Living the Dream?

I'm new, Hello everyone! I hope to receive a great number of responses as I hope to change my career and ultimately my life to a long standing dream.

Maybe I'm being foolish however, throw caution to the wind and I'll throw it out there anyway. Since I can remember people and helping others has always been a priority. I am beyond patient with others (not myself), and truly enjoy helping others. I've always felt the feeling you get from helping others is one of the purest feelings you can feel... 

When I first went to college I started in the radiology field as I worked in a radiology office with physicians who only studied X-rays. Upon entering the clinicals phase I quickly realized I truly wanted to be a Doctor of radiology... it was the oddest thing. In fact I'd never felt more sure of anything in my life and it still remains with me today almost 20 years later. I've never stopped thinking of it...

At that time I had started a young family and my husband while supportive of school could not fathom the idea of several more years. I found myself lost and confused rather quickly. I dropped out of the clinicals and while that was foolish I found another program at a different school which ultimately lead me into marketing management. The career has been fulfilling from an artistic and problem solving stand point however, that feeling of standing there with the head radiologist explaining the small details to his medical radiology students while I was supposed to be following another class was amazing. Not only amazing but life long lasting... I've tried on many shoes for a moment. But I must say those were the shoes that fit most beautifully. I've been successful and I've shared my moments of ups and downs however, nothing has given  me the feeling I had that day!

I continued to work temporarily in a radiologists office and learned everything they were willing to share. Realizing this was becoming a choice of my family and husband or this dream that didn't seem to provide a means of realization, I turned to something entirely different. However, the dream still nags at me like a glimmer of hope to realize more then the dream but life a life long prophecy.

So, now I'm forty years old and I want to do it... my questions are how? How do I make the world still go round and go back to school? How do people generally pay for a living and go back to school.

Any suggestions?

Here's where I am at; (as I hope a lot of people do respond with positive suggestions)

I'm in the midst of leaving my corporate position... in which I am trading for some independent work. I have a couple companies I've started up that over time require less and less of my time.  Which in a perfect world would pay for everything... However, how do other people do it? How are you doing it?

Thank you in advance for your response. Michelle