Best imaging method for dx mets?

[KorynH]

I finished Herceptin in Dec. 09. End of July began having pain on right rib cage side. This has now been going on 6 weeks. This pain is oddly familiar to me from when my liver enzymes were 3x elevated during chemo Spring of 09. It is a dull achy pain. Comes and goes but is definitely every day. Rib x-rays and ct of abdomen show nothing. Liver function test normal. Onco is leaning towards a pet scan but also mentioned ultrasound or mri. Is there a gold standard for diagnosing this area (liver) after bc? My bc was missed for 2 years because it didn't show on imaging so I am understandably concerned that they just aren't ordering the correct imaging study. I am in the military system of medicine so insurance/money no problem. They are not restricted in what they can order. ANy advice greatly appreciated!