Examination of iatrogenic FDG accumulation after COVID-19 vaccination.

PURPOSE: This study aimed to investigate the frequency of COVID-19 vaccine-induced reactive change and potential factors including blood type correlated with increased FDG uptake on positron emission tomography (PET)/computed tomography (CT). MATERIALS AND METHODS: We evaluated 284 patients who underwent PET/CT between June and September 2021 and had a known history of COVID-19 vaccination. Information on the injection site, vaccine type, and adverse reactions was obtained. We visually assessed the presence or absence of accumulation in the axillary and supraclavicular lymph nodes and the deltoid muscles. We measured the maximum standardized uptake value (SUVmax) using semi-quantitative analysis. RESULTS: Our study included 158 males and 126 females aged 16-94. The median time between vaccination and PET/CT was 9 and 42 days for patients who had received their first and second doses, respectively. We observed axillary lymph node accumulation, supraclavicular lymph node accumulation, and deltoid muscle accumulation in 98 (SUVmax 1.07-25.1), nine (SUVmax 2.28-14.5), and 33 cases (SUVmax 0.93-7.42), respectively. In cases with axillary lymph node (P = 0.0057) or deltoid muscle (P = 0.047) accumulation, the shorter the time since vaccination, the higher the FDG accumulation. Patients with axillary lymph node accumulation were significantly younger (P < 0.0001) and had a significantly higher frequency of adverse reactions such as fever (P < 0.0001) and myalgia (P = 0.002). No significant relationship was observed between blood type and the frequency of FDG accumulation. Logistic regression analysis also showed that age, gender, days since vaccination, and adverse reactions such as fever and myalgia were important factors for axillary lymph node accumulation. CONCLUSION: Our study found that FDG accumulation in the axillary lymph nodes and deltoid muscle was higher within a shorter time after vaccination, and axillary lymph node accumulation was higher in young patients, females, and those with adverse reactions of fever and myalgia. No significant relationship was observed between blood type and the frequency of FDG accumulation. Confirming the vaccination status, time since vaccination, and the presence of adverse reactions before PET may reduce false positives.

Pharmacokinetics of single dose radium-223 dichloride (BAY 88-8223) in Japanese patients with castration-resistant prostate cancer and bone metastases.

OBJECTIVE: This open-label, non-randomized, phase I study examined the pharmacokinetics (PK) and radiation dosimetry of a single dose of radium-223 in Japanese patients with castration-resistant prostate cancer (CRPC) and bone metastases. METHODS: Six male Japanese patients (mean age 72.5 years, range 65-79 years) with histologically or cytologically confirmed stage IV adenocarcinoma of the prostate were recruited. A single IV dose of radium-223 was delivered intravenously (IV) via slow bolus over a 2-5 min period: Cohort 1 received 50 kBq/kg and Cohort 2 received 100 kBq/kg. RESULTS: Following IV injection, radium-223 was rapidly eliminated from the blood in a multi-phasic manner. The fraction of the injected activity of radium-223 retained in the whole body 24 h following injection was 85 %. Biodistribution results showed initial bone uptake was 52 % (range 41-57 %). The maximum activity of radium-223 in the bone was observed within 2 h of dosing. Activity of radium-223 passed through the small intestine within 24 h. No activity was detected in other organs. The major radiation dose from radium-223 was found in osteogenic cells; calculated absorbed doses in osteogenic cells and in the red marrow were 0.76 Gy/MBq and 0.09 Gy/MBq, respectively. CONCLUSIONS: In Japanese patients with CRPC and bone metastases, radium-223 (IV) achieved maximum activity in the bone rapidly and passed through the intestine within 24 h, without signs of activity in other organs. The PK profile and absorbed radiation dose in organs and tissues in Japanese patients were similar to data from non-Japanese patients. Trial registration identification: NCT01565746.

Assessment of atherosclerosis in oncologic patients using ¹8F-fluoride PET/CT.

OBJECTIVES: The purpose of this study was to evaluate the prevalence, distribution, and relationship of (18)F-fluoride uptake and arterial calcification in oncologic patients using (18)F-fluoride PET/CT. METHODS: Image data obtained from 29 oncologic patients undergoing whole-body (18)F-fluoride PET/CT were evaluated retrospectively. Arterial wall (18)F-fluoride uptake and calcification were analyzed both quantitatively and semiquantitatively in 8 patients with arterial (18)F-fluoride uptake. RESULTS: Arterial (18)F-fluoride uptake was observed at 35 lesions in 8 (28 %) of the 29 patients, and calcification was observed at 345 lesions in the same patients. Five of the 8 patients had prostate cancer, and the remaining patients had hepatocellular carcinoma or malignant melanoma. In these 8 patients, the prevalence of both (18)F-fluoride uptake and calcification was highest in the abdominal aorta, followed by the descending thoracic aorta and the aortic arch. Colocalization of radiotracer accumulation and calcification could be observed in the 32 lesions (91 %) with arterial (18)F-fluoride uptake, and only the 3 lesions (9 %) with arterial (18)F-fluoride uptake were not colocalized with arterial calcification. The presence of both arterial radiotracer uptake and calcification was significantly associated with advancing age (P < 0.01). CONCLUSION: Our results suggest that (18)F-fluoride PET/CT might be a useful modality for detecting active mineral deposition sites of atherosclerosis in oncologic patients.

18F-Fluoride PET/CT allows detection of hyperostosis and osseous involvement in meningioma: initial experience.

PURPOSE: The present study was conducted to assess the diagnostic performance of (18)F-fluoride PET/CT in evaluating hyperostosis and osseous involvement in patients with meningioma. PATIENTS AND METHODS: Thirty-four patients with meningioma (mean age, 61 years) underwent (18)F-fluoride PET/CT before surgery. In 24 patients (71%), (18)F-FDG PET/CT was also given before surgery, and the results were compared. The images were reviewed by 2 board-certified nuclear medicine specialists who were unaware of any clinical information and a consensus was reached. Uptake patterns and measurements of tracers were compared with pathological findings from resected specimens, with hyperostosis and osseous involvement as the reference standard. RESULTS: There were 27 grade I tumors (79%) and 7 grade II tumors (21%). The primary tumor focus was identified in each patient using both (18)`F-fluoride PET/CT and (18)F-FDG PET/CT, but there were no significant correlations in the degree of uptake between the 2 tracers. The SUV(max), SUV(max) corrected for lean body mass (SUL(max)), and tumor metabolic volume (TMV) for (18)F-fluoride and (18)F-FDG were greater in grade II tumors than in grade I tumors. Hyperostosis and osseous involvement was identified in 12 tumors (38%). The SUV(max), SUL(max), and TMV of tumors visualized with (18)F-fluoride PET/CT were greater in tumors with hyperostosis and osseous involvement than in those without (P = 0.005, P = 0.003, and P = 0.006, respectively). In contrast, the SUV(max), SUL(max), and TMV of tumors visualized with (18)F-FDG PET/CT were similar regardless of hyperostosis or osseous involvement. CONCLUSIONS: (18)F-fluoride PET/CT may improve detection of hyperostosis and osseous involvement in patients with meningioma.

Biodistribution and radiation dosimetry of [¹8F]-5-fluorouracil.

PURPOSE: To estimate the radiation dose and biodistribution of (18)F-5-fluorouracil ([(18)F]-5-FU) from positron emission tomography/computed tomography (PET/CT) data, and to extrapolate mouse data to human data in order to evaluate cross-species consistency. METHODS: Fifteen cancer patients (head and neck cancer (n=11), colon cancer (n=4)) were enrolled. Sequential PET/CT images were acquired for 2h after intravenous administration of [(18)F]-5-FU, and the percent of the injected dose delivered to each organ was derived. For comparison, [(18)F]-5-FU was administered to female BALB/cAJcl-nu/nu nude mice (n=19), and the percent of the injected dose delivered to mouse organs was extrapolated to the human model. Absorbed radiation dose was calculated using OLINDA/EXM 1.0 software. RESULTS: In human subjects, high [(18)F]-5-FU uptake was seen in the liver, gallbladder and kidneys. The absorbed dose was highest in the gallbladder wall. In mice, the biodistribution of [(18)F]-5-FU corresponded to that of humans. Estimated absorbed radiation doses for all organs were moderately correlated, and doses to organs (except the gallbladder and urinary bladder) were significantly correlated between mice and humans. The mean effective [(18)F]-5-FU dose was higher in humans (0.0124mSv/MBq) than in mice (0.0058mSv/MBq). CONCLUSION: Biodistribution and radiation dosimetry of [(18)F]-5-FU were compared between humans and mice: biodistribution in mice and humans was similar. Data from mice underestimated the effective dose in humans, suggesting that clinical measurements are needed for more detailed dose estimation in order to ensure radiation safety. The observed effective doses suggest the feasibility of [(18)F]-5-FU PET/CT for human studies.

Role of 18F-fluoride PET/CT in the assessment of multiple myeloma: initial experience.

PURPOSE: The aim of this study was to report our early experience with (18)F-fluoride PET/CT for detecting lesions and evaluate the usefulness of this modality in the assessment of multiple myeloma (MM). MATERIALS AND METHODS: (18)F-fluoride PET/CT and (99m)Tc-MDP bone scintigraphy (BS) studies from 7 myeloma patients (4 male and 3 female, mean age 55 years) diagnosed according to standard criteria were reviewed retrospectively. Two reviewers visually and quantitatively analyzed the images and recorded their findings after reaching a consensus. Diagnostic certainty regarding the presence or absence of myeloma lesions was evaluated according to the reference standard consisting of whole-body magnetic resonance imaging and whole-body X-ray. RESULTS: A total of 93 affected areas were definite according to the reference standard. Of these, 83 affected areas (89 %) were identified on (18)F-fluoride PET/CT, whereas 54 affected areas (58 %) were found on BS. Mean SUVmax in the affected areas was 9.8 ± 3.2 (standard deviation) ranging from 5.0 to 21.2. A total of s17 lesions with bone fracture were also detected by (18)F-fluoride PET/CT and 2 lesions (12 %) were negative on BS. CONCLUSION: Our result showed that (18)F-fluoride PET was a possible modality to detect areas of lesions in patients with MM.

Power Doppler ultrasonography is useful for assessing disease activity and predicting joint destruction in rheumatoid arthritis patients receiving tocilizumab--preliminary data.

To evaluate the responsiveness of power Doppler ultrasonography (PDUS) in comparison with conventional measures of disease activity and structural damage in rheumatoid arthritis (RA) patients receiving tocilizumab (TCZ). Seven RA patients with active arthritis were enrolled in the study and prospectively monitored for 12 months. They were treated with TCZ (8 mg/kg) every 4 weeks as monotherapy or in combination with disease-modifying antirheumatic drugs (DMARDs). Clinical, laboratory, and ultrasound examinations were conducted at baseline, 1, 3, 6, 9, and 12 months. Power Doppler (PD) signals were graded from 0 to 3 in 24 joints, and total PD score was calculated as the sum of scores of individual joints. One-year radiographic progression of the hands was estimated by using Genant-modified Sharp scoring. The averages of the clinical parameters rapidly improved, and all patients achieved good response within 6 months based on standard 28-joint Disease Activity Score (DAS28). Although the average total PD score declined in parallel with clinical improvement, radiography of the hands showed progression of destruction in the joints where PD signals remained, even among clinical responders. ΔSharp score correlated with the time-integrated value (TIV) of total PD scores (Δtotal Sharp score: r = 0.77, P = 0.04; Δerosion: r = 0.78, P = 0.04; Δjoint-space narrowing (JSN): r = 0.75, P = 0.05), but not with TIVs of clinical parameters including DAS28. PDUS can independently evaluate disease activity in RA patients receiving TCZ and is superior to DAS28, especially in predicting joint destruction.

Age-related changes in pre- and postmenopausal women investigated with 18F-fluoride PET--a preliminary study.

OBJECTIVE: To evaluate the relationship between age and regional skeletal uptake at sites consisting of either predominantly trabecular or cortical bone using (18)F-fluoride positron emission tomography (PET) in pre- and postmenopausal women. MATERIALS AND METHODS: Thirty-two women (40.6 ± 12.3 years; age range 25-72 years) were assigned to one of two groups: group 1 comprised 22 premenopausal women (33 ± 6.5 years; age range 25-48 years) and group 2 comprised 10 postmenopausal women (56 ± 6.7 years; age range 49-72 years). The maximum standardized uptake value (SUVmax) was determined from the lumbar spine and the humeral shaft. Student's t-test for each unpaired dataset was used to evaluate statistical differences between the two groups. The SUVmax values for the humeral shaft and the lumbar spine were compared with aging. RESULTS: The SUVmax (mean ± SD) was 1.2 ± 0.5 in the humeral shaft and 4.7 ± 1.0 in the lumbar spine. The SUVmax in the humeral shaft correlated significantly with advancing age (r = 0.67, P < 0.01). The SUVmax in the lumbar spine declined significantly with advancing age (r = -0.50, P < 0.01). The humeral shaft of women in group 1 exhibited a significantly lower SUVmax compared to that in group 2 (1.1 ± 0.4 versus 1.6 ± 0.6; P < 0.05). On the other hand, the lumbar spine of women in group 1 exhibited a significantly higher SUVmax compared to that in group 2 (5.1 ± 0.7 versus 4.0 ± 1.1; P < 0.05). The mean SUVmax in the lumbar spine was 2.5 times greater than that in the humeral shaft in group 2. CONCLUSION: Semiquantitative analysis with (18)F-fluoride PET might be a useful tool for analyzing age-related changes in pre- and postmenopausal women.

Use of 18F-fluoride PET to determine the appropriate tissue sampling region for improved sensitivity of tissue examinations in cases of suspected periprosthetic infection after total hip arthroplasty.

BACKGROUND AND PURPOSE: The accurate diagnosis of periprosthetic infection requires assessment of intraoperative tissues. These must be sampled from the appropriate sites. We used (18)F-fluoride positron emission tomography (PET) to identify sites of inflammation in order to improve the sensitivity of histopathology, microbiological culture, and real-time PCR in total hip arthroplasty (THA) patients. PATIENTS AND METHODS: 23 THA patients (23 hips) scheduled for revision surgery (the revision group) and 17 uninfected THA patients (23 hips; control group) were enrolled. Uptake was classified into major, minor, and no uptake. To evaluate the association between the (18)F-fluoride uptake and intraoperative tissue results in the revision group, we calculated their sensitivity on each of the major, minor, and no-uptake sides. RESULTS: 17 revision patients showed major uptake and all were diagnosed as having septic loosening from intraoperative tissue results. Minor uptake was observed in the other 6 revision patients and all were diagnosed as having aseptic loosening. Apart from 3 cases that showed minor uptake regions, control subjects showed no uptake. In the revision group, the sensitivities of histopathology, microbiological culture, real-time PCR separately and also in combination were 0.78, 0.58, 0.96, and 0.96, respectively, on the major (18)F-fluoride uptake sides, 0.0, 0.0, 0.1, and 0.1 on the minor-uptake sides, and 0, 0, 0.18, and 0.18 on the no-uptake sides. INTERPRETATION: Our findings suggest that preoperative assessment of major uptake of (18)F-fluoride markedly improves the accuracy of tissue sampling, and thus the sensitivity of subsequent tissue examinations. More definitive diagnosis of periprosthetic infection is therefore possible.

F-18 FDG uptake patterns and disease activity of collagen vascular diseases-associated arthritis.

PURPOSE: The purpose of the present study was to investigate F-18 FDG uptake patterns, and to see whether joint F-18 FDG uptake reflected disease activity in patients with collagen vascular diseases (CVD)-associated arthritis. MATERIALS AND METHODS: A total of 72 patients with CVD-associated arthritis and 30 control subjects who underwent F-18 FDG PET or PET/CT were retrospectively investigated. PET images of 12 major joints, 7 minor joints, and extra-articular accumulation were assessed. We investigated F-18 FDG uptake patterns and the relationships between the degree of F-18 FDG uptake and distribution, clinical symptoms, and laboratory test results. RESULTS: Remitting seronegative symmetric synovitis with pitting edema syndrome, mixed connective tissue disease, rheumatoid arthritis, and systemic sclerosis tended to show strong and multiple joint F-18 FDG uptake. F-18 FDG uptake was found in bone marrow (86%) and/or spleen (57%) in 7 patients with adult-onset Still disease. The maximum standardized uptake value (SUVmax) correlated with the counts of erythrocyte sedimentation rate, matrix metalloproteinase-3, IgG, and IgA. Joint swelling had a positive association with SUVmax. Multiple logistic regression analyses revealed that factor associated with increased SUVmax of the joint was joint swelling (P = 0.005). CONCLUSIONS: The degree of joint F-18 FDG uptake may contribute to predict active inflammatory process of the joint. In addition, F-18 FDG uptake patterns may have a potential which helps differential diagnosis of CVD-associated arthritis.

Assessment of tumor hypoxia by 62Cu-ATSM PET/CT as a predictor of response in head and neck cancer: a pilot study.

OBJECTIVE: In radiotherapy and chemotherapy tumor hypoxia is recognized as a major obstacle to effective treatment. We undertook a pilot study in patients with locally advanced head and neck cancer to determine whether there is a relationship between tumor uptake of (62)Cu-ATSM and response to chemoradiotherapy. METHODS: Seventeen patients were studied using PET/CT with (62)Cu-ATSM and (18)F-FDG prior to the initiation of radiotherapy and chemotherapy. All patients had locally advanced head and neck cancer (stage III or IV). Tumor uptake in all patients was measured by region of interest analysis using the maximal standardized uptake value (SUVmax). A total dose of 50.4-70.2 Gy (median 70.2 Gy) was delivered in 29-39 fractions (median 39 fractions) to tumor. In patients with (non CR) and without (CR) residual/recurrent tumors at 2-year post irradiation, the statistical significance of the differences in tumor (62)Cu-ATSM SUVmax, T/M ratio, (18)F-FDG SUVmax and tumor volume were analyzed using Student's t test and Welch test. The relationship between clinical outcome and (62)Cu-ATSM/(18)F-FDG uptake patterns was analyzed using Kruskal-Wallis test. The correlation between SUVmax of (62)Cu-ATSM and (18)F-FDG was compared by Spearman's rank correlation test. RESULTS: Two of the 17 patients that were enrolled in our study were excluded from the final analysis. Of the 15 remaining patients, 9 patients were free of disease and 6 patients had residual/recurrent tumors. The SUVmax differed significantly (p < 0.05) between patients with or without residual/recurrent tumor on (62)Cu-ATSM PET/CT. Six of the 10 patients with tumors SUVmax >5.00 had residual/recurrent tumor, whereas all of the 5 patients with tumors SUVmax <5.00 were free of disease. There was no significant difference in FDG uptake between patients with and without residual/recurrent tumor. CONCLUSIONS: The results of this pilot study suggested that (62)Cu-ATSM uptake may be a predictive indicator of tumor response to chemoradiotherapy in patients with locally advanced head and neck cancer.

The potential of FDG-PET/CT for detecting prostate cancer in patients with an elevated serum PSA level.

PURPOSE: The aim of this study is to evaluate the potential and limitation of FDG-PET/CT for detecting prostate cancer in subjects with an elevated serum prostate-specific antigen (PSA) level. Although [¹8F]-2-fluoro-2-deoxyglucose positron emission tomography (FDG-PET) has limited value in detecting prostate cancer, the potential of PET/CT has not been precisely evaluated, since positron emission tomography/computed tomography (PET/CT) provides accurate localization of functional findings obtained by PET. METHODS: Subjects with an increasing PSA level suggestive of prostate cancer were enrolled in this study. FDG-PET/CT was performed prior to prostate biopsy and the findings were compared with the pathological results. RESULTS: Fifty subjects with an elevated serum PSA level took part in this study. The sensitivity, specificity and positive predictive value (PPV) of FDG-PET/CT in the prostate were 51.9% (27/52 areas), 75.7% (112/148 areas) and 42.9% (27/63 areas), respectively; those in the peripheral zone were 73.3% (22/30 areas), 64.3% (45/70 areas) and 46.8% (22/47 areas), respectively; and those in the central gland were 22.7% (5/22 areas), 85.9% (67/78 areas) and 31.3% (5/16 areas), respectively. The estimated cut-off values according to the highest odds ratio (OR) were age of 70 years [OR: 7.00, 95% confidence interval (CI): 1.89-25.93] and a PSA value of 12.0 ng/ml (OR: 10.77, 95% CI: 2.78-41.74). The FDG-PET/CT could potentially detect cancer with 80.0% sensitivity and 87.0% PPV in cases with a Gleason score of 7 or greater. CONCLUSION: FDG-PET/CT was appropriate for detecting peripheral zone prostate cancer in patients at more than an intermediate risk.

Optimum emission time in deep-inspiration breath-hold PET-CT: a preliminary result.

OBJECTIVE: The purpose of this study was to investigate optimum emission time of deep inspiration breath-hold (DIBH) positron emission tomography-computed tomography (PET-CT). METHODS: We collected 15 PET-CT data sets by adding data of every 10 s and acquisition time ranging from 10 s (1 x 10 s acquisition) to 150 s (15 x 10 s acquisition) for both of DIBH mode and free-breathing condition (continuous mode) in phantom study. The coefficient of variation (CV) of radioactivity concentration was compared to determine optimum emission time of PET-CT. We also compared images of DIBH mode and continuous mode to clarify the influence of diaphragmatic movement in clinical setting. RESULTS: The mean +/- SD of CV in DIBH mode was 1236.3 +/- 323.1. When compared with the CV at 120 s, the relative error of CV is within 10% at 110 s (0.204), 15% at 100 s (0.212), and 20% at 90 s (0.222), respectively. Optimum emission time greater than 90 s is required to obtain clinically available images in DIBH mode. In the clinical setting, the SUV of the lung base and measurements of uptake show little influence by respiration on DIBH PET-CT. CONCLUSIONS: Optimum emission time of DIBH technique greater than 90 s acquisition is preferable for clinical use.

PET assessment of disease activity in children with juvenile idiopathic arthritis.

BACKGROUND: The degree of 18-fluorodeoxyglucose (FDG) uptake is previously reported to correlate with physical examination and laboratory tests for evaluating disease activity in patients with rheumatoid arthritis. The clinical validity of (18)F-FDG positron emission tomography (PET) has not been evaluated in juvenile idiopathic arthritis (JIA). OBJECTIVE: To assess the relationship between (18)F-FDG PET uptake and disease activity in children with JIA. MATERIALS AND METHODS: A total of 560 joints in 28 children (mean age, 5.4 years; range, 1-16 years) with JIA who had undergone whole-body (18)F-FDG PET before treatment were retrospectively assessed clinically, biochemically and radiographically. PET images were assessed independently by two readers. We investigated the relationships between the degree of synovial (18)F-FDG uptake and radiographic and clinical symptoms and laboratory findings. RESULTS: Joint tenderness and swelling had a positive association with abnormal (18)F-FDG uptake in the joint [odds ratio (OR) 5.37, 7.12, respectively]. The standardized uptake value (SUV) max correlated with the neutrophil count, plasma C-reactive protein (CRP), erythrocyte sedimentation rate (ESR) and matrix metalloproteinase (MMP) 3. Joint erosion (OR, 6.17), soft-tissue swelling (OR, 3.77), major joints involvement (OR, 3.50), tenderness (OR, 5.22), and CRP concentration in plasma (OR, 1.81) were positively associated with SUVmax. CONCLUSION: The degree of (18)F-FDG uptake may be associated with the severity of synovitis in children with JIA.

A meta-analysis of (18)F-Fluoride positron emission tomography for assessment of metastatic bone tumor.

PURPOSE: The aim of this study was to assess the diagnostic performance of (18)F-Fluoride positron emission tomography (PET) or positron emission tomography/computed tomography (PET/CT) compared with bone scintigraphy (BS) planar or BS planar and single photon emission computed tomography (SPECT) in evaluating patients with metastatic bone tumor. MATERIALS AND METHODS: We performed a meta-analysis of all available studies addressing the diagnostic accuracy of (18)F-Fluoride PET, (18)F-Fluoride PET/CT, BS planar, and BS planar and SPECT for detecting the metastatic bone tumor. We determined sensitivities and specificities across studies, calculated positive and negative likelihood ratios, and drew summary receiver operating characteristic curves using hierarchical regression models. We also compared the effective dose and cost-effectiveness estimated by data from the enrolled studies between (18)F-Fluoride PET or PET/CT and BS planar or BS planar and SPECT. RESULTS: When comparing all studies with data on (18)F-Fluoride PET or PET/CT, sensitivity and specificity were 96.2% [95% confidence interval (CI) 93.5-98.9%] and 98.5% (95% CI 97.0-100%), respectively, on a patient basis and 96.9% (95% CI 95.9-98.0%) and 98.0% (95% CI 97.1-98.9%), respectively, on a lesion basis. The Az values of (18)F-Fluoride PET or PET/CT were 0.986 for the patient basis and 0.905 for the lesion basis, whereas those of BS or BS and SPECT were 0.866 for the patient basis and 0.854 for the lesion basis. However, the estimated effective dose and average cost-effective ratio were poorer for (18)F-Fluoride PET or PET/CT than those of BS planar or BS planar and SPECT. CONCLUSION: (18)F-Fluoride PET or PET/CT has excellent diagnostic performance for the detection of metastatic bone tumor, but the estimated effective dose and average cost-effective ratio are at a disadvantage compared with BS planar or BS planar and SPECT.

18F-fluoride uptake in bone metastasis: morphologic and metabolic analysis on integrated PET/CT.

OBJECTIVE: The aim of our study was to evaluate detectability of bone metastatic lesions and evaluate the correlation between (18)F-fluoride uptake patterns on positron emission tomography (PET) and morphologic changes on CT using integrated PET/CT. METHODS: We performed whole-body (18)F-fluoride PET/CT staging for 27 patients with known cancer. Tumor types comprised breast (n = 7), prostate (n = 7), and others (n = 13). A total of 154 uptake lesions were evaluated. Both tracer uptake patterns determined by (18)F-fluoride PET and morphologic patterns based on CT findings such as morphologic changes, involved locations, and grades scored using five-point scale were compared with histologic tumor subtypes and clinical laboratory data. RESULTS: CT patterns of metastatic lesion were lytic or unclassified in 26 lesions, sclerotic in 53 lesions, and mixed in 75 lesions. Multiple linear regression analysis revealed that metastatic bone lesions with high maximum standardized uptake value (SUVmax) tended to show sclerotic or mixed changes on CT (P < 0.0001), and were also distributed in bone cortex alone or both bone cortex and medulla (P < 0.0001). CONCLUSION: In patients with bone metastasis, the lesions with sclerotic or mixed changes or located in bone cortex alone or both bone cortex and medulla tend to show high SUVmax on (18)F-fluoride PET/CT.

Evaluation of response to multikinase inhibitor in metastatic renal cell carcinoma by FDG PET/contrast-enhanced CT.

PURPOSE: Multikinase inhibitor (MKI) is a promising drug for treatment of metastatic renal cell carcinoma (mRCC). We explained the usefulness of [¹8F]-2-fluoro-2-deoxyglucose positron emission tomography/contrast-enhanced computed tomography (FDG PET/CECT) for mRCC in evaluating the early response to MKI and in predicting progression-free survival (PFS). METHODS: Patients who planned MKI treatment for mRCC were included in this prospective study. FDG PET/CECT was performed before MKI treatment and after one cycle of MKI treatment. Evaluation of the response to MKI was assessed by PET according to the European Organization for Research and Treatment of Cancer, by CT according to the Response Evaluation Criteria in Solid Tumors and appearance of central hypoattenuation (CHA). RESULTS: Twelve patients were enrolled in the study. Equality of response evaluation between PET and CT was in 8 patients (partial response [PR]: 1, stable disease [SD]: 6, progressive disease [PD]: 1). Among the other 4 patients, PET showed 2 patients with PR and 2 patients with PD, in contrast to the CT finding of SD in all 4 patients. PFS according to PET response showed a statistically significant difference between PR and SD (P < 0.05) and between PR and PD (P < 0.05), but not between PR and SD (P = 0.083). Positive CHA in metastatic lesions after MKI treatment was confirmed in 8 patients. PFS with positive CHA was 233.8 days, while that without CHA was 75.0 days (P < 0.05). CONCLUSION: FDG PET/CECT shows potential for evaluating early treatment response to MKI in mRCC and for predicting PFS.

Multiple extra-articular synovial cysts complicated with rheumatoid arthritis.

Multiple extra-articular synovial cysts (MESC) are rarely complicated with various rheumatic diseases. We here first report a rheumatoid arthritis (RA) patient with MESC, which were extensively analyzed by a series of imaging techniques including fluorine-18-2-fluoro-D: -glucose positron emission tomography ((18)F-FDG-PET), magnetic resonance imaging (MRI), and ultrasonography. FDG uptakes in joint lesions with MESC were much higher than those reported in typical lesions of RA, suggesting that marked joint inflammation is implicated in the development of MESC.

SUV correction for injection errors in FDG-PET examination.

OBJECTIVE: Many studies have documented the clinical usefulness of standardized uptake values (SUV) for diagnosis. However, in the event of injection error, accurate measurements cannot be obtained if the radioactivity of fluorodeoxyglucose (FDG) leakage is not subtracted from the administered dosage. Here, a correction formula for radioactivity estimation that takes into account the radioactivity of FDG leakage was derived on the basis of a phantom experiment. Furthermore, to determine whether SUV could be accurately calculated by the correction formula, we performed a volunteer study. METHODS: Images were displayed by altering the conversion constant from 1.0, 0.1 to 0.01, and the range of correctable counts was verified on the basis of image inversion. To estimate the radioactivity of FDG leakage by imaging, the count of the leakage was measured, converted into a radioactivity concentration using a cross-calibration factor (CCF), and multiplied by volume, as measured by imaging. Three factors that markedly affect count, i.e., count rate performance, partial volume effect and crosstalk, were assessed in phantom studies in order to derive a correction formula. In addition, to clarify the accuracy of the correction formula, we attached to the right elbow. RESULTS: With a conversion constant of 0.1, there was no image inversion at or=28 mm Leakage radioactivity (MBq)=positron emission tomography (PET) radioactivity (MBq)x0.9. For leakages of >or=15 mm but <28 mm Leakage radioactivity (MBq)=PET radioactivity (MBq)x0.9x(0.0517xleakage size (mm)-0.4029). In a volunteer study with 10 MBq leakage, SUV recalculated using the formula achieved 99.97% correction, whereas with 100 MBq leakage, SUV achieved 67.5% resulting in poor correction. CONCLUSIONS: The present correction technique can accurately calculate SUV and could be useful for the clinical diagnosis of malignant tumors.

The roles of PET and PET/CT in the diagnosis and management of prostate cancer.

2-(18)F-fluoro-2-deoxy-D-glucose (FDG)-positron emission tomography (PET) imaging in prostate cancer is challenging because glucose utilization in well-differentiated prostate cancer is often lower than in other tumor types. Nonetheless, FDG-PET has a high positive predictive value for untreated metastases in viscera, but not lymph nodes. A positive FDG-PET can provide useful information to aid the clinician's decision on future management in selected patients who have low prostate-specific antigen levels and visceral changes as a result of metastases. On the other hand, FDG-PET is limited in the identification of prostate tumors, as normal urinary excretion of radioisotope can mask pathological uptake. Moreover, there is an overlap in the degree of uptake between prostate cancer, benign prostatic hyperplasia and inflammation. The tracer choice is also important. (11)C-choline has the advantage of reduced urinary excretion, and thus (11)C-choline PET may provide more accurate information on the localization of main primary prostate cancer lesions than MRI or MR spectroscopy. (11)C-choline PET is sensitive and accurate in the preoperative staging of pelvic lymph nodes in prostate cancer. A few studies are available but there were no PET or PET/CT studies with a large number of patients for tissue confirmation of prostate cancer; further investigations are required.