Joseph A. Thie

The Potential of F-18-FDG PET in Breast Cancer: Detection of Primary Lesions, Axillary Lymph Node Metastases, or Distant Metastases

This retrospective study was done to evaluate the utility of 2-[F-18]fluoro-2-deoxy-D-glucose positron emission tomography (F-18-FDG PET) in identifying primary and recurrent breast cancer and lymph node metastases. One hundred whole-body PET scans of 87 patients were reviewed. PET results obtained with F-18-FDG and an ECAT/EXACT-921 or an ECAT-931 (Siemens/CTI) were based on visual interpretation, or standardized uptake values (SUVs), related to histology and also compared to computerized tomography (CT) and mammography results. The sensitivity for PET in detecting primary (N = 35 studies) and recurrent breast cancer (N = 65 studies) was 96% and 85% with a specificity of 91% and 73%. The sensitivity for lymph node metastases at the time of initial diagnosis was 100% with a specificity of 100%. Quantitative SUV information did not improve the accuracy of F-18-FDG PET in identifying primary breast cancers. The results suggest that whole-body PET is useful in detecting recurrence or metastases, may be useful in detecting lymph node metastases prior to initial axillary lymph node dissection, but is less sensitive in excluding axillary lymph nodes metastases later in the course of the disease.

Cost Analysis of FDG PET for Managing Patients with Ovarian Cancer.

Monte Carlo simulation analysis was used to compare the cost of managing recurrent ovarian cancer patients with and without the use of positron emission tomography (PET) scanning. Assumptions in the management pathway were: (1) a positive PET scan led to either laparoscopy or laparotomy, followed by chemotherapy (true positive PET) or follow-up (false positive PET); (2) a negative PET scan resulted in continued follow-up (true negative PET) or laparotomy (false negative PET); and, (3) a laparotomy led to chemotherapy or follow-up. In this simulation, sensitivity and specificity of FDG PET for recurrent ovarian cancer varied from 72-91% (mean 83%) and 69-95% (mean 85%), respectively, as defined by the ROC curve. Using a prevalence rate of 30% for recurrent ovarian cancer, the mean PET false negative rate was 5%. Thus, when using PET to manage the diagnostic evaluation, the number of unnecessary laparotomies was reduced from 70% to 5%, with 35% of patients undergoing laparoscopy for recurrent disease instead of laparotomy. If laparotomy is used in place of laparoscopy, unnecessary surgery can be avoided in 30% of patients. Costs for procedures were based both on hospital charges, and Medicare reimbursement rates. Cost savings per patient ranged from

Optimizing Imaging Time for Improved Performance in Oncology PET Studies

1,941 to

Positron Emission Tomography (PET) with 1-Aminocyclobutane-1-[11C]carboxylic Acid (1-[11C]-ACBC) for Detecting Recurrent Brain Tumors

11,766, assuming that follow-up evaluation was similar for both groups. Estimated cost savings were due to the need for fewer surgical procedures when using PET in the diagnostic evaluation, the reimbursement rate scheme employed, and whether laparotomy or laparoscopy was used in the management algorithm for PET positive patients. In conclusion, FDG PET can reduce unnecessary invasive staging procedures and save health care costs when used appropriately in the management of patients with recurrent ovarian cancer.

A Weight Index for the Standardized Uptake Value in 2-Deoxy-2-[F-18]fluoro-d-glucose-Positron Emission Tomography

PURPOSEnThe potential for improving the diagnostic performance of static positron imaging tomography (PET) by judiciously choosing optimum post-injection imaging times is investigated.nnnPROCEDURESnDynamic and whole-body scan data, from 2-deoxy-2-[18F]fluoro-D-glucose (FDG) oncological studies, are analyzed for changing standardized uptake value (SUV) behavior with increasing post-injection times at either single- or multiple-bed positions. Model-based interpretations address d(SUV)/dt, shown to correlate with SUV, and the contrast ratio for a tumor and its surroundings. A method for correcting measurements to a standardized time is given.nnnRESULTSnBoth data and model-based equations suggest that starting data acquisition later than the average 55 +/- 15 (SD) minutes post-injection reported in the FDG literature can improve contrast ratios. Considerations for choosing an optimum time from a clinical standpoint are listed.nnnCONCLUSIONSnIt is concluded that the appropriate time for each particular protocol can be found with the aid of the information presented here. True optimization, however, remains a complex issue.

A statistical investigation of normal regional intra-subject heterogeneity of brain metabolism and perfusion by F-18 FDG and O-15 H2O PET imaging

This study was done to determine whether 1-[(11)C]ACBC PET has any advantages over 2-[(18)F]FDG PET, CT, or MRI in detecting recurrent brain tumors, and whether quantitative 1-[(11)C]ACBC PET information improves the accuracy of visual image interpretation.Twenty patients with recurrent brain tumor underwent dynamic PET. Images were analyzed by visual interpretation; in addition, standardized uptake values (SUVs) and Patlak values (k(1)*k(3)/k) were evaluated.1-[(11)C]ACBC identified 19/20 recurrent brain tumors, [18F]FDG 13/19, MRI 13/19, and CT 8/16. Based on SUVs, the average tumor-to-contralateral gray matter ratio of 1-[(11)C]ACBC was 5.0 and 0.5 for 2-[(18)F]FDG. Mean Patlak values of 1-[(11)C]ACBC were 0.044 +/- 0.047 for high and 0.034 +/- 0.026 for low grade tumors. However, visual interpretation was effective without quantitative PET data.1-[(11)C]ACBC, accurately detects recurrent tumors for selecting biopsy sites and treatment planning.

Standardized Uptake Value and Influx

IntroductionKnown errors in the standardized uptake value (SUV) caused by variations in subject weights W encountered can be corrected by lean body mass or body surface area (bsa) algorithms replacing W in calculations. However this is infrequently done. The aims of the work here are: quantify sensitivity to W, encourage SUV correction with an approach minimally differing from tradition, and show what improvements in the SUV coefficient of variation (cv) for a population can be expected.MethodsSelected for analyses were 2-deoxy-2-[F-18]fluoro-d-glucose (FDG) SUV data from positron emission tomography (PET) and PET/computed tomography (CT) scans at the University of Tennessee as well as from the literature. A weight sensitivity index was defined as −n=slope of ln(SUV/W) vs. lnW. The portion of the SUV variability due to this trend is removed by using the defined

Avoiding Second-Look Surgery and Reducing Costs in Managing Patients with Ovarian Cancer by Applying F-18-FDG PET.

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