Go to this website:
    http://www.medical-training.info/featured-schools.html

This will give you some idea about the field you want to get in to.

While a radiology technician's job is somewhat technical, to be good at
it you have to be willing to work with a lot of sick and injured and
frightened people.  You may have to be extremely patient in order to
get them positioned correctly for the images at a time when they are in
pain, sedated, terrified, confused or extremely anxious.  You will have
to handle their bodies in ways they may find disturbing, at times when
they are least able to handle the emotional stress.  They may not be
able to understand or comply with your instructions due to hearing
problems, language problems, mental problems or distraction by pain,
sedation, anxiety or stress. Through all this, you must appear
professional. competent, empathetic and encouraging, all day long,
patient after patient, even when you have worries of your own.

If this doesn't appeal to you, you should try to find a technical area
in medicine that involves less patient contact, or less contact with
patients in distress.  Medicine uses a lot of electronic equipment
these days, and it is maintained, and sometimes constructed, by
electronics technicians.  Some technical occupations, like audiology,
work with less stressed patients so are less emotionally demanding on
the technician.  There are new technical occupations in medicine all
the time.  As well, hospitals often need good tech support people for
their conventional computers.  They have trouble getting and holding
them because they generally don't pay as well as other fields.

One way to find out if you are suited to a particular occupation is to
talk to several people who are already doing it, are good at it, and
enjoy their work.  Find out what they like and dislike about it.  Note
that until recently, at least, computer jocks have been extremely
overpaid for what they do, compared to medical workers who have better
competence and far more responsibility.  After all, if a computer jock
screws up, usually the worst that can happen is that people lose money
or get pissed off.  A mistake by a medical worker can have disastrous
consequences.  So note that you'll likely get paid a good deal less for
a job that has a great deal less slack.  You'll have to look clean and
well-groomed and be very punctual as well.

As for being too old, I'd say no.  A friend of mine, after 20 years as
a carpenter, decided that what he really liked was working with old
people and trained as a geriatric nurse.  He enjoys the work very much,
and found that elderly men in his rural area are often more comfortable
being cared for by a man than a woman.

At any rate, get a good idea of what the job is like before you invest
the time and effort.  Best of luck to you!

Indeed. Radiology technicians are in high demand.