Guinea Pig passing blood

Question
Thank you for responding to my question so quickly. We had previously asked the vet for an X ray, which he declined. He said that it would not show anything. Could she have swallowed her tooth? The vet noticed that one was broken. She still feels uneasy when she passes urine and she is not eating as much, but she no longer seems to be passing blood. I have seen 3 vets and they seem eager to put her to sleep. However, as she still seems lively and happy, I am reluctant to do this. Could I demand an X-Ray, and would any anesthetic be needed?
Thank you for you time.
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The text above is a follow-up to ...

-----Question-----
My Guinea Pig is 4 years old. And has been passing blood when she goes to the bathroom. I have taken her to the vet, and they gave her an injection, but she isn't any better. She isn't eating much, only soft food that I give her. She is also crying as she passes the blood. Do you have any other suggestions?
Thanks
-----Answer-----
Did the vet do an X-ray of her kidneys and bladder? It could possibly be a kidney or bladder stone, in which an injection of antibiotics would not help. If she does have a kidney or bladder stone the vet will need to either do surgery, or you could try to make her urine more acidic, by adding a lot of apple, beetroot, and vitamin C. Antibiotics also need to be given orally every day to cure cystitis, if that is what is causing the bleeding, cystitis is a kidney and/or bladder infection. The best antibiotic to give are sulfur based ones also. Let me know if you have any more questions.
Brittany

Answer
Stones can be seen on X-rays, the best method would be an ultrasound to see if there are any stones, but x-rays are easier and less expensive, the stones can be sen as round small masses with a white cloudy shadow around their edges, although when first developing the stones can be harder to see. I definatly would not put her to sleep unless you think she is suffering. No anesthetic is needed for an X-ray, and you could demand one, just make sure you go to an exotic animal vet who knows what he/she is looking at in an X-ray of a guinea pig. If she would have swallowed her tooth it wouldn't have done much, and it would have passed through her intestines.
Brittany