The physics beneath the practice
General physics & the human body
Before radiation physics comes physics itself. This section covers the basic laws of motion, energy, fluids, heat, waves, electricity and light, then shows how each one runs inside the body you treat.
How to use this section
Read the fundamentals once for the concepts, then work the body section until each number feels familiar. Finish with the cards, quiz and calculations — the same physics reappears in dosimetry, imaging and patient handling.
Basic general physics
Eleven topics that carry every calculation in radiation therapy. Open a card for the working detail and the human-body connection.
The SI units you will actually use
Derived units are built from the seven SI base units. Recognizing them is half of reading a formula correctly.
| Quantity | Unit | Symbol |
|---|---|---|
| Length | meter | m |
| Mass | kilogram | kg |
| Time | second | s |
| Force | newton | N = kg·m/s² |
| Energy | joule | J = N·m |
| Power | watt | W = J/s |
| Pressure | pascal | Pa = N/m² |
| Frequency | hertz | Hz = 1/s |
| Voltage | volt | V = J/C |
| Current | ampere | A = C/s |
| Absorbed dose | gray | Gy = J/kg |