PAM Equipment Operation & Maintenance 2 — Questions and Answers
Question 1: When calibrating an ultrasound unit, what is the recommended method to verify that the transducer is producing acoustic output?
- Measure the cable resistance with a multimeter
- Use a BNR (beam non-uniformity ratio) test tank or radiation force balance (Correct answer)
- Apply the transducer to gel and feel for vibration
- Check the frequency display matches the labeled transducer head
Correct answer: Use a BNR (beam non-uniformity ratio) test tank or radiation force balance
A beam non-uniformity ratio test tank or radiation force balance is the standard method to objectively verify that an ultrasound transducer is producing the intended acoustic output.
Question 2: A TENS unit delivers no output despite fresh batteries and correct lead placement. What is the FIRST troubleshooting step?
- Replace the transducer head
- Inspect lead wires and electrode connectors for breaks or corrosion (Correct answer)
- Increase the intensity to maximum
- Soak electrodes in saline to improve conductivity
Correct answer: Inspect lead wires and electrode connectors for breaks or corrosion
Lead wire or connector failure is the most common cause of no output in a TENS unit, and inspecting these components should be the first troubleshooting step.
Question 3: Which statement BEST describes the purpose of the duty cycle control on an ultrasound device?
- It adjusts the frequency of the sound waves produced
- It controls the ratio of on-time to total cycle time, determining thermal vs. non-thermal effects (Correct answer)
- It sets the maximum safe treatment intensity in W/cm²
- It switches between continuous and surge modes of electrical stimulation
Correct answer: It controls the ratio of on-time to total cycle time, determining thermal vs. non-thermal effects
The duty cycle on an ultrasound unit determines the percentage of time sound energy is emitted, distinguishing between thermal (continuous) and non-thermal (pulsed) treatment effects.
Question 4: Before storing a fluidotherapy unit after clinical use, what maintenance step is MOST important?
- Drain and replace all cellulose particles immediately
- Clean the inlet filter and inspect the heating element thermostat (Correct answer)
- Lubricate the fan motor with mineral oil
- Submerge the unit in disinfectant for 30 minutes
Correct answer: Clean the inlet filter and inspect the heating element thermostat
Cleaning the inlet filter prevents particle clogging that reduces airflow and heating efficiency, and thermostat inspection ensures safe temperature regulation during future use.
Question 5: What does a 'wet-test' safety check on a hydrotherapy whirlpool verify?
- Water temperature accuracy against a calibrated thermometer
- The GFCI (ground fault circuit interrupter) trips correctly under electrical fault conditions (Correct answer)
- Turbine blade balance and rotational speed
- Chemical disinfectant concentration using test strips
Correct answer: The GFCI (ground fault circuit interrupter) trips correctly under electrical fault conditions
A wet-test checks that the GFCI trips correctly, ensuring electrical safety by interrupting power when a ground fault is detected in the water-immersion environment.
Question 6: An iontophoresis device displays an error code indicating electrode impedance is too high. The MOST likely cause is:
- Drug concentration in the reservoir is too low
- Electrode is dry or has poor skin contact due to insufficient moisture (Correct answer)
- The polarity switch is set incorrectly for the chosen drug
- The current amplitude exceeds the maximum rated output
Correct answer: Electrode is dry or has poor skin contact due to insufficient moisture
High impedance during iontophoresis most commonly results from a dry or poorly applied electrode that cannot establish adequate electrical contact with the skin.
Question 7: When inspecting a shortwave diathermy unit, which finding would require IMMEDIATE removal from service?
- The timer requires resetting after each treatment
- Frayed or cracked insulation on the applicator cables (Correct answer)
- The unit takes 3 minutes to reach operating temperature
- The intensity dial has slight resistance when turned
Correct answer: Frayed or cracked insulation on the applicator cables
Frayed or cracked cable insulation on shortwave diathermy creates a risk of electrical shock or burn injury and mandates immediate removal from service until repaired.
PAM Equipment Operation & Maintenance 2
When calibrating an ultrasound unit, what is the recommended method to verify that the transducer is producing acoustic output?