Effective Doses for Extremity Imaging Using Cone Beam CT Scanners
J Dave1*, T Minch2, (1) Thomas Jefferson University, Philadelphia, PA, (2) Curvebeam, Hatfield, PA
Presentations
PO-GePV-I-5 (Sunday, 7/10/2022) [Eastern Time (GMT-4)]
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Purpose: To compute effective doses (ED) associated with hand/wrist imaging and weight-bearing imaging of knees and foot/ankle using HiRise (CurveBeam, Hatfield, PA) cone beam CT (CBCT) scanner and compare with reported ED with LineUP (CurveBeam) CBCT scanner.
Methods: Customized anthropomorphic phantoms for adult hand/wrist (Model XA231P), knee (Model XA245L), and foot/ankle (Model XA241R; The Phantom Laboratory, Salem, NY) were imaged using the HiRise CBCT. The phantoms had slots to position optically stimulated luminescence dosimeters (nanoDots, Landauer, Glenwood, IL) for computing tissue doses. The manufacturer suggested protocols were used for imaging of hand/wrist (kV:120, mA:5.5, pulse duration:12 ms, frames:480), knee (kV:130, mA:6.5, pulse duration:15 and 25 ms, frames:720 frames), and foot/ankle (kV:120, mA:5.5, pulse duration:12 ms, frames:720 frames and kV:130, mA:6.5, pulse duration:15 ms, frames:720) phantoms. Screened nanoDots were used to compute average tissue-absorbed doses based on 10 acquisitions, and then utilizing the fraction of tissue irradiated and 2007 ICRP tissue weighting factors ED were computed. These ED were compared to previously reported values for the LineUP CBCT based on imaging the same phantoms. For LineUP CBCT, the acquisition protocol utilized 120 or 100 kV (standard or “Lite” protocol), with a pulse duration of 12 ms, 5 mA and 482 frames.
Results: The ED associated with the HiRise CBCT were 1.6 μSv for hand/wrist protocol, 4.0 and 6.8 μSv for knee protocols, and 4.8 and 6.8 μSv for foot/ankle protocols. For the LineUP CBCT, the reported ED ranged from 0.3 to 3.2 μSv. There was a statistically significant increase in the ED associated with the HiRise CBCT compared to LineUP CBCT (p=0.001).
Conclusion: The ED associated with hand/wrist imaging and weight-bearing imaging of knees and foot/ankle using HiRise CBCT were higher than LineUP CBCT; these ED values (max:6.8 μSv) are still negligible and therefore, imaging should be based on clinical applicability.
Funding Support, Disclosures, and Conflict of Interest: JD: Medical physicist consulting agreement with Rayscan Inc (NJ); Research consulting with CurveBeam; Research support from Philips Healthcare; Contrast agent support from Lantheus Medical Imaging and GE Healthcare; TM: Employee of CurveBeam
Keywords
Skeletal Radiography, Dosimetry, Cone-beam CT
Taxonomy
IM- Cone Beam CT: Radiation dosimetry & risk
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