diff --git a/yt/data_objects/tests/test_data_containers.py b/yt/data_objects/tests/test_data_containers.py
index d0f99c6a799..f958de06628 100644
--- a/yt/data_objects/tests/test_data_containers.py
+++ b/yt/data_objects/tests/test_data_containers.py
@@ -126,8 +126,8 @@ def test_to_frb(self):
             data_source=dd,
         )
         frb = proj.to_frb((1.0, "unitary"), 64)
-        assert_equal(frb.radius, (1.0, "unitary"))
-        assert_equal(frb.buff_size, 64)
+        assert_equal(frb.radius, ds.quan(1.0, "unitary"))
+        assert_equal(frb.buff_size, (64, 64))
 
     def test_extract_isocontours(self):
         # Test isocontour properties for AMRGridData
diff --git a/yt/visualization/fixed_resolution.py b/yt/visualization/fixed_resolution.py
index 7e1123cdf6f..8e1316f19fc 100644
--- a/yt/visualization/fixed_resolution.py
+++ b/yt/visualization/fixed_resolution.py
@@ -1,9 +1,11 @@
 import sys
 import weakref
 from functools import partial
+from numbers import Number
 from typing import TYPE_CHECKING, Optional
 
 import numpy as np
+from unyt import unyt_quantity
 
 from yt._maintenance.deprecation import issue_deprecation_warning
 from yt._typing import FieldKey, MaskT
@@ -584,16 +586,42 @@ class CylindricalFixedResolutionBuffer(FixedResolutionBuffer):
     def __init__(self, data_source, radius, buff_size, antialias=True, *, filters=None):
         self.data_source = data_source
         self.ds = data_source.ds
-        self.radius = radius
-        self.buff_size = buff_size
+        self._set_radius(radius)
+        if np.isscalar(buff_size):
+            self.buff_size = (buff_size, buff_size)
+        else:
+            self.buff_size = buff_size
+        self.bounds = self._get_bounds()
         self.antialias = antialias
-        self.data = {}
+        self.data: dict[str, ImageArray] = {}
+        self.mask: dict[str, MaskT] = {}
         self._filters = filters if filters is not None else []
 
         ds = getattr(data_source, "ds", None)
         if ds is not None:
             ds.plots.append(weakref.proxy(self))
 
+    def _set_radius(self, r) -> None:
+        if self.ds is None:
+            # not attempting to solve this case right now
+            raise RuntimeError("boom 1")  # tmp
+        else:
+            if (
+                isinstance(r, tuple)
+                and len(r) == 2
+                and (isinstance(r[0], Number) and isinstance(r[1], str))
+            ):
+                r = self.ds.quan(*r).to("code_length")
+            elif isinstance(r, unyt_quantity):
+                r = self.ds.quan(r).to("code_length")
+            else:
+                raise RuntimeError("boom 2")  # tmp
+        self.radius = r
+
+    def _get_bounds(self) -> tuple[float, float, float, float]:
+        dx = dy = self.radius.item()
+        return (0.0, dx, 0.0, dy)
+
     @override
     def _generate_image_and_mask(self, item) -> None:
         buff = np.zeros(self.buff_size, dtype="f8")
@@ -604,7 +632,7 @@ def _generate_image_and_mask(self, item) -> None:
             self.data_source["theta"],
             self.data_source["dtheta"],
             self.data_source[item].astype("float64"),
-            self.radius,
+            extents=self.bounds,
             return_mask=True,
         )
         self.data[item] = ImageArray(