***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Background Positron emission tomography ( PET ) imaging using [18F]fluorodeoxyglucose ( 18F-FDG ) is recognized to have a major role in oncological imaging . Over recent years there has been a steady increase in the use of gamma camera PET ( GCPET ) systems as these are less expensive than dedicated PET scanners and facilitate the full range of nuclear medicine imaging . However , there is ongoing debate about their application and usefulness in the management of oncological patients . Objectives To assess the feasibility of GCPET in a nuclear medicine department in a district general hospital remote from a cyclotron , compared with other imaging modalities in demonstrating disease in patients with large or locally advanced breast cancer . Methods 18F-FDG was transported by road from a production unit 100 miles from the imaging department . Twenty-five patients ( mean age 68 years ) with primary breast tumours measuring ≥20 mm on clinical examination were studied . All patients underwent triple assessment prior to PET imaging with an ADAC Solus camera with molecular coincidence detection capability . Histopathology was obtained in 20 cases following surgery . Results GCPET detected 24/25 primary breast tumours ( sensitivity 96 % ) . This compared with 22/25 ( 88 % ) for ultrasound and 15/25 ( 60 % ) for mammography . The lesion missed by PET was a grade 1 tumour , 8 mm in size . Conclusion In this pilot study GCPET has been shown to be feasible in a district general hospital , enabling a limited on-site PET imaging service to be provided . In the cases studied it was more sensitive than mammography or ultrasonography . GCPET may provide additional information that could be important in planning the management of some patients with breast cancer Background The role of positron emission tomography ( PET ) scanning in determining the extent of disease in patients with breast cancer has not been defined . We investigated the utility of 18F-2-fluoro-2-deoxy-D-glucose (FDG)-PET scanning compared with conventional imaging with computed tomographic scanning and bone scanning in determining the extent of disease in patients with high-risk , operable breast cancer . Methods This was a prospect i ve study of patients who presented to Memorial Sloan-Kettering Cancer Center for operative treatment of breast cancer . Eighty eligible patients were enrolled and underwent computed tomographic chest , abdomen , pelvis , and bone scans , followed by FDG-PET . Changes in treatment based on scan findings were recorded by the operating surgeons . Imaging findings were verified by biopsy or long-term follow-up . Results Eight ( 10 % ) of 80 patients were found to have metastatic disease that was seen on both conventional imaging and PET . Four additional patients ( 5 % ) had additional foci of disease on PET that affected treatment decisions . No patient had findings on conventional imaging alone . Conventional imaging studies result ed in a higher number of findings that generated additional tests and biopsies that ultimately had negative results ( 17 % vs. 5 % for PET ) . There was a statistically significant difference in specificity for PET compared with conventional imaging ( P = .01 ) . Conclusions Conventional imaging and PET were equally sensitive in detecting metastatic disease in patients with high-risk , operable breast cancer , but PET generated fewer false-positive results . FDG-PET scanning should be further studied in this setting and considered in the preoperative evaluation of selected patients with breast cancer We sought to prospect ively assess the diagnostic performance of a high-resolution positron emission tomography ( PET ) scanner using mild breast compression ( positron emission mammography [ PEM ] ) . Data were collected on concomitant medical conditions to assess potential confounding factors . At four centers , 94 consecutive women with known breast cancer or suspicious breast lesions received 18F-fluorodeoxyglucose ( FDG ) intravenously , followed by PEM scans . Readers were provided clinical histories and x-ray mammograms ( when available ) . After excluding inevaluable cases and two cases of lymphoma , PEM readings were correlated with histopathology for 92 lesions in 77 women : 77 index lesions ( 42 malignant ) , 3 ipsilateral lesions ( 3 malignant ) , and 12 contralateral lesions ( 3 malignant ) . Of 48 cancers , 16 ( 33 % ) were clinical ly evident ; 11 ( 23 % ) were ductal carcinoma in situ ( DCIS ) , and 37 ( 77 % ) were invasive ( 30 ductal , 4 lobular , and 3 mixed ; median size 21 mm ) . PEM depicted 10 of 11 ( 91 % ) DCIS and 33 of 37 ( 89 % ) invasive cancers .  PEM  was positive in 1 of 2 T1a tumors , 4 of 6 T1b tumors , 7 of 7 T1c tumors , and 4 of 4 cases where tumor size was not available ( e.g. , no surgical follow-up ) .  PEM sensitivity for detecting cancer was 90 % , specificity 86 % , positive predictive value ( PPV ) 88 % , negative predictive value ( NPV ) 88 % , accuracy 88 % , and area under the receiver-operating characteristic curve ( Az ) 0.918 . In three patients , cancer foci were identified only on PEM , significantly changing patient management . Excluding eight diabetic subjects and eight subjects whose lesions were characterized as clearly benign with conventional imaging ,  PEM sensitivity was 91 % , specificity 93 % , PPV 95 % , NPV 88 % , accuracy 92 % , and Az 0.949 when interpreted with mammographic and clinical findings . FDG PEM has high diagnostic accuracy for breast lesions , including DCIS The present study compared the diagnostic accuracy of fluorine-18 2-deoxy-2-fluoro-D-glucose positron emission tomography ( FDG-PET ) with conventional staging techniques . The differentiation between malignant and benign lesions and the detection of multifocal disease , axillary and internal lymph node involvement , and distant metastases were evaluated . One hundred and seventeen female patients were prospect ively examined using FDG-PET and conventional staging methods such as chest X-ray , ultrasonography of the breast and liver , mammography and bone scintigraphy .  All patients were examined on a modern full-ring PET scanner . Histopathological analysis of resected specimens was employed as the reference method . The readers of FDG-PET were blinded to the results of the other imaging methods and to the site of the breast tumour . The sensitivity and specificity of FDG-PET in detecting malignant breast lesions were 93 % and 75 % respectively . FDG-PET was twofold more sensitive ( sensitivity 63 % , specificity 95 % ) in detecting multifocal lesions than the combination of mammography and ultrasonography ( sensitivity 32 % , specificity 93 % ) . Sensitivity and specificity of FDG-PET in detecting axillary lymph node metastases were 79 % and 92 % ( 41 % and 96 % for clinical evaluation ) . FDG-PET  correctly indicated distant metastases in seven patients . False-positive or false-negative findings were not encountered with FDG-PET .  Chest X-ray was false-negative in three of five patients with lung metastases . Bone scintigraphy was false-positive in four patients . Three patients were upstaged since FDG-PET detected distant metastases missed with the st and ard staging procedure . It is concluded that , compared with the imaging methods currently employed for initial staging , FDG-PET is as accurate in interpreting the primary tumour and more accurate in screening for lymph node metastases and distant metastases . Due to a false-negative rate of 20 % in detecting axillary lymph node metastases , FDG-PET can not replace histological evaluation of axillary status BACKGROUND The aim of this work is to assess the diagnostic value of positron emission tomography ( PET ) with 18F-fluorodeoxyglucose ( FDG ) , in the early detection of tumour recurrence in already treated breast cancer patients in apparent complete remission and with a progressive elevation of tumour markers CEA and /or CA 15.3 without any other clinical or instrumental signs of relapses . METHODS The author studied 45 women ( mean age 58+/-12 , range 35 - 80 years ) with histological diagnosis of breast cancer who underwent a tumour marker-guided whole body FDG-PET .  All patients were in remission , without any other clinical or instrumental signs of relapses , except for the progressive elevation of CA 15.3 and /or CEA , tested during the follow-up . FDG-PET results were controlled by pathology when histological sampling was possible , by other conventional imaging modalities ( US , X-rays , CT , MRI ) and /or by clinical follow-up up to 12 months at least . RESULTS FDG-PET findings were evaluated in 38 patients : 27 result ed positive . Among these 27 PET positive patients 24 were true positive and 3 false positive . Tumour marker guided FDG-PET was also able to discover 3 unknown neoplasms not visualized by other modalities . PET revealed 54 sites of intense focal FDG uptake . The anatomical distribution of these sites was 19 skeleton , 18 lymph node basins , 5 liver , 5 pelvic region , 1 lung , 1 pericardium , 1 pleura , 1 contralateral breast , 2 peritoneum and 1 thyroid bed . Forty-eight of these 54 sites of FDG accumulation were confirmed to be metastases . FDG-PET result ed negative in 11 patients and only in 2 of them the other diagnostic modalities were able to discover metastatic lesions ; we had 9 true negative and 2 false positive RESULTS . On the basis of our investigation the performances of tumour marker guided FDG-PET per patient are as follows : sensitivity 92 % ( 24/26 ) , specificity 75 % ( 9/12 ) , positive predictive value 89 % ( 24/27 ) , negative predictive value 82 % ( 9/11 ) , accuracy 87 % ( 33/38 ) . CONCLUSIONS This study demonstrated the clinical utility of tumour marker-guided PET in the follow-up of breast cancer patients . This diagnostic approach allowed to modify the clinical management in those patients in whom a tumor relapse or unexpected primary neoplasm was discovered RATIONALE AND OBJECTIVES The authors performed this study to determine the feasibility of using quantitative 2-[fluorine-18]fluoro-2-deoxy-D-glucose ( FDG ) positron emission tomography ( PET ) to monitor the response of breast cancer bone metastases to therapy . MATERIAL S AND METHODS Twenty-four women with stage IV bone-dominant breast carcinoma were included in this study . Whole-body FDG PET imaging was performed at serial time points during the course of therapy . FDG PET scans were interpreted quantitatively by using the maximum st and ard uptake value ( SUV ) of the most conspicuous bone lesion at baseline FDG PET . PET results were compared to the overall assessment of response ( response , stable disease , progressive disease ) with a combination of conventional imaging , change in tumor marker values , and subjective symptom changes by experienced medical oncologists blinded to the findings at FDG PET . Changes in FDG SUV were also correlated quantitatively to the changes in a particular tumor marker ( CA 27.29 ) . RESULTS The changes in FDG SUV with therapy showed correlation with the overall clinical assessment of response ( P < .01 ) . The percentage change in FDG uptake with therapy showed strong correlation with the percentage change in tumor marker value ( P < .01 ) . CONCLUSION Preliminary results indicate that serial whole-body FDG PET can help quantitatively assess the response of breast cancer bone metastases to therapy . Prospect i ve trials are needed to further investigate its accuracy BACKGROUND Although axillary lymph node status is an important prognostic factor and axillary dissection is regarded as the gold st and ard for staging , it requires radical surgery which is accompanied by considerable postoperative problems such as lymphedema . This study was carried out to evaluate the diagnostic accuracy of preoperative positron emission tomography ( PET ) and intraoperative frozen biopsy of sentinel lymphadenectomy ( SLND ) in detecting axillary lymph node metastasis . METHODS We studied 18 patients who had preoperative PET and SLND for breast cancer in the Department of Surgery at Samsung Medical Center . They all had preoperative PET with a radiolabeled glucose analogue ( [18F]FDG ) to visualize primary tumors and metastatic nodes . Isosulphan blue dye was used for intraoperative SLND . Frozen and permanent biopsies were then compared after full axillary dissection . RESULTS In 18 cases , six had positive metastatic nodes in the permanent biopsy of full axillary dissection but were negative in three cases by preoperative PET . There was one false negative result by frozen biopsy of SLND which was later shown to be positive by permanent biopsy . The sensitivity and specificity of SLND and PET  for detecting axillary node metastasis were 83 , 100 % and 50 , 100 % , respectively . CONCLUSION Although both methods are good for axillary nodal status , the intraoperative frozen biopsy result of SLND was 
    Output:
    
FDG-PET does not appear to be sufficiently accurate to be used in isolation for ruling out the presence of a primary tumour .
In lymph gl and staging , FDG-PET does not appear to be accurate enough to detect occult axillary metastases or micrometastases ( sensitivity 20 and 50 % , respectively ) ; sentinel node biopsy is required for confirmation .
In the detection of bone metastases , FDG-PET should be complemented with other tests such as  bone gammagraphy  or  SPECT .
The assessment of response to chemotherapy , there seems to be no uniform criterion for establishing a st and ardized uptake value ( SUV ) for FDG that would allow responders and non-responders to be distinguished .
Conclusions FDG-PET is insufficiently sensitive to rule out small primary tumours .
Due to the high number of false positives returned , it can not replace axillary dissection in axillary lymph gl and staging .
A complete biochemical response identified by FDG-PET should not be relied upon to mean an absence of disease since the technique can not detect residual microscopic elements