Ontario health guidelines recommend that women aged 50 and over get screened using a mammogram once every two years. The guidelines recommend that women aged 30 and over get screened using a mammogram once every year if they are in a high risk group including a family history of breast cancer. Mammograms use which physical property to generate an image? Beta(+)-emitting radioisotopes MRI Ultrasound Gamma-emitting radioisotopes X-rays