Radiation Protection in Mammography: Recommended Safety Procedures for the Use of Mammographic X-Ray Equipment - Safety Code 33

Appendix III

Shielding Guides for Storage of Mammographic Film

The following table provides the thicknesses of lead required to reduce the radiation level to the film and loaded cassettes to 1.75 µGy (0.2 mR) for a weekly workload of 1000 mA-min at 35 kilovolts (peak).

Table 10: Shielding Guides for Storage of Mammographic Film -Storage time for secondary barriers

	Distance from X-ray tube to stored films
	1 m	2m	3m	4m	5m
1 day	0.4 mm	0.3 mm	0.2 mm	0.2 mm	0.1 mm
1 week	0.5 mm	0.4 mm	0.4 mm	0.3 mm	0.3 mm
1 month	0.6 mm	0.5 mm	0.4 mm	0.4 mm	0.4 mm
1 year	0.7 mm	0.6 mm	0.6 mm	0.6 mm	0.5 mm