US · guidance
CMS SOM App. D, Tag H0044
§486.108(b) Standard - Total Filtration
(1) The aluminum equivalent of the total filtration in the primary beam is not
less than shown in the following table except when contraindicated for a
particular diagnostic procedure.
Operating kVp Total filtration (inherent plus added)
Below 50 kVp…………………………… 0.5 millimeters aluminum.
50-70 kVp………………………………. 1.5 millimeters aluminum
Above 70 kVp…………………………… 2.5 millimeters aluminum
(2) If the filter in the machine is not accessible for examination or the total
filtration is unknown, it can be assumed that the requirements are met if
the half-value layer is not less than that shown in the following table:
Operating kVp Half-value layer
50 kVp……………… …………………… 0.6 millimeters aluminum
70 kVp…………………………………… 1.6 millimeters aluminum
90 kVp…………………………………… 2.6 millimeters aluminum
100 kVp………………………………….. 2.8 millimeters aluminum
110 kVp………………………………….. 3.0 millimeters aluminum
120 kVp………………………………….. 3.3 millimeters aluminum
________________________________________________________________________
History
Rev. 28; Issued: 09-07-07; Effective/Implementation Date: 09-07-07
Provenance
- Source
- cms.gov
- Retrieved
- 2026-07-22
- Edition
- som-2026-07-22
- Content hash
f1a3d6acce75a4919ddd8803b1a31633d333db1e5a3ee9a6a1138e9f8b65a649
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