diff --git a/numbat/modules/core/dimensions.nbt b/numbat/modules/core/dimensions.nbt
index 9f639f34..b5ef7e38 100644
--- a/numbat/modules/core/dimensions.nbt
+++ b/numbat/modules/core/dimensions.nbt
@@ -75,6 +75,7 @@ dimension LuminousFlux = LuminousIntensity × Angle^2
 dimension Illuminance = LuminousFlux / Area
 dimension Luminance = LuminousIntensity / Area
 dimension Irradiance = Power / Area
+dimension Exposure = ElectricCharge / Mass
 
 dimension Activity = 1 / Time
 dimension AbsorbedDose = Energy / Mass
diff --git a/numbat/modules/units/cgs.nbt b/numbat/modules/units/cgs.nbt
index 187bd9fd..94cd6e7f 100644
--- a/numbat/modules/units/cgs.nbt
+++ b/numbat/modules/units/cgs.nbt
@@ -37,3 +37,13 @@ unit poise: DynamicViscosity = 1 dyn × s / cm^2
 @metric_prefixes
 @aliases(St: short)
 unit stokes: KinematicViscosity = cm^2 / s
+
+@name("rad")
+@url("https://en.wikipedia.org/wiki/Rad_(radiation_unit)")
+@metric_prefixes
+unit Rad: AbsorbedDose = cGy
+
+@name("Roentgen equivalent man")
+@url("https://en.wikipedia.org/wiki/Roentgen_equivalent_man")
+@metric_prefixes
+unit rem: EquivalentDose = cSv
diff --git a/numbat/modules/units/misc.nbt b/numbat/modules/units/misc.nbt
index cf64e29f..d0ef9aea 100644
--- a/numbat/modules/units/misc.nbt
+++ b/numbat/modules/units/misc.nbt
@@ -189,3 +189,21 @@ unit metric_tablespoon: Volume = 15 mL
 @url("https://en.wikipedia.org/wiki/Teaspoon")
 @aliases(metric_teaspoons, metric_tsp: short)
 unit metric_teaspoon: Volume = 1/3 × metric_tablespoon
+
+@name("Curie")
+@url("https://en.wikipedia.org/wiki/Curie_(unit)")
+@metric_prefixes
+@aliases(Ci: short)
+unit curie: Activity = 37 GBq
+
+@name("Rutherford")
+@url("https://en.wikipedia.org/wiki/Rutherford_(unit)")
+@metric_prefixes
+@aliases(Rd: short)
+unit rutherford: Activity = MBq
+
+@name("Röntgen")
+@url("https://en.wikipedia.org/wiki/Roentgen_(unit)")
+@metric_prefixes
+@aliases(roentgen)
+unit röntgen: Exposure = 2.58e-4 C/kg