Validation of a Method to Measure Soft Tissue Thickness Using Near Infrared Laser Light

Validierung Der Bestimmung Der Gewebedicke Mit Hilfe Von Licht im Infrarotbereich

The study is intended to verify a newly developed method to measure the thickness of cranial soft tissue. In the study, a high-resolution MRI scan is used as ground truth for a laser scan of the forehead. The laser scan is acquired point by point with a prototype scanning unit developed at the University of Luebeck's Institute for Robotics.

The measured tissue thickness using the near-infrared scanning approach is validated against the ground truth obtained by the MRI scan. The average accuracy of the reconstruction method is then computed over all subjects from the individual study arms.

The required laser intensity and exposure time as well as the achieved measurement accuracy is evaluated with respect to the different skin types of the test subjects. Correlation between these features and the skin type according to the Fitzpatrick scale will be computed.

For 1/3 of the subjects, the laser and MRI scans are repeated after 2 and 8 weeks. The results of the scans are compared and time dependency is analysed.

Study Overview

• Status: Unknown
• Conditions: Cranial Soft Tissue
• Intervention / Treatment: Device: MRI scan; Device: Laser scan; Procedure: Dental cast creation

• Study Type: Interventional
• Enrollment (Anticipated): 25
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Germany
  • Schleswig-Holstein
    • Lübeck, Schleswig-Holstein, Germany, 23562
      • Active, not recruiting
      • Clinic for Maxillofacial Surgery of the University Hospital Schleswig-Holstein
    • Lübeck, Schleswig-Holstein, Germany, 23562
      • Recruiting
      • University of Luebeck, Institute for Robotics
      • Contact: Floris Ernst, PhD; Phone Number: +494515005208; Email: ernst@rob.uni-luebeck.de
      • Principal Investigator: Floris Ernst, PhD

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• male and female adults
• variations in skin type (at least 10 subjects with skin types I & II, at least 2 subjects with skin type III, at least 3 subjects with skin type IV, at least 3 subjects with skin types V & VI)
• optional: availability of high-resolution CT or CBCT (cone-beam CT) scan of the forehead

Exclusion Criteria:

• allergies or intolerances against ABS (acrylonitrile butadiene styrene), PMMA (polymethyl methacrylate) or alginate
• elevated light sensitivity of the skin
• exclusion criteria for MRI (claustrophobia, motoric disorders, tattoos, body piercings, metallic implants in the skull, epilepsy, cardiac pacemakers)

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Non-Randomized
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

4

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Skin types I and II; Volunteers classified as skin types I and II according to the Fitzpatrick Scale Procedures: dental cast creation, MRI scan, laser scan	Device: MRI scan; Acquisition of a high-resolution MRI scan (0.15 x 0.15 x 1.0 mm³) aligned with the AC-PC (anterior commissure-posterior commissure) line; Device: Laser scan; A near-infrared laser scan of the subject's forehead is acquired; Procedure: Dental cast creation; A dental cast made of PMMA (polymethyl methacrylate) of the subject's maxilla is created
Experimental: Skin type III; Volunteers classified as skin type III according to the Fitzpatrick Scale Procedures: dental cast creation, MRI scan, laser scan	Device: MRI scan; Acquisition of a high-resolution MRI scan (0.15 x 0.15 x 1.0 mm³) aligned with the AC-PC (anterior commissure-posterior commissure) line; Device: Laser scan; A near-infrared laser scan of the subject's forehead is acquired; Procedure: Dental cast creation; A dental cast made of PMMA (polymethyl methacrylate) of the subject's maxilla is created
Experimental: Skin type IV; Volunteers classified as skin type IV according to the Fitzpatrick Scale Procedures: dental cast creation, MRI scan, laser scan	Device: MRI scan; Acquisition of a high-resolution MRI scan (0.15 x 0.15 x 1.0 mm³) aligned with the AC-PC (anterior commissure-posterior commissure) line; Device: Laser scan; A near-infrared laser scan of the subject's forehead is acquired; Procedure: Dental cast creation; A dental cast made of PMMA (polymethyl methacrylate) of the subject's maxilla is created
Experimental: Skin types V and VI; Volunteers classified as skin types V and VI according to the Fitzpatrick Scale Procedures: dental cast creation, MRI scan, laser scan	Device: MRI scan; Acquisition of a high-resolution MRI scan (0.15 x 0.15 x 1.0 mm³) aligned with the AC-PC (anterior commissure-posterior commissure) line; Device: Laser scan; A near-infrared laser scan of the subject's forehead is acquired; Procedure: Dental cast creation; A dental cast made of PMMA (polymethyl methacrylate) of the subject's maxilla is created

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Average accuracy of tissue thickness measurement method [mm]	up to 6 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
System dependency on skin color - required intensity	Correlation between skin types (according to the Fitzpatrick scale) and the outcome (required laser intensity [mW])	up to 6 months
Long-term stability of measured features - accuracy	Change in measurement accuracy [mm]	up to 8 months
Long-term stability of measured features - required intensity	Change in required laser intensity [mW]	up to 8 months
Long-term stability of measured features - required exposure time	Change in required exposure time [ms]	up to 8 months
System dependency on skin color - accuracy	Correlation between skin types (according to the Fitzpatrick scale) and the outcome (accuracy of tissue thickness measurement [mm])	up to 6 months
System dependency on skin color - exposure time	Correlation between skin types (according to the Fitzpatrick scale) and the outcome (required exposure time [ms])	up to 6 months

Collaborators and Investigators

• Sponsor: Dr. Floris Ernst
• Collaborators: University of Luebeck; Varian Medical Systems
• Investigators: Principal Investigator: Floris Ernst, PhD, University of Luebeck

Publications and helpful links

General Publications

• Wissel T, Bruder R, Schweikard A, Ernst F. Estimating soft tissue thickness from light-tissue interactions--a simulation study. Biomed Opt Express. 2013 Jun 14;4(7):1176-87. doi: 10.1364/BOE.4.001176. Print 2013 Jul 1.

Helpful Links

• Related Info

Study record dates

Study Major Dates

• Study Start: September 1, 2013
• Primary Completion (Anticipated): December 1, 2014
• Study Completion (Anticipated): February 1, 2015

Study Registration Dates

• First Submitted: August 12, 2013
• First Submitted That Met QC Criteria: August 15, 2013
• First Posted (Estimate): August 16, 2013

Study Record Updates

• Last Update Posted (Estimate): August 21, 2014
• Last Update Submitted That Met QC Criteria: August 20, 2014
• Last Verified: August 1, 2014

More Information

Terms related to this study

• Keywords: Patient; radiation; therapy; localisation; in cranial; thickness of
• Other Study ID Numbers: ROB-NIRMR-001