B E D
Low α/β ratio for prostate adenocarcinoma
Why This Health Metric Matters
Why: This calculation helps assess important health parameters for clinical and personal wellness tracking.
How: Enter your values above and the calculator will apply validated formulas to compute your results.
- ●Evidence-based calculations
- ●Used in clinical settings worldwide
- ●Regular monitoring recommended
Sample Clinical Scenarios
☢️ Prostate SBRT
Stereotactic body radiation therapy for prostate cancer: 7.25 Gy × 5 fractions
Click to load this scenario
🫁 Lung Cancer Conventional
Standard fractionation for NSCLC: 2 Gy × 30 fractions over 6 weeks
Click to load this scenario
🎀 Breast Hypofractionation
Modern hypofractionated breast cancer treatment: 2.67 Gy × 15 fractions
Click to load this scenario
🗣️ Head & Neck Standard
Definitive radiation for head & neck SCC: 2 Gy × 35 fractions
Click to load this scenario
🦴 Palliative Spine Metastases
Single fraction palliative treatment for spine mets: 8 Gy × 1 fraction
Click to load this scenario
Enter Treatment Parameters
Dose Parameters
Tissue Parameters
⚠️For informational purposes only — not medical advice. Consult a healthcare professional before acting on results.
🏥 Health Facts
— WHO
— CDC
What is Biologically Effective Dose (BED)?
Biologically Effective Dose (BED) is a measure used in radiation oncology to quantify the true biological effect of a radiation treatment. It accounts for both the total dose delivered and the dose per fraction, recognizing that the same total dose can have different biological effects depending on how it's fractionated.
Linear-Quadratic Model
BED is derived from the linear-quadratic model of cell survival, which describes how radiation kills cells through both single-hit (α) and double-hit (β) mechanisms.
Key Principle:
Cell survival depends on both direct DNA damage (α) and accumulated sublethal damage (β)
Alpha/Beta Ratio
The α/β ratio represents the dose at which linear (α) and quadratic (β) cell kill components are equal. It varies by tissue type and is crucial for treatment planning.
Typical Values:
- Tumors: 8-10 Gy (fast-growing)
- Prostate: 1.5-3 Gy (slow-growing)
- Late effects: 2-4 Gy
EQD2 Conversion
EQD2 converts any fractionation scheme to the equivalent dose if given in standard 2 Gy fractions, enabling comparison of different treatment regimens.
Clinical Use:
Compare hypofractionated and conventional treatments on equal terms
How Does the BED Calculator Work?
The BED calculator applies the linear-quadratic radiobiological model to calculate the true biological effect of a radiation treatment. By entering dose parameters and selecting appropriate tissue type, clinicians can compare different fractionation schemes and optimize treatment planning.
☢️ Calculation Process
Step-by-Step
- 1Enter total dose or dose per fraction with number of fractions
- 2Select tissue type to auto-populate α/β ratio
- 3Calculator computes BED using the LQ model formula
- 4EQD2 is derived for standardized comparison
Why BED Matters
- Enables comparison of different fractionation schemes
- Predicts late normal tissue effects
- Guides hypofractionation decisions
- Essential for SBRT/SRS planning
When to Use the BED Calculator
The BED calculator is essential in radiation oncology for treatment planning, comparing fractionation schemes, and ensuring safe and effective radiation delivery across various clinical scenarios.
Treatment Planning
Compare different fractionation schedules to optimize tumor control while minimizing normal tissue toxicity.
Applications:
- SBRT/SRS planning
- Hypofractionation evaluation
- Re-irradiation assessment
Dose Comparison
Convert different regimens to EQD2 for standardized comparison when reviewing literature or changing protocols.
Use Cases:
- Protocol comparison
- Literature review
- Clinical trial design
Safety Assessment
Evaluate late effect risks for organs at risk and ensure normal tissue tolerances are respected.
Safety Checks:
- Late toxicity prediction
- OAR tolerance verification
- Cumulative dose tracking
BED and EQD2 Calculation Formulas
These formulas are derived from the linear-quadratic model of cell survival and are fundamental to modern radiation oncology treatment planning.
Core Formulas
Biologically Effective Dose (BED)
Where D = total dose (Gy), d = dose per fraction (Gy), α/β = tissue-specific ratio (Gy)
Equivalent Dose in 2 Gy Fractions (EQD2)
Alternatively: EQD2 = D × [(d + α/β) / (2 + α/β)]
Relationship Between Parameters
Calculator will auto-calculate if two of three values are provided