cac-dose

Study measuring dose reduction capabiltiies of the new calcium scoring technique, volume fraction calcium mass vs. traditional Agatston scoring

Phantom Set Up

Overview

• 3 measurement inserts are included for every scan
• 2 calibration inserts are also included on the endpoints for every scan
  • Useful for automatic segmentation and for calcium mass calibration
• 2 background inserts are in between the measurement and calibration inserts
  • Useful to avoid any partial volume effect from the calibration inserts (e.g. false-positives)

NOTE: To minimize partial volume effect of erroneous air surrounding the inserts, the cardiac phantom cavity is filled with putty (~ -250 HU). This putty minimizes the partial volume effect of non-anatomical air (~ -900 HU) and also loosely simulates surrounding pericoronary adipose tissue (-30 to -190 HU)

Measurement inserts

• "A": density => 0.050 mg/mm^3, diameter => 1.2 mm
• "B": density => 0.050 mg/mm^3, diameter => 3.0 mm
• "C": density => 0.050 mg/mm^3, diameter => 5.0 mm
• "D": density => 0.100 mg/mm^3, diameter => 1.2 mm
• "E": density => 0.100 mg/mm^3, diameter => 3.0 mm
• "F": density => 0.100 mg/mm^3, diameter => 5.0 mm

Calibration (endpoint) inserts

• "N": density => 0.400 mg/mm^3, diameter => 5.0 mm

Motion

• Study included all of the above inserts at 3 different beats per minute (bpm):
  • Static: 0 bpm
  • Normal: 60 bpm
  • High: 90 bpm
• This information is included in the DICOM scan name (e.g. "F_0bpm", "D_60bpm", etc.) as it cannot be determined by the DICOM header

kV & mAs

• Various tube voltages (80, 100, 120 kV) were studied
• Various tube current exposure times (10, 15, 20, 25, 30, 40, 50, 100, 150, 250 mAs) were studied

Repository Structure

• measure_cac.jl: notebook with rich visualizations for quality control cac measurements of one singular scan
• measure_cac_script.jl: notebook wtihout visualizations for complete cac measurements for one set of scans (various mAs)
• analysis.j: notebook for analyzing all of the various cac measurements across inserts and mAs
• data/*: folder containing the CSV files across the various cac measurements (measure_cac_script.jl)