When they say dense breasts, do mammogram techs mean fat?

No-opposite. Typically it means there is not as much fat. As we age and have less estrogen the breasts get fatty replaced which makes them not as dense and easier to see abnormalities on the mammogram.
NO, the opposite. Dense breasts have less fatty tissue and more non-fatty tissue compared to breasts that aren't dense. Dense breasts have more gland tissue and especially more supportive tissue (also called stroma) that surrounds the gland.
No. Fat does the opposite. Fibroglandular tissue make breasts dense.
NO. Fatty breast are not dense. Fat is easy to see through on mammography and cancer detection is easier. Dense breast contain material, fibroglandular elements, that are hard to see through on mammography thus the mammogram is less reliable in dense breasts.
No. The opposite. Breasts are composed of fibroglandular stroma and fat. It is the fibroglandular part that shows up as white, or dense, on the mammogram.

Related Questions

I had a screening mammogram an it came back negative but report says heterogeneously dense breast, what does this mean and how accurate are the result?

Normal finding. Dense breasts on mammogram are usually seen in younger women with fuller breasts. I wonder why you would be getting a screening mammogram at age 35? Do you have a family history of breast cancer? Read more...
Dense breasts. "Dense" breasts are normal, but decrease the sensitivity of the mammo for detecting cancers. Some studies show that the sensitivity of mammography in this setting can decrease to as low as 50%. Also, dense breasts are an independent risk factor for developing breast cancer, and cancers discovered in women with dense breasts tend to be more advanced. Read more...