Institutional patient dose levels in multislice computed tomography examinations

• Κύριος συγγραφέας: Μόκα, Άλκηστη
• Άλλοι συγγραφείς: Παναγιωτάκης, Γεώργιος
• Μορφή: Thesis
• Γλώσσα: English
• Έκδοση: 2017
• Θέματα: Computed tomography; Institutional doses; Υπολογιστική τομογραφία; Δόση ασθενών; 616.075 722

Computed tomography (CT) is a major source of radiation patient dose from medical exposure. During the last years CT examinations have increased a lot, so there is need for optimization of the patient dose. In this study the institutional doses for CT examinations for head, chest, abdomen and chest/abdomen, in the University Hospital of Patras are presented. The systems that have been used were Toshiba Aquilion Prime (80 slices) and General Electric Lightspeed 16 (16 slices). Totally four hundred patients participated in this study, fifty of each examination and system. Τhe patient characteristics (age, sex, body mass index (BMI)) were recorded. To calculate the patient dose the dose index utilized was CTDIvol and DLP. The 75th percentile of DLP distribution was calculated for comparison purposes. For Toshiba CT scanner the 75th percentile of CTDIvol values in head, chest, abdomen and chest /abdomen examinations were 54.7 mGy, 3.8 mGy, 7 mGy and 10.9 mGy, whilst the DLP values were 959 mGy*cm, 150.9 mGy*cm, 314.5 mGy*cm and 612.2 mGy*cm, respectively. For GE scanner the corresponding CTDIvol values were 110.4/58.6 mGy (post fossa/cerebrum), 11.9 mGy, 14.7 mGy and 13 mGy, whilst the DLP values were 447.7/713.3 mGy*cm (post fossa/cerebrum), 416.7 mGy*cm, 636.2 mGy*cm and 758.1 mGy*cm, respectively. In addition, the relation of body mass index (BMI) with radiation dose was investigated, and showed a linear-like analogy between the two parameters in all body examinations. In head examination the dose values tend to create a horizontal form. A further categorization of the patients can be possible. Finally, the 75th percentile of CTDIvol and DLP values of each examination were compared with the national and international DRLs. The corresponding values from Toshiba scanner were lower than national and international recommended DRLs. For GE scanner these values were comparable with the corresponding from other countries in all examinations.