title: Scintimammography and single-photon emission computed tomography for postoperative image guidance for radiation treatment planning in breast cancer patients.
abstract: OBJECTIVE
  To evaluate post-surgical tumor-metabolic regions outside of the computed tomography (CT)-defined volume for radiation therapy (RT) planning using functional imaging of scintimammography (SMG) ± single photon emission computerized tomography (SPECT) in breast cancer (BC) patients.
  
  
  METHODS
  62 operated high-risk BC females, mean age 50.45 years, underwent SMG±SPECT before RT planning. Twenty-one and twelve patients with stage I and IIa respectively had lumpectomy (LT) with axillary lymph node dissection (ALND), and modified radical mastectomy (Patay) + ALND was realized in 29 stage IIb-III patients. All SMG images, positive for viable tumor tissue (VTT) or metastatically involved lymph nodes (LNs) were verified cytologically/ histologically. Three early planar and delayed images were acquired after i.v. administration of 550-740 MBq 99mTc- MIBI or 99mTc-TF. Uptake values (UV) > 1.65 revealed VTT.
  
  
  RESULTS
  Data in 49 (79%) of 62 patients were characterized as true-negative (TN; UV<1.35). In 13 (21%) patients SMG visualized 22 true-positive (TP) malignant lesions: 2 residual VTT in scars, 1 newly defined BC in the contralateral breast and 18 regional LN metastases (6 axillary, 6 parasternal, 1 sub- and 5 supraclavicular). All 22 TP VTT lesions were imaged by scintigraphy using different tumor-seeking radiopharmaceuticals: 99mTc-MIBI - 17 (77%) and 99mTc- TF - 5 (23%) of the TP lesions. One false-positive (FP) (inflammation: UV>1.65) and one false-negative (FN) (UV<1.35) foci were found. Applying SMG±SPECT for BC restaging after surgery, the RT volume was changed in 13 of 62 (21%) patients.
  
  
  CONCLUSIONS
  SMG is a reliable imaging method for evaluating residual VTT, LN metastases or altered biological activity in the scars after BC surgery and could modify the irradiated volume, optimizing the therapeutic effect and minimizing RT side effects.
authors.affiliation: National Oncology Center Hospital, Department of Nuclear Medicine, Sofia, Bulgaria. piperkovae@gmail.com
authors.forename: E
authors.initials: E
authors.lastname: Piperkova
authors.forename: L
authors.initials: L
authors.lastname: Chavdarova
authors.forename: Z
authors.initials: Z
authors.lastname: Garanina
authors.forename: L
authors.initials: L
authors.lastname: Gocheva
authors.forename: V
authors.initials: V
authors.lastname: Parvanova
authors.forename: A
authors.initials: A
authors.lastname: Tzonevska
authors.forename: M
authors.initials: M
authors.lastname: Dimitrova
mesh_terms: D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D018270:Carcinoma, Ductal, Breast / Q000000981:diagnostic imaging / Q000473:pathology / Q000532:radiotherapy / Q000601:surgery; D005260:Female; D006801:Humans; D008875:Middle Aged; D009367:Neoplasm Staging; D009943:Organophosphorus Compounds; D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D017256:Technetium Tc 99m Sestamibi; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*
chemical_list: D009943:Organophosphorus Compounds; D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; C078700:technetium tc-99m tetrofosmin; D017256:Technetium Tc 99m Sestamibi