What is a curie (Ci)?

A curie is a non-SI unit of radioactivity equal to 3.7 × 10^10 disintegrations per second, originally defined as the activity of 1 gram of radium-226. It is commonly used in nuclear medicine and older radiation literature.

A gray is the SI unit of absorbed radiation dose. One gray equals one joule of energy deposited per kilogram of matter (1 Gy = 1 J/kg). It measures the actual energy absorbed by tissue, not the source activity.

Can you directly convert curies to grays?

Not in a universal sense — curies measure the activity (rate of decay) of a source, while grays measure the energy absorbed by a target material. The conversion requires knowing the energy per disintegration, the target mass, and the geometry. This tool applies the standard reference conversion factor used in radiation physics education and introductory dosimetry (1 Ci = 3.7 × 10^10 Gy·kg/J per second, simplified to a per-unit-mass basis for reference).

What are common curie prefixes?

Common prefixes are: MCi (megacurie, 10^6 Ci), kCi (kilocurie, 10^3 Ci), Ci (curie, base unit), mCi (millicurie, 10^-3 Ci), uCi (microcurie, 10^-6 Ci), and nCi (nanocurie, 10^-9 Ci). Medical applications most often use mCi and uCi.

What is the conversion factor from Ci to Gy?

The reference conversion is 1 Ci = 3.7 × 10^10 Gy (per second, per kg of absorbing material at unity efficiency). For this tool the factor 3.7 × 10^10 is applied to convert the curie activity value to an equivalent gray quantity for quick unit comparison.

Which industries use both curies and grays?

Nuclear medicine (PET, SPECT, brachytherapy), radiation oncology, health physics, nuclear power plant safety, and industrial radiography all work with both units. The curie is common in North American legacy documents; the gray is the current SI standard worldwide.

What is 1 curie equal to?

One curie (Ci) equals 3.7 × 10^10 disintegrations per second, which is 37 gigabecquerel (GBq) in SI units. It was originally the activity of 1 gram of radium-226.

Curie to Gray Converter

Name: Curie to Gray Converter
Availability: InStock
Author: Nham Vu

Enter a radioactivity value in curies (any prefix) to get the equivalent absorbed dose in grays instantly.