Program Information
Evaluating Lens Dose Reduction in Pediatric Neuroradiology Examinations Using Automated KVp Selection Software
J Raudabaugh1,4*, A Smith1,4 , B Moore1,4 , J Ramirez Giraldo5 , G Nguyen3,4 , T Yoshizumi3,4 , (1) Duke Medical Physics, (2) Duke Radiation Oncology, (3) Duke Radiology, (4)Duke Radiation Dosimetry Laboratory, (5) Siemens Medical Solutions USA
Presentations
MO-RPM-GePD-I-3 (Monday, July 31, 2017) 3:45 PM - 4:15 PM Room: Imaging ePoster Lounge
Purpose: The purpose of this study was to evaluate the potential of an automated kVp selection software (Auto-kV) to reduce dose to the lens of the eye by physical measurements using MOSFET detectors inserted in pediatric sized phantoms.
Methods: MOSFET detectors were calibrated and then placed into two anthropomorphic phantoms, representative of 1 and 5-year-old patients. These phantoms were then imaged using a routine pediatric brain scan protocol at 120 kVp as a control in a multidetector CT system (Somatom Force, Siemens). Scans were then performed using Auto-kV software (CAREkVTM, Siemens) which concurrently adapts kV and tube current according to patient size and clinical indication . The Auto-kV was operated in a kVp range including 120, 110, and 100 kVp. Dose savings were calculated by comparing the average lens dose of both eyes from the three Auto-kV scans to average dose from the 120 kVp control scan. CNR values for each setting were also calculated to assess image quality.
Results: The average lens dose from the routine brain scan without Auto-kV was 0.920.03 cGy and 0.810.03 cGy, for the 1-year-old and 5-year-old phantoms respectively. Using the Auto-kV with settings at 120 kVp, 110 kVp, and 100 kVp resulted in dose reduction of 10.2%, 18.3%, and 23.3% respectively for the 1-year old phantom, and 0.5%, 8.6%, and 17.9% respectively for the 5-year-old phantom. The CNR for all Auto-kV scans was within 11% of the control scans for the 1 year old and within 5.5% for the 5 year old.
Conclusion: Our results show that reductions in kVp, as can be accomplished with Auto-kV software, can be used to effectively decrease dose to the lens of the eye in pediatric patients. Furthermore, the CNR measurements show that changes within 120 to 100 kV do not compromise image quality.
Funding Support, Disclosures, and Conflict of Interest: This work was supported, in part, by grants from the U.S. NRC Health Physics Fellowship Grant (No. NRC-HQ-12-G-38-0022) and Siemens HealthCare
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