Multi-institutional Protocol Guidance for Pediatric Photon-counting CT

Published Online:https://doi.org/10.1148/radiol.231741

This article addresses clinical challenges of photon-counting detector (PCD) CT in pediatric patients by outlining fundamental terminology, explaining technical aspects, and providing protocol guidance for the first commercially available PCD CT scanner.

Performing CT in children comes with unique challenges such as greater degrees of patient motion, smaller and densely packed anatomy, and potential risks of radiation exposure. The technical advancements of photon-counting detector (PCD) CT enable decreased radiation dose and noise, as well as increased spatial and contrast resolution across all ages, compared with conventional energy-integrating detector CT. It is therefore valuable to review the relevant technical aspects and principles specific to protocol development on the new PCD CT platform to realize the potential benefits for this population. The purpose of this article, based on multi-institutional clinical and research experience from pediatric radiologists and medical physicists, is to provide protocol guidance for use of PCD CT in the imaging of pediatric patients.

© RSNA, 2024

References

  • 1. Taguchi K, Iwanczyk JS. Vision 20/20: Single photon counting x-ray detectors in medical imaging. Med Phys 2013;40(10):100901.
  • 2. McCollough CH, Leng S, Yu L, Fletcher JG. Dual- and Multi-Energy CT: Principles, Technical Approaches, and Clinical Applications. Radiology 2015;276(3):637–653.
  • 3. Willemink MJ, Persson M, Pourmorteza A, Pelc NJ, Fleischmann D. Photon-counting CT: Technical Principles and Clinical Prospects. Radiology 2018;289(2):293–312.
  • 4. Flohr T, Petersilka M, Henning A, Ulzheimer S, Ferda J, Schmidt B. Photon-counting CT review. Phys Med 2020;79:126–136.
  • 5. Rajendran K, Petersilka M, Henning A, et al. Full field-of-view, high-resolution, photon-counting detector CT: technical assessment and initial patient experience. Phys Med Biol 2021;66(20):205019.
  • 6. Szeles C, Soldner SA, Vydrin S, Graves J, Bale DS. CdZnTe semiconductor detectors for spectroscopic x-ray imaging. IEEE Trans Nucl Sci 2008;55(1):572–582.
  • 7. Leng S, Bruesewitz M, Tao S, et al. Photon-counting Detector CT: System Design and Clinical Applications of an Emerging Technology. RadioGraphics 2019;39(3):729–743.
  • 8. Si-Mohamed SA, Boccalini S, Lacombe H, et al. Coronary CT Angiography with Photon-counting CT: First-In-Human Results. Radiology 2022;303(2):303–313.
  • 9. Danielsson M, Persson M, Sjölin M. Photon-counting x-ray detectors for CT. Phys Med Biol 2021;66(3):03TR01.
  • 10. Duan X, Wang J, Leng S, et al. Electronic noise in CT detectors: Impact on image noise and artifacts. AJR Am J Roentgenol 2013;201(4):W626–W632.
  • 11. Booij R, van der Werf NR, Dijkshoorn ML, van der Lugt A, van Straten M. Assessment of Iodine Contrast-To-Noise Ratio in Virtual Monoenergetic Images Reconstructed from Dual-Source Energy-Integrating CT and Photon-Counting CT Data. Diagnostics (Basel) 2022;12(6):1467.
  • 12. Dunning CAS, Marsh JF Jr, Winfree T, et al. Accuracy of Nodule Volume and Airway Wall Thickness Measurement Using Low-Dose Chest CT on a Photon-Counting Detector CT Scanner. Invest Radiol 2023;58(4):283–292.
  • 13. Rajendran K, Petersilka M, Henning A, et al. First Clinical Photon-counting Detector CT System: Technical Evaluation. Radiology 2022;303(1):130–138.
  • 14. Baffour FI, Rajendran K, Glazebrook KN, et al. Ultra-high-resolution imaging of the shoulder and pelvis using photon-counting-detector CT: a feasibility study in patients. Eur Radiol 2022;32(10):7079–7086.
  • 15. Siegel MJ, Bugenhagen SM, Sanchez A, Kim S, Abadia A, Ramirez-Giraldo JC. Comparison of Radiation Dose and Image Quality of Pediatric High-Resolution Chest CT Between Photon-Counting Detector CT and Energy-Integrated Detector CT: A Matched Study. AJR Am J Roentgenol 2023;221(3):363–371.
  • 16. Horst KK, Hull NC, Thacker PG, et al. Pilot study to determine whether reduced-dose photon-counting detector chest computed tomography can reliably display Brody II score imaging findings for children with cystic fibrosis at radiation doses that approximate radiographs. Pediatr Radiol 2023;53(6):1049–1056.
  • 17. Rapp JB, Ho-Fung VM, Ramirez KI, White AM, Otero HJ, Biko DM. Dual-source computed tomography protocols for the pediatric chest - scan optimization techniques. Pediatr Radiol 2023;53(7):1248–1259.
  • 18. Esquivel A, Ferrero A, Mileto A, et al. Photon-Counting Detector CT: Key Points Radiologists Should Know. Korean J Radiol 2022;23(9):854–865.
  • 19. Kino A, Zucker EJ, Honkanen A, et al. Ultrafast pediatric chest computed tomography: comparison of free-breathing vs. breath-hold imaging with and without anesthesia in young children. Pediatr Radiol 2019;49(3):301–307.
  • 20. Tivnan P, Winant AJ, Johnston PR, et al. Thoracic CTA in infants and young children: Image quality of dual-source CT (DSCT) with high-pitch spiral scan mode (turbo flash spiral mode) with or without general anesthesia with free-breathing technique. Pediatr Pulmonol 2021;56(8):2660–2667.
  • 21. Gordic S, Morsbach F, Schmidt B, et al. Ultralow-dose chest computed tomography for pulmonary nodule detection: first performance evaluation of single energy scanning with spectral shaping. Invest Radiol 2014;49(7):465–473.
  • 22. Grunz JP, Heidenreich JF, Lennartz S, et al. Spectral Shaping Via Tin Prefiltration in Ultra-High-Resolution Photon-Counting and Energy-Integrating Detector CT of the Temporal Bone. Invest Radiol 2022;57(12):819–825.
  • 23. Rajendran K, Baffour F, Powell G, et al. Improved visualization of the wrist at lower radiation dose with photon-counting-detector CT. Skeletal Radiol 2023;52(1):23–29.
  • 24. Vivier S, Deken V, Arous Y, et al. Pediatric chest computed tomography at 100 kVp with tin filtration: comparison of image quality with 70-kVp imaging at comparable radiation dose. Pediatr Radiol 2020;50(2):188–198.
  • 25. Krauss B, Grant KL, Schmidt BT, Flohr TG. The importance of spectral separation: an assessment of dual-energy spectral separation for quantitative ability and dose efficiency. Invest Radiol 2015;50(2):114–118.
  • 26. Shapira N, Mei K, Noël PB. Spectral CT quantification stability and accuracy for pediatric patients: A phantom study. J Appl Clin Med Phys 2021;22(3):16–26.
  • 27. Yu L, Li H, Fletcher JG, McCollough CH. Automatic selection of tube potential for radiation dose reduction in CT: a general strategy. Med Phys 2010;37(1):234–243.
  • 28. Yu L, Bruesewitz MR, Thomas KB, Fletcher JG, Kofler JM, McCollough CH. Optimal tube potential for radiation dose reduction in pediatric CT: principles, clinical implementations, and pitfalls. RadioGraphics 2011;31(3):835–848.
  • 29. Papadakis AE, Perisinakis K, Damilakis J. Automatic exposure control in CT: the effect of patient size, anatomical region and prescribed modulation strength on tube current and image quality. Eur Radiol 2014;24(10):2520–2531.
  • 30. Papadakis AE, Damilakis J. Automatic Tube Current Modulation and Tube Voltage Selection in Pediatric Computed Tomography: A Phantom Study on Radiation Dose and Image Quality. Invest Radiol 2019;54(5):265–272.
  • 31. Sartoretti T, Racine D, Mergen V, et al. Quantum Iterative Reconstruction for Low-Dose Ultra-High-Resolution Photon-Counting Detector CT of the Lung. Diagnostics (Basel) 2022;12(2):522.
  • 32. Dirrichs T, Tietz E, Rüffer A, et al. Photon-counting versus Dual-Source CT of Congenital Heart Defects in Neonates and Infants: Initial Experience. Radiology 2023;307(5):e223088.
  • 33. Yu L, Leng S, McCollough CH. Dual-energy CT-based monochromatic imaging. AJR Am J Roentgenol 2012;199(5 Suppl):S9–S15.
  • 34. Siegel MJ, Ramirez-Giraldo JC. Dual-Energy CT in Children: Imaging Algorithms and Clinical Applications. Radiology 2019;291(2):286–297.
  • 35. Siegel MJ, Kaza RK, Bolus DN, et al. White Paper of the Society of Computed Body Tomography and Magnetic Resonance on Dual-Energy CT, Part 1: Technology and Terminology. J Comput Assist Tomogr 2016;40(6):841–845.
  • 36. Goo HW. Dual-energy lung perfusion and ventilation CT in children. Pediatr Radiol 2013;43(3):298–307.
  • 37. Kamps SE, Otjen JP, Stanescu AL, Mileto A, Lee EY, Phillips GS. Dual-Energy CT of Pediatric Abdominal Oncology Imaging: Private Tour of New Applications of CT Technology. AJR Am J Roentgenol 2020;214(5):967–975.
  • 38. Boccalini S, Dessouky R, Rodesch PA, et al. Gadolinium K-edge angiography with a spectral photon counting CT in atherosclerotic rabbits. Diagn Interv Imaging 2023;104(10):490–499.
  • 39. Ren L, Huber N, Rajendran K, Fletcher JG, McCollough CH, Yu L. Dual-Contrast Biphasic Liver Imaging With Iodine and Gadolinium Using Photon-Counting Detector Computed Tomography: An Exploratory Animal Study. Invest Radiol 2022;57(2):122–129.
  • 40. Jost G, McDermott M, Gutjahr R, Nowak T, Schmidt B, Pietsch H. New Contrast Media for K-Edge Imaging With Photon-Counting Detector CT. Invest Radiol 2023;58(7):515–522.
  • 41. Kumar D, Moghiseh M, Chitcholtan K, et al. LHRH conjugated gold nanoparticles assisted efficient ovarian cancer targeting evaluated via spectral photon-counting CT imaging: a proof-of-concept research. J Mater Chem B Mater Biol Med 2023;11(9):1916–1928. [Published correction appears in J Mater Chem B 2023;11(21):4820.]
  • 42. Higashigaito K, Schmid T, Puippe G, et al. CT Angiography of the Aorta: Prospective Evaluation of Individualized Low-Volume Contrast Media Protocols. Radiology 2016;280(3):960–968.
  • 43. Arslan S, Onur MR, Sarıkaya Y, Özcan HN, Haliloğlu M, Akata D. Radiation dose levels of thoracic-lumbar spine CT in pediatric trauma patients and assessment of scan parameters for dose optimization. Pediatr Radiol 2022;52(1):65–74.
  • 44. Gottumukkala RV, Kalra MK, Tabari A, Otrakji A, Gee MS. Advanced CT Techniques for Decreasing Radiation Dose, Reducing Sedation Requirements, and Optimizing Image Quality in Children. RadioGraphics 2019;39(3):709–726.
  • 45. Lira D, Padole A, Kalra MK, Singh S. Tube potential and CT radiation dose optimization. AJR Am J Roentgenol 2015;204(1):W4–W10.
  • 46. Siegel MJ, Ramirez-Giraldo JC, Hildebolt C, Bradley D, Schmidt B. Automated low-kilovoltage selection in pediatric computed tomography angiography: phantom study evaluating effects on radiation dose and image quality. Invest Radiol 2013;48(8):584–589.
  • 47. Milos RI, Röhrich S, Prayer F, et al. Ultrahigh-Resolution Photon-Counting Detector CT of the Lungs: Association of Reconstruction Kernel and Slice Thickness With Image Quality. AJR Am J Roentgenol 2023;220(5):672–680.
  • 48. Kim SH, Choi YH, Cho HH, et al. Comparison of Image Quality and Radiation Dose between High-Pitch Mode and Low-Pitch Mode Spiral Chest CT in Small Uncooperative Children: The Effect of Respiratory Rate. Eur Radiol 2016;26(4):1149–1158.
  • 49. Abadi E, McCabe C, Harrawood B, Sotoudeh-Paima S, Segars WP, Samei E. Development and Clinical Applications of a Virtual Imaging Framework for Optimizing Photon-counting CT. Proc SPIE Int Soc Opt Eng 2022;12031.
  • 50. Bette S, Decker JA, Braun FM, et al. Optimal Conspicuity of Liver Metastases in Virtual Monochromatic Imaging Reconstructions on a Novel Photon-Counting Detector CT-Effect of keV Settings and BMI. Diagnostics (Basel) 2022;12(5):1231.
  • 51. Peña JA, Klein L, Maier J, et al. Dose-efficient assessment of trabecular microstructure using ultra-high-resolution photon-counting CT. Z Med Phys 2022;32(4):403–416.
  • 52. Thomsen FSL, Horstmeier S, Niehoff JH, Peña JA, Borggrefe J. Effective Spatial Resolution of Photon Counting CT for Imaging of Trabecular Structures is Superior to Conventional Clinical CT and Similar to High Resolution Peripheral CT. Invest Radiol 2022;57(9):620–626.
  • 53. Rajagopal JR, Sahbaee P, Farhadi F, et al. A Clinically Driven Task-Based Comparison of Photon Counting and Conventional Energy Integrating CT for Soft Tissue, Vascular, and High-Resolution Tasks. IEEE Trans Radiat Plasma Med Sci 2021;5(4):588–595.
  • 54. Dunning CAS, Rajendran K, Inoue A, et al. Optimal Virtual Monoenergetic Photon Energy (keV) for Photon-Counting-Detector Computed Tomography Angiography. J Comput Assist Tomogr 2023;47(4):569–575.
  • 55. Rippel K, Decker JA, Wudy R, et al. Evaluation of run-off computed tomography angiography on a first-generation photon-counting detector CT scanner: comparison with low-kVp energy-integrating CT. Eur J Radiol 2023;158:110645.
  • 56. Romanyukha A, Folio L, Lamart S, Simon SL, Lee C. Body Size-specific Effective Dose Conversion Coefficients for CT Scans. Radiat Prot Dosimetry 2016;172(4):428–437.

Article History

Received: July 6 2023
Revision requested: Aug 30 2023
Revision received: Dec 7 2023
Accepted: Jan 3 2024
Published online: May 21 2024