Iontophoresis is best described as which type of modality?

• A. Ultrasound
• B. Light therapy
• C. Deep thermal/electrical
• D. Mechanical vibration

Answer: (C)

Iontophoresis uses electrical current to move charged medication molecules through the skin into underlying tissues. That makes it an electrical modality, since the primary energy form involved is electrical, not ultrasound, light, or mechanical vibration. While the current can cause some surface heating, the key feature is the delivery of ions via electromigration under direct current, enabling localized drug penetration deeper than surface application. This is why it’s described as a deep electrical modality rather than one of the other energy forms.