How to Use the BED Calculator
To effectively use the BED calculator, input the following measurements:
- Irradiation duration: Specify whether the irradiation lasts less than a few minutes or longer.
- Dose per fraction (Gy): Enter the dose administered during a single session of irradiation.
- Total dose (Gy): Input the cumulative dose, calculated as the number of fractions multiplied by the dose per fraction.
- Dose rate factor (g): Accounts for the repairability of cells during prolonged exposure.
The calculator will provide results for:
- BED (Biologically Effective Dose): Indicates the effectiveness of the given dose in achieving therapeutic goals.
- EQD2 (Equivalent Dose in 2 Gy Fractions): Standardizes treatment doses to allow comparison across different schedules.
What’s a Healthy or Unhealthy Range?
- Healthy Range: Depends on the tissue being treated and the treatment objectives. Typically, treatment planning ensures the BED is high enough to achieve tumor control while minimizing damage to healthy tissues.
- Unhealthy Range: Overexposure can cause severe damage to sensitive tissues (e.g., central nervous system) or lead to long-term complications.
Why Use This Calculator?
- Precision in Planning: Accurately compare various treatment schedules.
- Standardization: Helps ensure compliance with clinical protocols.
- Informed Decisions: Provides clinicians with insights to adjust treatment for optimal patient outcomes.
Use of BED in Radiotherapy
The BED formula was developed to quantify treatment expectations and aid in clinical decisions. By calculating the biologically effective dose, clinicians can:
- Compare different treatment types.
- Evaluate research findings with precision.
- Combine results from multiple BED calculations for a comprehensive treatment plan.
Use of BED in Radiotherapy
The standard formula for calculating BED is:
BED = Total dose × (1 + (Fraction dose / αβ))
For longer irradiation durations:
BED = Total dose × (1 + [(g × Fraction dose )/ αβ ]),
where:
g = Dose rate factor of intracellular repair; and
αβ = α/β ratio.
EQD2 Formula
We've also decided to add the EQD₂ function to the BED calculator – to save you time! If you still want to compute it by yourself, here's the equation you'll need:
EQD₂ = Total dose × ((Fraction dose + αβ) / (2 + αβ)),
where:
αβ = α/β ratio.
EQD₂ is the equivalent of a total dose served in 2 Gy fractions.
Reminder
The biologically effective dose (BED) should not be confused with the biological equivalent dose used in radiation therapy.
Let me know if you’d like any further refinements or additional details!