulation, Effective dose conversion factors
