Intraoperative 2D C-arm and 3D O-arm in children: a comparative phantom study

Area of Science:

• Medical Imaging
• Radiation Oncology
• Pediatric Radiology

Background:

• Intraoperative imaging in children raises concerns regarding ionizing radiation exposure.
• Assessing radiation doses from different imaging modalities is crucial for patient safety.

Purpose of the Study:

• To compare radiation exposure in pediatric patients undergoing intraoperative imaging using 2D C-arm versus 3D O-arm systems.
• To evaluate absorbed organ doses and skin entrance dose rates.

Main Methods:

• Organ doses were measured in an anthropomorphic phantom simulating a five-year-old child using thermoluminescent dosimeters.
• Radiation exposure was assessed using a C-arm for one minute of fluoroscopy and an O-arm for a single cone-beam acquisition centered on the pelvis.
• Direct and scattered radiation doses, as well as skin entrance dose rates, were measured and compared.

Main Results:

• Absorbed doses to pelvic organs were higher with the O-arm (631.22–1691.87 µGy) compared to the C-arm (214.08–737.51 µGy), though not statistically significant (p=0.07).
• Scattered radiation doses to abdominal organs showed similar trends, with higher doses for the O-arm (25.11–114.85 µGy) versus the C-arm (8.03–55.34 µGy), also not significant (p=0.07).
• Far scattered radiation to the thorax, neck, and head was significantly higher with the O-arm (0.86–6.42 µGy) compared to the C-arm (0.04–3.08 µGy) (p=0.02).
• Skin entrance dose rate was substantially higher for the O-arm (328.58 µGy/s) than the C-arm (1.90 µGy/s).

Conclusions:

• 3D O-arm imaging of the pediatric pelvis results in higher absorbed doses than one-minute 2D C-arm fluoroscopy.
• Clinical studies are necessary to compare effective doses and fully assess the ionizing risks associated with intraoperative imaging systems in children.