Spatial Resolution Calculator - FWHM and FWTM

FWHM & FWTM Calculator

Calculate Full Width at Half Maximum (FWHM) and Full Width at Tenth Maximum (FWTM) from line profile data for nuclear medicine image quality analysis.

Peak Value
Half Maximum
Tenth Maximum

FWHM — Full Width at Half Maximum

Width (pixels)
Width (mm)

FWTM — Full Width at Tenth Maximum

Width (pixels)
Width (mm)

Line Profile Visualization

How It Works

This calculator determines FWHM and FWTM from a line profile — commonly used to assess spatial resolution in nuclear medicine imaging systems (gamma cameras, PET scanners).

  1. Enter Line Profile Data: Paste intensity values separated by spaces, commas, or new lines.
  2. Pixel Size: Enter the physical size of one pixel in mm (check your scanner/system specifications).
  3. Calculation: The tool:
    • Finds the peak intensity and its position.
    • Calculates the Half Maximum (peak / 2) and Tenth Maximum (peak / 10).
    • Uses linear interpolation to find the exact crossing points on both sides.
    • Multiplies the pixel width by the pixel size to give a physical measurement in mm.
  4. Results: FWHM and FWTM are displayed in both pixels and millimeters, with a visual chart showing the profile and reference lines.

This tool is for educational purposes only.