Formetric 3D
Technical specifications
The Diers Formetric 3D is a full featured photogrammetry system using white light get a highly accurate (+/- 0.2 mm) topographical representation of a patient's back. Through rasterstereography, a map of 10,000 individual points are obtained and a surface is applied to these points. Using mathematical algorithms the apex of the prominence of C7, the left and right dimples at the Posterior Superior Iliac Spines, and the sacral prominence are automatically located. This avoids the errors associated with marker placement and repeatability in follow-up.
Speed of Scan
A scan is completed in 40 msec thus virtually eliminating the effect of body sway and thereby improving accuracy. Additionally, it is possible to take a series of 10 scans over 3 seconds and average the results. This method gives a more repeatable result as the effects of breathing and sway are factored into the result.
Radiation Safety
The Formetric 3D uses only white light and there is no radiation exposure to the patient. This is a great advantage when multiple scans are desired. Using the Formetric 3D with various protocols can isolate spinal conditions as being ascending or descending problems thus aiding in diagnosis and treatment.
Clinical Relavancy
The results are nearly instantaneous after the scan thus enabling the practitioner to utilize this tool with the patient, like a stethoscope or Doppler ultrasound device, getting results immediately to work with.
Accuracy and Repeatablity
The accuracy of the results have been verified by the digitization of nearly 500 x-rays. The results were evaluated by using a root mean square deviation. The Formetric data is a three dimensional representation and x-rays are two dimensional, both AP and lateral views were needed to do the comparison.
- The spinal midline showed a rms deviation of 1.54 mm
- Lateral and AP deviation showed a rms deviation of less than 3 mm
- Repeatability showed a rms deviation of 1.7 mm