Marion,
"10 Myths About Mammograms" is an excellent headline/title and will help you sell your story.
The advice you've been given above is good. However, when you're writing an article, multiple submissions are frowned upon. Newspapers like to feel special. But a press relsease is another matter; publications understand that press releases go to many media.
NOW: Can you think of a peg for for your story, something timely you can hang it on: a walkathon to raise money to fight breast cancer? A health fair? Newspapers love stories with pegs. I realize your subject is timeless, but that's how newspapers think. Don't forget to sell your expertise; I gather you're a nursing student.
You are a good writer. Your questions are succinct.
I have been a writer and editor at daily newspapers for more than 30 years.
Good luck!