diff --git a/.github/workflows/SpellCheck.yml b/.github/workflows/SpellCheck.yml
new file mode 100644
index 0000000..c344f6d
--- /dev/null
+++ b/.github/workflows/SpellCheck.yml
@@ -0,0 +1,13 @@
+name: Spell Check
+
+on: [pull_request]
+
+jobs:
+  typos-check:
+    name: Spell Check with Typos
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout Actions Repository
+        uses: actions/checkout@v4
+      - name: Check spelling
+        uses: crate-ci/typos@master
diff --git a/Project.toml b/Project.toml
index 78a7b50..8aafee7 100644
--- a/Project.toml
+++ b/Project.toml
@@ -14,6 +14,6 @@ Requires = "ae029012-a4dd-5104-9daa-d747884805df"
 FFTW = "1.4.5, 1.5"
 ImageGeoms = "0.9, 0.10"
 Interpolations = "0.14, 0.15"
-LazyGrids = "0.4, 0.5"
+LazyGrids = "0.4, 0.5, 1"
 Requires = "1.3"
 julia = "1.10"
diff --git a/_typos.toml b/_typos.toml
new file mode 100644
index 0000000..75d25c4
--- /dev/null
+++ b/_typos.toml
@@ -0,0 +1,4 @@
+[default]
+extend-ignore-identifiers-re = [
+    "iy",
+]
diff --git a/docs/make.jl b/docs/make.jl
index 905b408..ca3cf25 100644
--- a/docs/make.jl
+++ b/docs/make.jl
@@ -2,8 +2,8 @@ execute = isempty(ARGS) || ARGS[1] == "run"
 
 org, reps = :JuliaImageRecon, :Sinograms
 eval(:(using $reps))
-using Documenter
-using Literate
+import Documenter
+import Literate
 
 # https://juliadocs.github.io/Documenter.jl/stable/man/syntax/#@example-block
 ENV["GKSwstype"] = "100"
@@ -23,7 +23,7 @@ binder_root_url =
 
 
 repo = eval(:($reps))
-DocMeta.setdocmeta!(repo, :DocTestSetup, :(using $reps; import $reps); recursive=true)
+Documenter.DocMeta.setdocmeta!(repo, :DocTestSetup, :(using $reps); recursive=true)
 
 # preprocessing
 inc1 = "include(\"../../../inc/reproduce.jl\")"
@@ -77,7 +77,7 @@ format = Documenter.HTML(;
     assets = ["assets/custom.css"],
 )
 
-makedocs(;
+Documenter.makedocs(;
     modules = [repo],
     authors = "Jeff Fessler and contributors",
     sitename = "$repo.jl",
@@ -90,7 +90,7 @@ makedocs(;
 )
 
 if isci
-    deploydocs(;
+    Documenter.deploydocs(;
         repo = "github.com/$base",
         devbranch = "main",
         devurl = "dev",
diff --git a/src/geom/common.jl b/src/geom/common.jl
index fc60bfe..b279b71 100644
--- a/src/geom/common.jl
+++ b/src/geom/common.jl
@@ -27,17 +27,29 @@ typically degrees.
 angles(rg::RayGeom) =
     range(rg.orbit_start, length = rg.na, step = rg.orbit / rg.na)
 
-# angles in radians
+"""
+    _ar(rg::RayGeom)
+Angles in radians.
+"""
 _ar(rg::RayGeom) = to_radians(angles(rg))
 
-# minimum orbit for a fan-beam short scan
+"""
+    _orbit_short(rg::RayGeom)
+Minimum orbit for a fan-beam short scan.
+"""
 _orbit_short(rg::RayGeom) = 180 + 2 * rad2deg(_gamma_max(rg)) # (degrees)
 
-# distance from detector arc focal spot to source for fan-beam
+"""
+   _dfs(::Union{SinoFan,CtFan})
+Distance from detector arc focal spot to source for fan-beam.
+"""
 _dfs(::Union{SinoFanArc{Td},CtFanArc{Td}}) where Td = zero(Td)
 _dfs(::Union{SinoFanFlat{Td},CtFanFlat{Td}}) where Td = Inf * oneunit(Td)
 
-# distance from source to origin for fan-beam
+"""
+    _dso(rg::Union{SinoFan,CtFan}) = rg.dsd - rg.dod
+Distance from source to origin for fan-beam.
+"""
 _dso(rg::Union{SinoFan,CtFan}) = rg.dsd - rg.dod
 
 """