Annals of Nuclear Medicine (v.24, #10)

Ratio of standardized uptake value on PET helps predict response and outcome after chemotherapy in advanced non-small cell lung cancer by Kyoichi Kaira; Masahiro Endo; Koiku Asakura; Asuka Tsuya; Yukiko Nakamura; Tateaki Naito; Haruyasu Murakami; Toshiaki Takahashi; Nobuyuki Yamamoto (697-705).
The maximum standardized uptake value (SUVmax) on 18F-fluorodeoxyglucose-positron emission tomography (18F-FDG PET) within the primary tumor may predict outcome in patients with surgically resected non-small cell lung cancer (NSCLC). However, it remains uncertain whether the SUVmax of the primary tumor predicts outcome after chemotherapy in advanced NSCLC. Thus, we evaluated the ratio of SUVmax of the metastatic tumor to the primary tumor (M/P ratio) to determine whether it could be a useful marker in predicting response and outcome after chemotherapy in advanced NSCLC.Chemo-naïve patients with advanced NSCLC who had locoregional lymph nodes and/or distant metastases other than brain, were eligible for inclusion in this study. Response and survival were analyzed according to the SUVmax of primary tumor, the ratio of the SUVmax of the tumor to the mean SUV of the mediastinum (T/M ratio) and M/P ratio.One hundred and four consecutive patients were included in the retrospective study. Patients with high M/P ratio exhibited significantly lower response rates. The value of SUVmax and T/M ratio were not associated with the response to initial chemotherapy. In the univariate analysis, T/M ratio and SUVmax were significantly associated with poor outcome. However, the outcome of non-adenocarcinoma was unaffected by T/M ratio and SUVmax. Multivariate analysis confirmed that high M/P ratio was a significant independent factor predicting a poor outcome.High M/P ratio was associated with a poor response to initial chemotherapy and was a significant independent factor in predicting poor outcome in advanced NSCLC patients with metastatic tumors other than in brain.
Keywords: 18F-FDG PET; NSCLC; Advanced; Chemotherapy; Ratio of SUVmax

Decreased brain FDG uptake in patients with extensive non-Hodgkin’s lymphoma lesions by Kohei Hanaoka; Makoto Hosono; Taro Shimono; Kimio Usami; Yoshihiro Komeya; Norio Tsuchiya; Yuzuru Yamazoe; Kazunari Ishii; Youichi Tatsumi; Mitsugu Sumita (707-711).
Faint brain [18F]fluoro-2-deoxyglucose (FDG) uptake has sporadically been reported in patients with FDG-avid large or diffusely extended tumors. The purpose of this study was to investigate whether there is a correlation between massive tumor uptake and decreased brain uptake on FDG positron emission tomography/computed tomography (PET/CT).Sixty-five patients with histologically confirmed non-Hodgkin’s lymphoma who underwent FDG-PET/CT were enrolled. Thirty control subjects were also included to evaluate normal brain FDG uptake. PET/CT examinations were retrospectively reviewed. The volumetric regions of interest were placed over lesions by referring to CT and PET/CT fusion images to measure mean standardized uptake value (SUVavg). The products of SUVavg and tumor volume were calculated as total glycolytic volume (TGV). The maximum SUV (SUVmax) and SUVavg were measured in the cerebrum and cerebellum. The values of TGV and brain FDG uptake were plotted and analyzed with a linear regression method.In the lymphoma patients, there were statistically significant negative correlations between TGV and brain SUVs.Demonstrating a significant negative correlation between TGV and brain uptake validated the phenomenon of decreased brain FDG uptake. Diversion of FDG from the brain to the lymphoma tissue may occur during the FDG accumulation process. Recognition of this phenomenon prevents unnecessary further neurological examinations in such cases.
Keywords: PET; FDG; Brain uptake; Lymphoma

Enhanced washout of 99mTc-SESTAMIBI (MIBI) is found in the myocardium in patients after acute myocardial infarction (AMI) or in those with serious angina. However, a standard index for washout evaluation in ischemic heart disease has not been established. We approached the establishment of a standard index for regional washout in ischemic heart disease and report the evaluation results of a newly developed washout evaluation method.We made a polar map from short-axis myocardial SPECT images and developed a washout index (WO INDx) based on early and delayed images. The control group consisted of 10 healthy volunteers and a patient group of 43 patients with AMI or angina. Three nuclear cardiology specialists interpreted early and delayed images and visually graded the regional uptake of MIBI in 17 segments on a polar map, and the washout rate (WR) was compared with WO INDx.WO INDx and WR in the control group were 1.83 ± 1.95 and 35.59 ± 6.97, respectively. In the AMI cases the correlation of ejection fraction (EF) and WO INDx was −0.602, and the correlation of EF and WR was −0.346. The agreement between observers in the visual evaluation was high with excellent to moderate agreements. The ROC analysis was performed for WS2 with a washout score of 2 in the visual evaluation by Observers 1 to 3. The area under the ROC curve (AUC) was 0.934, 0.949 and 0.934 for WO INDx, respectively, and 0.681, 0.662 and 0.656 for WR, respectively, indicating that the AUC was higher for WO INDx. The sensitivity for WO INDx was 89.3, 88.9 and 96.3%, respectively, and the specificity was 88.2, 89.8 and 79.3%, respectively. The sensitivity for WR was 53.6, 52.8 and 51.9%, respectively, and the specificity was 87.5, 79.4 and 87.4%, respectively. These results suggested that WO INDx had higher reliability than WR in terms of sensitivity.The results suggested that the diagnosis using a new index, WO INDx, calculated from standardized percentage uptakes is more useful than that using the washout rate determined from the myocardial count in the MIBI washout evaluation.
Keywords: 99mTc-Sestamibi; Washout; Standard index

Risk stratification and prediction of cancer of focal thyroid fluorodeoxyglucose uptake during cancer evaluation by Bo Hyun Kim; Min A. Na; In Joo Kim; Seong-Jang Kim; Yong-Ki Kim (721-728).
Focal thyroid incidentaloma by F-18 2-deoxy-2-F18-fluoro-d-glucose (FDG) positron emission tomography (PET) has been reported 1–4% of cancer patients and normal healthy population, with a risk of cancer ranging 14–50%. The aim of this study was to investigate the prevalence of thyroid incidentaloma in F-18 FDG PET/CT and risk of cancer, usefulness of visual and SUVmax and SUVmean differentiating malignant nodules and to define the predictable variables.A total 159 patients with focal thyroid FDG incidentaloma during cancer evaluation with non-thyroid cancer were enrolled. After F-18 PET/CT, we analyzed the image visually and obtained semiquantitative indices.The incidence of focal FDG thyroid incidentaloma is 1.36% and cancer risk is 23.3%. The incidence of focal thyroid FDG uptake was significantly higher in women (2.88 vs. 0.31%; χ 2 = 136.4, p < 0.0001). Malignant thyroid incidentalomas show statistically significant higher value of SUVmax (malignant: median 4.53, range 2.1–12.0; benign: median 3.08, range 1.6–35, p = 0.0093). However, SUVmean have no statistical differences (malignant: median 2.17, range 1.77–3.19; benign: median 2.05, range 1.15–5.77, p = 0.0541). In ROC analyses, the optimal visual grades were >grade 3, and the optimal semiquantitative indices were 4.46 for SUVmax, 2.03 for SUVmean. The visual grade was superior to other variables for the differentiation malignant from benign thyroid incidentalomas. The size and visual grade was the potent predictor by logistic regression analysis.Focal thyroid FDG incidentalomas in non-thyroid cancer patients during evaluation have a high risk of malignancy. The size and visual grade are potential predictors for malignant thyroid incidentaloma.
Keywords: Thyroid incidentaloma; F-18 FDG PET/CT; SUV

Predictive value of Tc-99m galactosyl human serum albumin liver SPECT on the assessment of functional recovery after partial hepatectomy: a comparison with CT volumetry by Hideyuki Wakamatsu; Shigeki Nagamachi; Shogo Kiyohara; Seigo Fujita; Kiyohisa Kamimura; Shigemi Futami; Ryuichi Nishii; Motoaki Nagano; Kazuhiro Kondou; Masahiro Kai; Kazuo Chijiiwa; Shozo Tamura (729-734).
Predicting liver functional reserve is important before partial hepatectomy. However, it is difficult to predict using morphologic imaging modalities, such as CT and MRI. In this study, we assess the usefulness of galactosyl human serum albumin (GSA) scintigraphy in predicting liver function recovery.We performed 99mTc-GSA scintigraphy before operation in 56 patients. Each patient was administered 185 MBq of 99mTc-GSA by intravenous injection. Serial images were taken immediately after the administration for 40 min. SPECT images were obtained to make a functional map. We calculated the functioning parameter residual GSA-Rmax (GSA-RL) using analysis software developed by Dr. N. Shuke. In addition, we compared GSA-RL with the morphological parameter residual liver volume (RLV-CT) calculated by conventional CT and serum albumin (Alb) or cholinesterase (ChE). We analyzed the correlation between imaging parameters and the postoperative recovery periods of serum albumin (r-Alb) and cholinesterase (r-ChE) and the values at 1 and 3 months for serum albumin (1M-Alb, 3M-Alb) and cholinesterase (1M-ChE, 3M-ChE).We found significant correlations between GSA-RL and r-Alb, r-ChE, 1M-Alb, 3M-Alb, 1M-ChE and 3M-ChE, but not between RLV-CT and the same parameters.The GSA-RL calculated by 99mTc GSA-SPECT was a useful parameter for predicting postoperative liver function recovery that should be implemented before partial hepatectomy.
Keywords: 99mTc-GSA; Partial hepatectomy; Alb; ChE

Radionuclide arthrogram with SPECT/CT for the evaluation of mechanical loosening of hip and knee prostheses by Chong Ghee Chew; Peter Lewis; Fiona Middleton; Rene van den Wijngaard; Annie Deshaies (735-743).
To evaluate the value of SPECT/CT in radionuclide arthrogram (RNA) for the assessment of mechanical loosening of hip and knee prostheses.A retrospective audit of 117 RNA SPECT/CTs evaluated by a single reader––40 hips, (1 hemiarthroplasty) and 77 knees (12 unicompartmental). The detection of any radiotracer within the bone/prosthetic interface was deemed positive for loosening. The operative assessment of 29 hip and 44 knee prosthetic joints was known and used as the gold standard. A subsequent blinded reassessment of the planar images was performed and compared with the SPECT/CT results for 26 of the 29 hip and 42 of the 44 knee prostheses.The respective SPECT/CT versus planar results were as follows: hips––acetabular cup: sensitivity: 73 versus 0%; specificity: 71 versus 100%; positive predictive value: 62% versus indeterminate; negative predictive value: 80% versus 72% (p = 0.0044). Hips––femoral component: sensitivity: 78 versus 63%; specificity: 90 versus 94%; positive predictive value: 78 versus 83%; negative predictive value: 90 versus 85% (p = 0.2482). Knees––femoral component: sensitivity: 75 versus 17%; specificity 63 versus 97%; positive predictive value: 43 versus 67%; negative predictive value: 87 versus 74% (p = 0.0001). Knees––tibial component: sensitivity: 86 versus 63%; specificity: 86 versus 76%; positive predictive value: 55 versus 38%; negative predictive value: 97 versus 90% (p = 0.6831).For evaluation of mechanical loosening of the hip prosthesis SPECT/CT was significantly better than planar scanning for the acetabular cup, but not for the femoral stem. For evaluation of the knee prosthesis, a significant improvement was noted using SPECT/CT for the femoral component, and although superior results were also noted for the tibial component, statistical significance was not reached. Taking into account the limitations of this retrospective audit, the value of using RNA SPECT/CT appeared to lie in the exclusion of mechanical loosening.
Keywords: Hip; Knee; Prostheses; Arthrogram; SPECT/CT

Simultaneous PET–MR acquisition and MR-derived motion fields for correction of non-rigid motion in PET by Charalampos Tsoumpas; Jane E. Mackewn; Philip Halsted; Andrew P. King; Christian Buerger; John J. Totman; Tobias Schaeffter; Paul K. Marsden (745-750).
Positron emission tomography (PET) provides an accurate measurement of radiotracer concentration in vivo, but performance can be limited by subject motion which degrades spatial resolution and quantitative accuracy. This effect may become a limiting factor for PET studies in the body as PET scanner technology improves. In this work, we propose a new approach to address this problem by employing motion information from images measured simultaneously using a magnetic resonance (MR) scanner.The approach is demonstrated using an MR-compatible PET scanner and PET–MR acquisition with a purpose-designed phantom capable of non-rigid deformations. Measured, simultaneously acquired MR data were used to correct for motion in PET, and results were compared with those obtained using motion information from PET images alone.Motion artefacts were significantly reduced and the PET image quality and quantification was significantly improved by the use of MR motion fields, whilst the use of PET-only motion information was less successful.Combined PET–MR acquisitions potentially allow PET motion compensation in whole-body acquisitions without prolonging PET acquisition time or increasing radiation dose. This, to the best of our knowledge, is the first study to demonstrate that simultaneously acquired MR data can be used to estimate and correct for the effects of non-rigid motion in PET.
Keywords: Positron emission tomography; PET–MR; Motion fields; Motion correction

A simple test to determine the quality of your clinical PET images by Andre Dobbeleir; Hamphrey Ham; Ingeborg Goethals; Johan Keppens; Yves D’Asseler; Christophe Van de Wiele (751-757).
The objective of the study was to present a simple method for comparing clinical PET images to a set of increasing quality images. Those different quality images were obtained by varying the activity concentration and the acquisition time.Images of a Jaszczak phantom were acquired with scan times that were calculated with a spreadsheet application for a personal computer to obtain 500, 1000, 2000, 5000, 7000 and 9000 counts/4 mm3 voxel. During a 10-h period, each scan was repeated with longer acquisition times to obtain the same number of counts in the reconstructed images, but with lower count rate. On the second day, the study was repeated, putting the phantom in a water bath to simulate larger patients.The quality of the images obtained with the phantom in water was worse than without, as expected. Phantom data demonstrated clearly the effect of higher counts on image quality. Good quality images were obtained with counts above 5000 counts/voxel. Patient data can be situated to the phantom image set by comparing the counts per voxel and the activity concentration. The counts per voxel in all the regions of interest on patient data, with the exception of the brain, were at sub-optimal level leading to decreased image quality. It is clear that better image quality can be achieved mainly by incrementing the scan time. Our PET system, however, allows doubling our standard injected activity to obtain more image counts without significant contrast loss.This simple test can be performed at any PET center to situate the quality of routine clinical PET images in comparison to the optimal possible for that system.
Keywords: PET scan; Image quality; Scan time; Dose

Radioisotopes can be produced by reactors and accelerators. For certain isotopes there could be an advantage to a certain production method. However, nowadays many reports suggest, that useful isotopes needed in medicine, industry and research could be produced efficiently and dependence on reactors using enriched U-235 may be eliminated. In my view reactors and accelerators will continue to play their role side by side in the supply of suitable and economical sources of isotopes.