⚛️ Advanced Medical Physics Simulation

Collision vs Radiative Kerma | Inverse Square Law | Electronic Equilibrium
100 keV
Radiative losses (g) become significant >10 MV
Density affects electron range and bremsstrahlung
Diverging beam loses CPE due to geometric divergence
Shows collision vs radiative kerma split
2x
Note: At 100 keV, radiative loss fraction (g) ≈ 0.1%. Values shown are exaggerated for visibility. Clinically relevant for >10 MV beams.

🔬 Interaction Visualization

Build-up Region
X-ray Photons
Electrons (Secondary)
Energy Deposition
0
Active Photons
0
Active Electrons
0%
Radiative Loss (g)
Current Region: Build-up Region
Electron fluence is building up. Absorbed Dose < Kerma.

📊 Depth Dose Profile

Collision Kerma (Kcol)
Energy transferred to electrons that results in ionization/collision losses. Directly related to absorbed dose under CPE.
Absorbed Dose (D)
Energy actually deposited locally. Under CPE: D = Kcol. Always D ≤ Kcol + Krad.

📚 Fundamental Concepts

Total Kerma (K)

Sum of initial kinetic energies of all charged particles liberated by uncharged particles per unit mass.

K = Kcol + Krad

Collision Kerma (Kcol)

Portion of kerma that results in collision interactions (ionization/excitation). Available for local absorption.

Kcol = K(1 - g)

Radiative Kerma (Krad)

Energy lost to radiative processes (bremsstrahlung). g-factor increases with energy and Z² of medium.

g ≈ EZ/800 (approximate)

Inverse Square Law

In diverging beams, photon fluence ∝ 1/r². Causes loss of CPE even without attenuation. Critical for clinical dosimetry.

Φ ∝ 1/d²