1.avidity; kekuatan asam basa, 2. dalam imunologi, suatu pengukuran yang tidak tepat dari kekuatan antigen -antibodi yang berdasarkan kepada kecepatan dimana kekomplekan terbentuk (kamus istilah kedokteran, dr. Difa Dania).

Untuk menerjemah secara tepat sebagai apa, mungkin lebih baik disertakan contoh kalimat yang jelas

--------------------------------------------------
Note added at 3 hrs (2009-08-10 05:08:20 GMT)
--------------------------------------------------

Atau bisa dterjemahkan, ukuran kekuatan antigen-antibodi

We decided to investigate the use of a radioguided intraoperative technique to select the specific lymph nodes that should be studied intensely. It is known that intravenously injected 18F-fluorodeoxyglucose (FDG) accumulates in thoracic lymph nodes when they harbor metastatic carcinoma cells, and this underlies the utility of positron emission tomography (PET) imaging in clinical staging of lung cancer patients [8]. We hypothesized that local detection of gamma radiation using an intraoperative handheld gamma probe after intravenous FDG injection would identify lymph nodes containing metastases in a much more sensitive manner. Detailed pathologic analysis (multiple step sections and immunohistochemistry) of these lymph nodes would then result in more accurate staging than that provided by conventional (H&E) staining.

Dari Radioguided Detection of Lymph Node Metastasis in Non-Small Cell Lung Cancer
Chumy Nwogu, MDa

Menurut saya FDG disini sebagai penunjuk apakah terdapat penyebaran (metastase) tumor dan juga dapat dipakai untuk menentukan tingkat keganasan tumor.