Using simple phantoms for teaching diagnostic and radiation therapy principles in hands-on medical physics outreach.

Hands-on, accessible learning experiences offer an effective way to introduce students to medical physics. This case report describes the development, implementation, and instructional design of two straightforward educational activities included in a single lesson plan. The activities model diagnostic nuclear medicine imaging and external beam radiation therapy using materials built from simple, fabricated, and commercially available sources. The diagnostic activity uses sealed radioactive check sources and handheld survey meters to simulate the process of localizing a "tumor" within a phantom, allowing students to explore principles of radiation detection, measurement variability, and diagnostic uncertainty. The treatment activity employs a gelatin-based phantom with an embedded target and wooden skewers to represent radiation beams, providing an approachable way to examine the role of precision, geometry, and planning in radiation therapy. The activities were originally developed for secondary students and later expanded for use with diverse audiences, including middle school, high school, and undergraduate learners; educators; and community members. In 2025, both activities were presented at national professional meetings for medical physicists and physics educators, where associated materials were shared widely to support broader adoption. The lesson structure combines concise instructional presentations with guided hands-on exploration, enabling educators to tailor depth, language, and pacing to the needs of different groups. By connecting simplified physical models to medical experiences familiar to many students, these activities provide an approachable entry point into medical physics concepts and careers.