Every third Friday in October is recognized as National mammography Day during Breast cancer Awareness Month (October).

According to nationaldaycalendar.com:

National Mammography Day serves as a day reminding all women that the best defense is early detection. A mammogram can often detect a problem before there is any outward physical sign. Make sure you get your regular checkups.

Self-Examination is an alternative to getting a Mammogram but not necessarily as effective.  Despite mammograms being a more relizble source for  Breast cancer detection