Contrast Dose Calculator

Formula used

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How to use this calculator

1. Select a protocol (iodinated or gadolinium).
2. Enter patient weight and choose kg or lb.
3. Enter target dose and a compatible unit.
4. Enter contrast concentration from the vial label.
5. Optionally set flow rate to estimate injection duration.
6. Optionally apply a max volume cap or fixed volume override.
7. Press Calculate to view results and export options.

Example data table

Professional guide

1) Purpose of contrast dose estimation

Contrast administration can be described as an amount delivered to the patient and the volume needed to deliver that amount. This calculator links those pieces using mass, target dose, and concentration so the final volume is unit-consistent. It supports iodinated iodine-load style dosing and gadolinium molar dosing.

2) Inputs that drive volume calculations

The strongest drivers are patient mass and the chosen target dose. Concentration then converts an amount into a practical volume. For example, a fixed delivered amount of 42 gI requires 120 mL at 350 mgI/mL, but only about 114 mL at 370 mgI/mL. Accurate label values matter.

3) Iodinated protocols and iodine load

Weight-based iodine delivery is commonly expressed in mgI/kg. A 70 kg patient at 600 mgI/kg corresponds to 42,000 mgI (42 gI). With 350 mgI/mL, that maps to 120.0 mL. The calculator also reports delivered mgI/kg after caps or overrides.

4) Gadolinium protocols and molar dosing

MRI contrast agents are often represented by molar concentration. A 0.10 mmol/kg target for 60 kg corresponds to 6.0 mmol total. At 0.5 mmol/mL, that equals 12.0 mL. If you enter mmol/L, the tool converts internally to mmol/mL before computing volume.

5) Flow rate and injection timing metrics

Flow rate turns volume into time. For 120 mL at 4 mL/s, the injection duration is 30 s. Delivery rate is concentration times flow. At 350 mgI/mL and 4 mL/s, iodine delivery is 1400 mgI/s, or 1.400 gI/s. These metrics help compare protocols objectively.

6) Using caps and overrides responsibly

A max-volume cap limits the computed volume and automatically recalculates the delivered dose from the capped volume. The fixed-volume override does the reverse: it derives delivered dose from the entered volume. Both options are useful for audits, simulations, and standardization checks across scanners.

7) Interpreting exported results

CSV and PDF exports capture the protocol name, generation time, and a structured list of outputs. This format supports peer review and traceability: you can paste CSV into spreadsheets or attach the PDF to study notes. Compare “recommended volume,” “delivered dose,” and “duration” between cases.

8) Quality control and documentation tips

Record the concentration from the vial, the measured patient mass, and the flow setting used on the injector. If a cap was applied, document both the cap and the resulting delivered dose. Consistent documentation reduces variability, improves reproducibility, and makes protocol updates easier to evaluate.

FAQs

1) What does “mgI/kg” represent?

It is iodine mass delivered per kilogram of patient mass. The calculator multiplies mgI/kg by mass to get total mgI, then divides by concentration to return a volume.

2) Why does concentration change the volume so much?

Concentration is the conversion factor from amount to volume. Higher concentration means fewer milliliters are needed for the same delivered iodine or mmol target.

3) Can I compute delivered dose from a fixed volume?

Yes. Enable the fixed-volume override, enter the volume, and the tool derives the delivered dose from volume, concentration, and patient mass. This is useful for audits.

4) What does the max volume cap do?

If the computed volume exceeds the cap, the tool limits volume to the cap and recalculates the delivered dose and total amount from that capped volume.

5) How is injection duration calculated?

Duration equals volume divided by flow rate. If you provide flow in mL/min, the calculator converts it internally to mL/s before computing time.

6) Why is there an optional eGFR adjustment?

It applies a small conservative scaling factor for simulation and comparison scenarios when renal function is considered. It is not a clinical recommendation and should not replace local policies.

7) Are the example rows meant to be clinical defaults?

No. They illustrate unit handling and arithmetic only. Always follow your institution’s protocols and labeling, and use this tool for education, research checks, and consistent documentation.