OBT OBT Equipment & Technology 2 — Questions and Answers
Question 1: What does the wavelength of an optical beam therapy device primarily determine?
- The device's battery life
- The depth of tissue penetration and tissue interaction (Correct answer)
- The loudness of the audible alert
- The color of the indicator light on the device
Correct answer: The depth of tissue penetration and tissue interaction
Wavelength determines how deeply the beam penetrates tissue and which chromophores it interacts with therapeutically.
Question 2: A beam spot size of 1 cm² with an output of 100 mW produces an irradiance of:
- 10 mW/cm²
- 100 mW/cm² (Correct answer)
- 1000 mW/cm²
- 0.1 mW/cm²
Correct answer: 100 mW/cm²
Irradiance equals power divided by area; 100 mW ÷ 1 cm² = 100 mW/cm².
Question 3: What is the purpose of an interlock system on an OBT device?
- To lock the device settings between patients
- To automatically disable beam emission when safety conditions are not met (Correct answer)
- To prevent unauthorized firmware updates
- To restrict treatment frequency to once per day
Correct answer: To automatically disable beam emission when safety conditions are not met
Interlock systems automatically cut off beam emission when safety conditions such as proper eyewear detection or door closures are not satisfied.
Question 4: Which term describes the coherence property unique to laser light compared to conventional light sources?
- Polychromatic emission
- Spatial and temporal coherence (Correct answer)
- Diffuse scattering
- Broad spectral bandwidth
Correct answer: Spatial and temporal coherence
Laser light exhibits spatial and temporal coherence, meaning all photons travel in phase in the same direction with a single wavelength.
Question 5: What is the significance of the Nominal Ocular Hazard Distance (NOHD) for an OBT device?
- The maximum treatment depth in tissue
- The minimum distance at which the beam is safe for unprotected eyes (Correct answer)
- The recommended distance between the device and power outlet
- The distance between the handpiece tip and the patient's skin
Correct answer: The minimum distance at which the beam is safe for unprotected eyes
NOHD defines the distance within which direct or specularly reflected beam exposure could cause eye injury without proper protection.
Question 6: Which device component converts electrical energy into laser light in a diode laser OBT unit?
- Photodetector module
- Semiconductor diode (laser diode) (Correct answer)
- Beam splitter prism
- Thermoelectric cooler
Correct answer: Semiconductor diode (laser diode)
In diode laser devices, semiconductor laser diodes directly convert electrical current into coherent laser light.
OBT OBT Equipment & Technology 2
What does the wavelength of an optical beam therapy device primarily determine?