Radiation Dose

Radiation Dose

When radiation passes through tissue, it deposits energy. Quantifying this energy deposition is essential for radiation protection, medical imaging, and reactor safety.

Absorbed Dose

The absorbed dose $D$ is the energy deposited per unit mass:

$D = \frac{E}{m} \quad [\text{Gray, Gy} = \text{J/kg}]$

Equivalent Dose

Not all radiation types cause equal biological damage for the same absorbed dose. The equivalent dose $H$ accounts for this via the radiation weighting factor $w_R$:

$H = D \times w_R \quad [\text{Sievert, Sv}]$

Annual Dose Rate

For a radioactive source with activity $A$ (Bq = decays per second), depositing energy $E_d$ per decay into a mass $m$:

$\dot{H} = \frac{A \cdot E_d}{m} \times 3.156 \times 10^7 \text{ s/year} \times 10^3 \text{ mSv/Sv}$

Exposure Limits

• General public: 1 mSv/year
• Radiation workers: 20 mSv/year
• Single diagnostic CT scan: ~2–10 mSv

Your Task

All constants must be defined inside each function.

• absorbed_dose_Gy(energy_J, mass_kg) — absorbed dose in Gray
• equivalent_dose_Sv(absorbed_Gy, weighting_factor) — equivalent dose in Sievert
• annual_dose_rate_mSv(activity_Bq, dose_per_decay_J, mass_kg) — annual dose rate in mSv/year ($3.156 \times 10^7$ s/year)