title: Fluorine-18-fluorodeoxyglucose-guided breast cancer surgery with a positron-sensitive probe: validation in preclinical studies.
abstract: In this study, the feasibility of utilizing 2-deoxy-2-fluoro-d-glucose (FDG) in conjunction with a positron-sensitive intraoperative probe to guide breast tumor excision was investigated.
  
  
  METHODS
  The probe was constructed with a plastic scintillator tip coupled to a photomultiplier tube with fiber optic cable. Anticipated resolution degradation was evaluated by measurement of line spread functions in the presence of background radiation. Realistic photon background distributions were simulated with a human torso phantom and a cardiac insert. The relationship between resolution and energy threshold was measured to find the optimal discriminator settings. In addition, probe sensitivity as a function of energy threshold was determined for various size-simulated tumors. Finally, the ability to localize breast cancers in vivo was tested in a rodent model. Mammary rat tumors implanted in Lewis rats were examined after injection with FDG; these results were correlated with those of histologic analyses.
  
  
  RESULTS
  Measurements of line spread functions indicated that resolution could be maximized in a realistic background photon environment by increasing the energy threshold to levels at or above the Compton continuum edge (340 keV). At this setting, the probe's sensitivity was determined to be 58 and 11 cps/muCi for 3.18- and 6.35-mm diameter simulated tumors, respectively. Probe readings correlated well with histologic results: the probe was generally able to discriminate between tumor and normal tissue.
  
  
  CONCLUSIONS
  This study indicates that breast cancer surgery guided by a positron-sensitive probe warrants future evaluation in breast-conserving surgery of patients with breast cancer.
authors.affiliation: Department of Radiation Oncology, University of Michigan Medical Center, Ann Arbor 48109-0552, USA.
authors.forename: R R
authors.initials: RR
authors.lastname: Raylman
authors.forename: S J
authors.initials: SJ
authors.lastname: Fisher
authors.forename: R S
authors.initials: RS
authors.lastname: Brown
authors.forename: S P
authors.initials: SP
authors.lastname: Ethier
authors.forename: R L
authors.initials: RL
authors.lastname: Wahl
mesh_terms: D000818:Animals; D001610:Beta Particles; D001943:Breast Neoplasms / Q000000981:diagnostic imaging / Q000601:surgery; D003847:Deoxyglucose / Q000031:analogs & derivatives*; D004867:Equipment Design; D005240:Feasibility Studies; D005260:Female; D005462:Fluorine Radioisotopes; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007430:Intraoperative Care; D008325:Mammary Neoplasms, Experimental / Q000000981:diagnostic imaging* / Q000601:surgery*; D019047:Phantoms, Imaging; D016719:Radioimmunodetection / Q000295:instrumentation*; D051381:Rats; D011917:Rats, Inbred Lew
chemical_list: D005462:Fluorine Radioisotopes; D019788:Fluorodeoxyglucose F18; D003847:Deoxyglucose