Dose and image quality evaluation in paediatric radiography using Monte Carlo techniques

• Κύριος συγγραφέας: Λαδιά, Αρσενόη
• Άλλοι συγγραφείς: Παναγιωτάκης, Γεώργιος
• Μορφή: Thesis
• Γλώσσα: English
• Έκδοση: 2017
• Θέματα: Radiation dose; Paediatric radiography; Image quality; Δόση ασθενούς; Παιδιατρική ακτινογράφηση; Ποιότητα εικόνας; 618.920 075 72

Chest and abdomen radiographs are the most common examinations in paediatric radiology. Radiation protection is of particular importance in paediatric radiology. X-ray examination of children attracts particular interest, mainly due to the increased risk for the expression of delayed radiogenic cancers as they have many years of expected life remaining. It is important to ensure that patient radiation dose is kept to low level without image quality degradation. In this work, the effective dose, risk and image quality were assessed in chest and abdomen radiography. Patient data and exposure parameters were recorded during examinations of 240 patients, separated in four age groups undergoing chest or abdomen examinations, according to their anatomical characteristics. The dose and risk were estimated utilizing the PCXMC 2.0 code. The organs received the highest dose in all patient groups were liver, lungs, stomach, thyroid, pancreas, breast, spleen in chest radiographs and liver, lungs, colon, stomach and ovaries, uterus (for girls) and prostate (for boys) in abdomen radiographs. The effective dose for the chest was 4.9 – 10.7 μ Sv, while for the abdomen 21.1- 62.6 μ Sv.The mean REID value was1.254 x10-5 for the abdomen and0.645x10-5for the chest. The risk was slightly higher in the case of 1 y age group. The image quality was assessed by two radiologists based on image features provided by the CEC guidelines. Image quality values were similar for all age groups, with a slight increase in chest radiographs compared to abdomen radiographs. Improved image quality values were obtained for the processed images, for both chest and abdomen radiographs. Additionally, the influence of increased body mass index (BMI) in radiation dose and associated risk was investigated for paediatric patients aged 5 to 6.5 years, undergoing chest (64 patients) or abdomen (64 patients) radiography. Patients were categorized into normal and overweight, according to the BMI classification scheme. Entrance surface dose (ESD), organ dose, effective dose (ED) and risk of exposure induced cancer death (REID) were calculated using the Monte Carlo based code PCXMC 2.0. Statistically significant increase in patient radiation dose and REID was obtained for overweight patients as compared to normal ones, in both chest and abdomen examinations (Wilcoxon singed-rank test for paired data, p<0.001). The percentage increase in overweight as compared to normal patients of ESD, organ dose (maximum value), ED and REID was 13.6%, 24.4%, 18.9% and 20.6%, respectively, in case of chest radiographs. Corresponding values in case of abdomen radiographs were 15.0%, 24.7%, 21.8% and 19.8%, respectively. An increased BMI results in increased patient radiation dose in chest and abdomen paediatric radiography.