Combined Positron Emission Research Articles

Combined clinical and specific positron emission tomography/computed tomography-based radiomic features and machine-learning model in prediction of thymoma risk groups.

In this single-center study, we aimed to propose a machine-learning model and assess its ability with clinical data to classify low- and high-risk thymoma on fluorine-18 (18F) fluorodeoxyglucose (FDG) (18F-FDG) PET/computed tomography (CT) images. Twenty-seven patients (14 male, 13 female; mean age: 49.6 ± 10.2 years) who underwent PET/CT to evaluate the suspected anterior mediastinal mass and histopathologically diagnosed with thymoma were included. On 18F-FDG PET/CT images, the anterior mediastinal tumor was segmented. Standardized uptake value (SUV)max, SUVmean, SUVpeak, MTV and total lesion glycolysis of primary mediastinal lesions were calculated. For texture analysis first, second, and higher-order texture features were calculated. Clinical information includes gender, age, myasthenia gravis status; serum levels of lactate dehydrogenase (LDH), alkaline phosphatase, C-reactive protein, hemoglobin, white blood cell, lymphocyte and platelet counts were included in the analysis. Histopathologic examination was consistent with low risk and high-risk thymoma in 15 cases and 12 cases, respectively. The age and myasthenic syndrome were statistically significant in both groups (P = 0.039 and P = 0.05, respectively). The serum LDH level was also statistically significant in both groups (450.86 ± 487.07 vs. 204.82 ± 59.04; P < 0.001). The highest AUC has been achieved with MLP Classifier (ANN) machine learning method, with a range of 0.830 then the other learning classifiers. Three features were identified to differentiate low- and high-risk thymoma for the machine learning, namely; myasthenia gravis, LDH, SHAPE_Sphericity [only for 3D ROI (nz>1)]. This small dataset study has proposed a machine-learning model by MLP Classifier (ANN) analysis on 18F-FDG PET/CT images, which can predict low risk and high-risk thymoma. This study also demonstrated that the combination of clinical data and specific PET/CT-based radiomic features with image variables can predict thymoma risk groups. However, these results should be supported by studies with larger dataset.

The role of PET-CT with &lt;sup&gt;18&lt;/sup&gt;F-FDG in initial assessment of patients with carcinoma of unknown primary (CUP) in the head and neck

Introduction. Cancer metastases from an unknown primary origin (CUP) in the head and neck area include a large heterogeneous group of tumor formations, the primary localization of which could not be established even after a thorough diagnostic search. Combined positron emission computed tomography (PET-CT) with 18 F-FDG has a high level of detection of primary neoplasms as a result of simultaneous acquisition of precisely combined anatomical and functional images of the entire body. Objectives. 1. To evaluate the possibility of using PET-CT (positron emission tomography in combination with computed tomography) with 18 F-FDG (18-fluorodeoxyglucose) in patients with metastases from the CUP (carcinoma unknown primary) in the head and neck. To determine the effectiveness of PET-CT for the detection of primary tumor focus in patients with histologically verified diagnosis of CUP in the head and neck. To evaluate the contribution of the PET-CT technique in assessing the prevalence of the disease in patients diagnosed with head and neck cancer. Materials and methods. 134 patients diagnosed with CUP in the head and neck from September 2018 to March 2019 were included to this retrospective study: 35(26.1%) women and 99(73.9%) men, with the mean age of 61.9 ± 7.5 years. All patients underwent a biopsy from at least one metastatic lesion, and the malignant nature of the neoplasm was histologically verified. Before PET-CT with 18F-FDG, standard oncological evaluation was carried out to detect primary tumor. Results. Among 134 patients comprised the study, initial histological diagnoses were: squamous cell cancer (n = 82, 61.2%), melanoma (n = 5, 3.7%), undifferentiated carcinoma (n = 20, 15%), adenocarcinoma (n = 21, 15.6%) and undifferentiated malignant neoplasm (n = 6, 4.5%). With PET-CT with 18F-FDG, primary tumor location was revealed in 72 (54%) of the patients. New metastatic lesions were found in 60 (44.7%) of the patients. Change in the TNM stage was observed in 95(71%) of all cases after PET-CT with 18 F-FDG. It was associated both with the detection of the primary tumor and the identification of new metastatic foci. Conclusions. Use of PET-CT with 18 F-FDG allows to carry out oncological evaluation more precisely than the standard procedures in the majority of patients with CUP in the head and neck region. In a significant quota of cases, this method is in a position also to help to identify the primary tumor lesion, which, in turn, influences on strategy of treatment and also on the prognosis of disease. PET-CT with 18 F-FDG should be included to the protocol of radiological examination in patients with CUP in the head and neck anatomic area.

IPET-CT in inflammatory diseases of kidneys and bladder: diagnostic efficacy

Introduction. The incorporation of combined positron emission tomography-computed tomography (PET-CT) into clinical practice has significantly expanded the understanding of the pathogenesis of many diseases. Evidence-based data on the diagnostic efficacy in infectious and inflammatory diseases is increasing, making this imaging method very promising. Purpose of the study. To study the diagnostic efficacy of 18F-FDG PET-CT in various chronic inflammatory diseases of kidneys and bladder.Materials and methods. A retrospective study of the results of whole-body 18F-FDG PET-CT in 45 patients was carried out. Patients underwent an investigation at various times after surgical treatment of localized oncology of the anogenital zone at the T1N0M0 stage without the involvement of the genitourinary system. It was found that 24 patients had a history of chronic pyelonephritis and 21 patients had manifestations of radiation cystitis. Repeated PET/CT scans were performed after a course of therapy for inflammatory urological diseases to assess the treatment results of the underlying pathology.Results. The latent course of chronic renal failure was accompanied by a diffuse decrease in 18F-FDG metabolism in the renal parenchyma with its partial recovery after etiotropic therapy and urine sanitation. Hypermetabolism of 18F-FDG was detected in the bladder wall during manifestations of radiation cystitis, which was leveled during therapy and relief of urinary syndrome manifestations. Bacterial and radiation inflammation differed in molecular-cell responses to the pathogen, while the results of urinalysis, indicating the effectiveness of the treatment, coincided with the visual and digital indicators of the restoration of adequate energy metabolism in the studied tissues.Conclusions. Metabolism of 18F-FDG in the kidneys and bladder can objectively reflect the nature of inflammation and complement the data on the effectiveness of the treatment.

PATIENT DOSES IN WHOLE-BODY PET/CT EXAMINATIONS IN THE LARGEST TERTIARY HOSPITAL IN GREECE.

The purpose of this study was to determine the patient radiation dose in combined whole-body positron emission tomography/computed tomography (PET/CT) examinations performed in the largest tertiary hospital in Greece. Computed tomography dose index (CTDIvol), dose length product (DLP), weight, height and administered activity of 2-[18F] fluoro-2-deoxy-D-glucose values for PET/CT examinations were recorded in a sample of 1014 randomly selected patients. The mean (±standard deviation) and median (interquartile) CTDIvol values were equal to 5.5±2.4 and 4.8 (2.5) mGy, respectively. The respective DLP values were 483.3±212.4 and 426 (234.6) mGy·cm. For the administered activity, mean and median were equal to 363.9±68.3 and 361.6 (85.6) MBq. The mean administered activity per body weight was 4.8±0.6 and the median 4.8 (0.6) MBq/kg. The results of this survey are within the range of values reported in the literature and can be used as a standard of reference until national diagnostic reference levels are established for whole-body PET/CT procedures.

Correlated functional connectivity and glucose metabolism in brain white matter revealed by simultaneous MRI/positron emission tomography.

PurposeThere has been converging evidence of reliable detections of blood oxygenation level dependent (BOLD) signals evoked by neural stimulation and in a resting state in white matter (WM), within which few studies examined the relationship between BOLD functional signals and tissue metabolism. The purpose of the present study was to explore whether such relationship exists using combined functional MRI and positron emission tomography (PET) measurements of glucose uptake.MethodsFunctional and metabolic imaging data from 25 right‐handed healthy human adults (aged 18–23 years, 18 females) were analyzed. Measures, including average resting state functional connectivity (FC) with respect to 82 Brodmann areas, fractional amplitude of low‐frequency fluctuations (FALFF), and average fluorodeoxyglucose (FDG) uptake by PET, were computed for 48 predefined WM bundles. Pearson correlations across the bundles and 25 subjects studied were calculated among these measures. Linear mixed effects models were used to estimate the variance explainable by a predictor variable in the absence of inter‐subject variations.ResultsAnalysis of six separate imaging intervals found that average FC the bundles was significantly correlated with local FDG uptake (r = 0.25, p < 0.001), and the FC also covaried significantly with FALFF (r = 0.41, p < 0.001). When random effects from inter‐subject variations were controlled, these correlations appeared to be medium to strong (r = 0.41 for FC vs. FDG uptake, and r = 0.65 for FALFF vs. FC).ConclusionThis study indicates that BOLD signals in WM are directly related to variations in metabolic demand and engagement with cortical processing and suggests they should be incorporated into more complete models of brain function.

Anti-BCMA Immuno-NanoPET Radiotracers for Improved Detection of Multiple Myeloma.

Current clinical imaging modalities for the sensitive and specific detection of multiple myeloma (MM) rely on nonspecific imaging contrast agents based on gadolinium chelates for magnetic resonance imaging (MRI) or for 18 F-FDG-directed and combined positron emission tomography (PET) and computed tomography (CT) scans. These tracers are not, however, able to detect minute plasma cell populations in the tumor niche, leading to false negative results. Here, a novel PET-based anti-BCMA nanoplatform labeled with 64 Cu is developed to improve the monitoring of these cells in both the spine and femur and to compare its sensitivity and specificity to more conventional immunoPET (64 Cu labeled anti-BCMA antibody) and passively targeted PET radiotracers (64 CuCl2 and 18 F-FDG). This proof-of-concept preclinical study confirmed that by conjugating up to four times more radioisotopes per antibody with the immuno-nanoPET platform, an improvement in the sensitivity and in the specificity of PET to detect tumor cells in an orthotopic model of MM is observed when compared to the traditional immunoPET approach. It is anticipated that when combined with tumor biopsy, this immuno-nanoPET platform may improve the management of patients with MM.

COVID-19 pneumonia: A review of typical radiological characteristics.

Coronavirus disease 2019 (COVID-19) was first discovered after unusual cases of severe pneumonia emerged by the end of 2019 in Wuhan (China) and was declared a global public health emergency by the World Health Organization in January 2020. The new pathogen responsible for the infection, genetically similar to the beta-coronavirus family, is known as severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), and the current gold standard diagnostic tool for its detection in respiratory samples is the reverse transcription-polymerase chain reaction test. Imaging findings on COVID-19 have been widely described in studies published throughout last year, 2020. In general, ground-glass opacities and consolidations, with a bilateral and peripheral distribution, are the most typical patterns found in COVID-19 pneumonia. Even though much of the literature focuses on chest computed tomography (CT) and X-ray imaging and their findings, other imaging modalities have also been useful in the assessment of COVID-19 patients. Lung ultrasonography is an emerging technique with a high sensitivity, and thus useful in the initial evaluation of SARS-CoV-2 infection. In addition, combined positron emission tomography-CT enables the identification of affected areas and follow-up treatment responses. This review intends to clarify the role of the imaging modalities available and identify the most common radiological manifestations of COVID-19.

Fuzzy FMEA for Biology-Guided Radiotherapy (BgRT)

<h3>Purpose/Objective(s)</h3> Biology-guided Radiotherapy (BgRT) is a new external beam radiotherapy delivery modality combining positron emission tomography-computed tomography (PET-CT) with a linear accelerator. Our research group has previously introduced the BgRT specific prospective process map for developing an initial clinical workflow and has performed the risk analysis for the BgRT process that will bring in a new treatment paradigm. However, due to a lack of experience and historical data, assigning an accurate value of each risk factor in traditional FMEA leads to difficulties for evaluators. Also, there are certain sub-processes where the differences in weights of risk factors needs to be considered. Therefore, in this study, we introduced the fuzzy FMEA to perform a comprehensive analysis of failure modes (FMs) of BgRT and overcome weaknesses of conventional FMEA. <h3>Materials/Methods</h3> Five sub-processes unique to BgRT out of a total of 15 sub-processes were selected and relevant 84 FMs were identified. The evaluators used the fuzzy linguistic variables (very low, low, medium, high, and very high) to evaluate the importance of risk factors for assigning weights as well as the evaluation of each risk factor (occurrence, severity, and detectability) of each failure mode. Then, the fuzzy measure was used to calculate the weights of risk factors and the fuzzy integral method was used to fuse every value of risk factor of FMs to obtain the final fuzzy risk priority number value. <h3>Results</h3> Top 3 FMs are the machine down/emergency during beam delivery, failure to meet activity before PET pre-scan, and failure/delay of tracer delivery from a local vendor. The mitigation plans are discussed by team members including complete guidelines for the emergencies on the treatment machine, maintenance program of PET tracers by dedicated staffs, and staff training program for the BgRT procedure. Strong cooperation with a local PET tracer vendor and timely patient scheduling to allow multiple PET images at the treatment machine were also included in mitigation plans. <h3>Conclusion</h3> The proposed fuzzy FMEA presents a more reasonable and effective method for assessing potential failures allowing fuzzy linguistic variables terms that are easier to use than numerical assignments to evaluate the FMs, especially with the new prototype machine for BgRT. The results have been shared with team members, and mitigation plans will be implemented.

Detection and Characterization of Thrombosis in Humans Using Fibrin-Targeted Positron Emission Tomography and Magnetic Resonance

ObjectivesThe authors present a novel technique to detect and characterize LAA thrombus in humans using combined positron emission tomography (PET)/cardiac magnetic resonance (CMR) of a fibrin-binding radiotracer, [64Cu]FBP8. BackgroundThe detection of thrombus in the left atrial appendage (LAA) is vital in the prevention of stroke and is currently performed using transesophageal echocardiography (TEE). MethodsThe metabolism and pharmacokinetics of [64Cu]FBP8 were studied in 8 healthy volunteers. Patients with atrial fibrillation and recent TEEs of the LAA (positive n = 12, negative n = 12) were injected with [64Cu]FBP8 and imaged with PET/CMR, including mapping the longitudinal magnetic relaxation time (T1) in the LAA. Results[64Cu]FBP8 was stable to metabolism and was rapidly eliminated. The maximum standardized uptake value (SUVMax) in the LAA was significantly higher in the TEE-positive than TEE-negative subjects (median of 4.0 [interquartile range (IQR): 3.0-6.0] vs 2.3 [IQR: 2.1-2.5]; P < 0.001), with an area under the receiver-operating characteristic curve of 0.97. An SUVMax threshold of 2.6 provided a sensitivity of 100% and specificity of 84%. The minimum T1 (T1Min) in the LAA was 970 ms (IQR: 780-1,080 ms) vs 1,380 ms (IQR: 1,120-1,620 ms) (TEE positive vs TEE negative; P < 0.05), with some overlap between the groups. Logistic regression using SUVMax and T1Min allowed all TEE-positive and TEE-negative subjects to be classified with 100% accuracy. ConclusionsPET/CMR of [64Cu]FBP8 is able to detect acute as well as older platelet-poor thrombi with excellent accuracy. Furthermore, the integrated PET/CMR approach provides useful information on the biological properties of thrombus such as fibrin and methemoglobin content. (Imaging of LAA Thrombosis; NCT03830320)

Role of pet/ct in detection of tumor of unknown origin

Abstract Purpose To evaluate the role of combined positron emission tomography and computed tomography (PET/CT) imaging in the detection of tumors of unknown origin. Methods This study included 20 cases presented with pathologically proved metastases of unknown primary or with clinic-radiological suspicion of metastases with unknown primary. Results The number of patients with true positive primary tumor sites was 14 (70%), 2 patients with false-positive results (10%), 2 patients with true negative results (10%) and 2 patients with false-negative results (10%). A sensitivity of 87.5% was achieved, with a specificity of 50% and a total accuracy of 80%. The Positive predictive value was 87.5%%, while the negative predictive value was 50%. The detection rate of the origin of the primary tumor was 70%. Conclusion whole-body FDG-PET/CT has to be considered a useful tool in evaluating metastases from UPT, allowing identification of primary tumors and modifying the stage of the disease and affect the management.

Postmortem diagnosis of pulmonary tumor thrombotic microangiopathy with rapid exacerbation in a patient with gastric cancer: a case report

BackgroundPulmonary tumor thrombotic microangiopathy (PTTM) is a condition that involves the development of pulmonary hypertension due to the presence of microscopic tumor emboli of the peripheral pulmonary arteries. Here, we report a case of rapidly exacerbating PTTM associated with gastric cancer that was identified postmortem through pathological autopsy.Case presentationA 52-year-old Asian woman who experienced anterior chest pain while coughing visited the orthopedic department of the Gifu University Hospital. She was diagnosed as having multiple osteolytic bone metastases throughout her body and was subsequently scheduled to undergo combined positron emission tomography and computed tomography (CT) to search for a primary lesion. However, 4 days after her visit to the orthopedic department, she was unable to stand up and thus visited the emergency department. At the time of admission, physical examination results revealed that she had a percutaneous oxygen saturation level of 90% (on room air) and cyanosis and that she was in a state of hemodynamic shock. Laboratory test results revealed elevated levels of fibrin degradation products and D-dimer in her blood. Chest CT results were normal. She was admitted to the hospital’s general ward for follow-up but soon entered a gradually worsening state of shock and respiratory failure. Electrocardiography revealed findings associated with right heart strain; however, contrast-enhanced CT did not reveal the presence of pulmonary embolism. She was admitted to the intensive care unit and was treated for pulmonary hypertension; however, 45 h after her arrival at the hospital, she died of respiratory failure. A pathological autopsy revealed the presence of gastric cancer, tumor microemboli, and fibrous intimal thickening of the peripheral arteries of both lungs; thus, a diagnosis of PTTM was made.ConclusionsIn patients with carcinoma of unknown primary site and pulmonary hypertension with pulmonary embolism ruled out by CT, emergency physicians and intensivists must consider the possibility of PTTM, which represents an oncologic emergency, and initiate chemotherapy administration as soon as possible.

Correlation of &lt;sup&gt;11&lt;/sup&gt;C-Methionine Combined Positron Emission and Computed Tomography and Ki-67 Proliferation Index in Pretreatment Assessment of Cerebral Gliomas

The purpose of the study was to explore the correlation between 11С-methionine (Met) uptake measured by combined positron emission and computed tomography (PET/CT) in newly diagnosed cerebral gliomas and tumor proliferative activity as measured by Ki-67 labeling index (Ki-67 LI).The results of PET/CT with 11С-methionine (PET-Met) of 236 adult patients with pretreated glial brain tumors were included in retrospective analysis. The final diagnosis of glioma according to WHO classification of CNS tumors (2007) was based on both histology and immunohistochemistry using Ki-67 antibodies. On PET-Met tumor-to normal brain uptake ratio (TBR) was calculated by dividing maximum Met uptake in the tumor (hot spot 10 mm in diameter) to activity concentration in the contralateral cortex. The Spearmen rank correlation test was used to analyze the relationships between TBR and Ki-67 LI.PET-Met analysis showed that TBR increases with an increase in the aggressiveness of the glial tumor. The differences of TBR values between gliomas grade II vs III and grade III vs IV were significant (p &lt; 0,001). Among grades II-III gliomas Met uptake was significantly higher in oligodendroglial and mixed gliomas than in astrocytomas (p &lt; 0,001), but the differences did not depend on Ki-67 LI.Correlation analysis demonstrated significant correlation between Ki-67 LI and TBR values (r = 0,49, p &lt; 0,05, Spearman rank test). With analyzing glioma subgroups TBR values correlated with Ki-67 LI in diffuse astrocytomas (r = 0,52, p &lt; 0,05), oligodendrogliomas (r = 0,40, p &lt; 0,05), oligoastrocytomas (r = 0,47, p &lt; 0,05) and in high-grade gliomas (r = 0,45, p &lt; 0,05) but not in low-grade gliomas. Comparison between TBR value and Ki-67 LI in each glioma showed a lack of coincidence in 22 % of cases (high Met uptake but low Ki-67 LI and vice versa). The main reasons for such discrepancies were tumor molecular biology or incorrect biopsy target.Met uptake in diffuse gliomas correlates with proliferative activity which justifies the use of PET-Met for glioma grading. In case of mismatch between two biomarkers one should rely on the indicator that implies a higher aggressiveness of the glioma.

Determining the extent of tumor resection at surgical planning with 18F-fluciclovine PET/CT in patients with suspected glioma: multicenter phase III trials.

Glioma is the most common type of central nervous system tumor reported worldwide. Current imaging technologies have limitations in the diagnosis and assessment of glioma. The present study aimed to confirm the diagnostic efficacy and safety of anti-1-amino-3-[18F]fluorocyclobutane carboxylic acid (18F-fluciclovine; anti-[18F]FACBC) as a radiotracer for patients undergoing combined positron emission tomography and computed tomography (PET/CT) for suspected glioma. Combined data from two multicenter, open-label phase III clinical trials were evaluated for this study. The two trials enrolled patients with suspected high- or low-grade glioma on the basis of clinical symptoms, clinical course, and magnetic resonance imaging findings, and who were scheduled for tumor resection surgery. Patients fasted for ≥ 4h and received 2mL of 18F-fluciclovine (radioactivity dose 78.3-297.0MBq), followed by a 10-min PET scan 10-50min after injection. The primary efficacy endpoint was the positive predictive value (PPV) of the gadolinium contrast-enhanced T1-weighted image negative [Gd (-)] and 18F-fluciclovine PET-positive [PET ( +)] area of the scans, using the histopathological diagnosis of the tissue sampled from that area as the standard of truth. All adverse events reported during the study were recorded for safety analysis. A total of 45 patients aged 23-89years underwent 18F-fluciclovine PET; 31/45 patients (68.9%) were male, and 30/45 patients (66.7%) were suspected to have high-grade glioma. The PPV of 18F-fluciclovine PET in the Gd (-) PET ( +) area was 88.0% (22/25 areas, 95% confidence interval: 70.0-95.8). The extent of planned tumor resection was modified in 47.2% (17/36 cases) after 18F-fluciclovine PET scan, with an extension of area in 30.6% (11/36 cases) and reduction in 16.7% (6/36 cases). Furthermore, tissue samples collected from PET ( +) areas tended to have a higher malignancy grade compared with those from PET (-) areas. Overall, 18F-fluciclovine was well tolerated. 18F-fluciclovine PET/CT is useful for determining the extent of tumor resection at surgical planning, and may serve as a safe and effective diagnostic tool for patients with suspected glioma. These trials were registered in the Japan Pharmaceutical Information Center Clinical Trials Information (JapicCTI-152986, JapicCTI-152985).

The use of atezolizumab in combination with chemotherapy in first-line of metastatic small cell lung cancer. Case report

Background. Lung cancer (LC) occupies a leading position among malignant tumors in the world, it accounts for 11.4% of the total malignant neoplasms. In 2020, there were 2 206 771 new cases of LC and 1 796 144 deaths worldwide. Among the histological variants, small cell LC (SCLC) has the most unfavorable outcomes. This variant is considered highly sensitive to chemotherapy. Despite some successes in the treatment of this disease, the results of treatment remain problematical. In recent years, the use of immune checkpoint inhibitors has provided significant control of the course of the disease.&#x0D; Aim. To show the efficacy of atezolizumab in combination with chemotherapy in patients with metastatic SCLC.&#x0D; Materials and methods. A 76-year-old patient with left lung cancer, IVA T4N3M1b, the right supraclavicular lymph node metastases, exudative pleuritis of the left lung was under observation. The histological investigation showed SCLC. Brain metastases were not detected. ECOG 0.&#x0D; Results. The patient was treated using atezolizumab 1200 mg in combination with carboplatin 5 AUC and etoposide 100 mg/m2 on days 1, 2, 3 for four cycles, followed by a maintenance therapy regimen with atezolizumab 1200 mg every 21 days. The patient received 21 injections during 14 months. The assessment of treatment effect was evaluated using combined 18F-fluorodeoxyglucose positron emission and X-ray computed tomography. As a result of the treatment, after 7 months, a complete clinical and morpho-metabolic regression of the tumor was reached, which persisted throughout the period of the treatment. Among the adverse events were detected grade 2 anemia and first-stage sensory neuropathy. No immune-related adverse events were observed.&#x0D; Conclusion. The addition of atezolizumab to etoposide + carboplatin as the first-line therapy for extensive-stage SCLC provides the long-term overall and disease-free survival with achieving the satisfactory quality of life in patients and acceptable drug tolerance.

Dose predictions for [177Lu]Lu-DOTA-panitumumab F(ab\u2032)2 in NRG mice with HNSCC patient-derived tumour xenografts based on [64Cu]Cu-DOTA-panitumumab F(ab\u2032)2 \u2013 implications for a PET theranostic strategy

BackgroundEpidermal growth factor receptors (EGFR) are overexpressed on many head and neck squamous cell carcinoma (HNSCC). Radioimmunotherapy (RIT) with F(ab')2 of the anti-EGFR monoclonal antibody panitumumab labeled with the β-particle emitter, 177Lu may be a promising treatment for HNSCC. Our aim was to assess the feasibility of a theranostic strategy that combines positron emission tomography (PET) with [64Cu]Cu-DOTA-panitumumab F(ab')2 to image HNSCC and predict the radiation equivalent doses to the tumour and normal organs from RIT with [177Lu]Lu-DOTA-panitumumab F(ab')2.ResultsPanitumumab F(ab')2 were conjugated to DOTA and complexed to 64Cu or 177Lu in high radiochemical purity (95.6 ± 2.1% and 96.7 ± 3.5%, respectively) and exhibited high affinity EGFR binding (Kd = 2.9 ± 0.7 × 10− 9 mol/L). Biodistribution (BOD) studies at 6, 24 or 48 h post-injection (p.i.) of [64Cu]Cu-DOTA-panitumumab F(ab')2 (5.5–14.0 MBq; 50 μg) or [177Lu]Lu-DOTA-panitumumab F(ab')2 (6.5 MBq; 50 μg) in NRG mice with s.c. HNSCC patient-derived xenografts (PDX) overall showed no significant differences in tumour uptake but modest differences in normal organ uptake were noted at certain time points. Tumours were imaged by microPET/CT with [64Cu]Cu-DOTA-panitumumab F(ab')2 or microSPECT/CT with [177Lu]Lu-DOTA-panitumumab F(ab')2 but not with irrelevant [177Lu]Lu-DOTA-trastuzumab F(ab')2. Tumour uptake at 24 h p.i. of [64Cu]Cu-DOTA-panitumumab F(ab')2 [14.9 ± 1.1% injected dose/gram (%ID/g) and [177Lu]Lu-DOTA-panitumumab F(ab')2 (18.0 ± 0.4%ID/g) were significantly higher (P < 0.05) than [177Lu]Lu-DOTA-trastuzumab F(ab')2 (2.6 ± 0.5%ID/g), demonstrating EGFR-mediated tumour uptake. There were no significant differences in the radiation equivalent doses in the tumour and most normal organs estimated for [177Lu]Lu-DOTA-panitumumab F(ab')2 based on the BOD of [64Cu]Cu-DOTA-panitumumab F(ab')2 compared to those estimated directly from the BOD of [177Lu]Lu-DOTA-panitumumab F(ab')2 except for the liver and whole body which were modestly underestimated by [64Cu]Cu-DOTA-panitumumab F(ab')2. Region-of-interest (ROI) analysis of microPET/CT images provided dose estimates for the tumour and liver that were not significantly different for the two radioimmunoconjugates. Human doses from administration of [177Lu]Lu-DOTA-panitumumab F(ab')2 predicted that a 2 cm diameter HNSCC tumour in a patient would receive 1.1–1.5 mSv/MBq and the whole body dose would be 0.15–0.22 mSv/MBq.ConclusionA PET theranostic strategy combining [64Cu]Cu-DOTA-panitumumab F(ab')2 to image HNSCC tumours and predict the equivalent radiation doses in the tumour and normal organs from RIT with [177Lu]Lu-DOTA-panitumumab F(ab')2 is feasible. RIT with [177Lu]Lu-DOTA-panitumumab F(ab')2 may be a promising approach to treatment of HNSCC due to frequent overexpression of EGFR.

Processing PET/CT Medicine Images and Determining the Object

Today, as a result of the developments in medical imaging systems, combined Positron Emission Tomography and Computed Tomography (PET/CT) images are used as effective imaging tools in cancer diagnosis and treatment. The study aims to display the tumor in 3D using PET/CT images and to determine the change in tumor size over time. For rapid detection of tumor tissues from numerous PET/CT images is developed software (in Phyton). With the software, tomography images taken at 3 different times 30.05.2017, 23.10.2017 and 08.02.2019 of a patient with hypopharynx cancer are evaluated. The image and real object coordinates of the cancerous region with a radioactive substance in the images are calculated. For 3 different times, variables related to changes in the tumor size of the patient are evaluated in Matlab software and 3D imaging and volume calculations are made. Thus, the temporal variation of the shape, location, and dimensions of the tumor is determined, and whether the patient's response to treatment is positive is observed with image processing and evaluation techniques. Keywords: Medical İmage Processing, PET/CT imaging, Segmentation, Thresholding, Volume Rendering, Classification. DOI: 10.7176/JSTR/7-07-04

68Ga-DOTATOC-PET/MRI-A Secure One-Stop Shop Imaging Tool for Robotic Radiosurgery Treatment Planning in Patients with Optic Nerve Sheath Meningioma.

Simple SummaryThrough combined information about spatial spread in magnetic resonance imaging (MRI) and positron emission tomography (PET), gallium-68-labeled (DOTA0-Phe1-Tyr3) octreotide (Ga68-DOTATOC) PET/MRI before radiosurgery allows safe treatment planning for optic nerve sheath meningiomas (ONSM). Moreover, because of specific receptor stocking, diagnostic accuracy is improved without the need for biopsy. Thus, Ga68-DOTATOC-PET/MRI can be considered a safe “one-stop shop” image tool prior to radiosurgery for ONSM.Optic nerve sheath meningiomas (ONSM) are rare but can lead to irreversible blindness. Hybrid imaging may enhance tumor delineation and diagnostic accuracy via receptor binding. However, relevant clinical data for ONSM are lacking. We evaluated the feasibility of receptor-based hybrid imaging prior to robotic radiosurgery (RRS). We retrospectively analyzed all of our institution’s patients with suspected ONSM who underwent combined positron emission tomography and magnetic resonance imaging (PET/MRI) with gallium-68-labeled (DOTA0-Phe1-Tyr3) octreotide (Ga68-DOTATOC) before RRS between 2018 and 2019. Eight patients with ten suspected ONSM (female = 7; median age, 51.2 years; IQR, 43.0–66.0) were included. Nine out of ten ONSM were deemed PET-positive with a median standard uptake value (SUV) max of 5.6 (IQR, 2.6–7.8). For all nine ONSM that presented 68Ga-DOTATOC uptake, hybrid PET/MRI was used for target volume contouring prior to RSS. At a median follow-up of 11.7 months (IQR, 9.4–16.4), tumor control was achieved in all patients. Radiosurgery resulted in the improvement of visual acuity in two of eight patients, whereas six showed stable vision. Ga68-DOTATOC-PET/MRI can be used for target volume contouring prior to RRS for ONSM as it enables safe treatment planning and improves diagnostic accuracy.

Dosimetry and optimal scan time of [18F]SiTATE-PET/CT in patients with neuroendocrine tumours

PurposeRadiolabelled somatostatin analogues targeting somatostatin receptors (SSR) are well established for combined positron emission tomography/computer tomography (PET/CT) imaging of neuroendocrine tumours (NET). [18F]SiTATE has recently been introduced showing high image quality, promising clinical performance and improved logistics compared to the clinical reference standard 68Ga-DOTA-TOC. Here we present the first dosimetry and optimal scan time analysis.MethodsEight NET patients received a [18F]SiTATE-PET/CT (250 ± 66 MBq) with repeated emission scans (10, 30, 60, 120, 180 min after injection). Biodistribution in normal organs and SSR-positive tumour uptake were assessed. Dosimetry estimates for risk organs were determined using a combined linear-monoexponential model, and by applying 18F S-values and reference target masses for the ICRP89 adult male or female (OLINDA 2.0). Tumour-to-background ratios were compared quantitatively and visually between different scan times.ResultsAfter 1 h, normal organs showed similar tracer uptake with only negligible changes until 3 h post-injection. In contrast, tracer uptake by tumours increased progressively for almost all types of metastases, thus increasing tumour-to-background ratios over time. Dosimetry resulted in a total effective dose of 0.015 ± 0.004 mSv/MBq. Visual evaluation revealed no clinically relevant discrepancies between later scan times, but image quality was rated highest in 60 and 120 min images.Conclusion[18F]SiTATE-PET/CT in NET shows overall high tumour-to-background ratios from 60 to 180 min after injection and an effective dose comparable to 68Ga-labelled alternatives. For clinical use of [18F]SiTATE, the best compromise between image quality and tumour-to-background contrast is reached at 120 min, followed by 60 min after injection.

Atherosclerosis inflammation and burden in young adult smokers and vapers measured by PET/MR

Background and aimsElectronic cigarette (EC) use is popular among youth, touted as a safer alternative to smoking and promoted as a tool to aid in smoking cessation. EC cardiovascular safety however is not well established. The aim of this study was to examine cardiovascular consequences of EC use by evaluating their effect on the entire atherosclerotic cascade in young adults using noninvasive combined positron emission tomography (PET)/magnetic resonance imaging (MR) and comparing EC use with age matched smokers of traditional cigarettes and nonsmoking controls. MethodsCarotid PET/MR was applied to look at vascular inflammation (18-fluorodeoxyglucose (FDG)-PET) and plaque burden (multi-contrast MR of vessel wall) from 60 18-30 year-old subjects (20 electronic cigarette users, 20 traditional smokers and 20 nonsmokers). ResultsGroups were reasonably well balanced in terms of age, gender, demographics, cardiovascular risk and most biomarkers. There were no differences in vascular inflammation as measured by 18-FDG-PET target to background ratios (TBR) between EC users, traditional cigarette smokers and nonsmokers. However, measures of carotid plaque burden − wall area, normalized wall index, and wall thickness − measured from MR were significantly higher in both traditional smokers and EC users than in nonsmokers. ConclusionsYoung adult EC users, smokers and nonsmokers in our study did not exhibit vascular inflammation as defined by 18-F-FDG-PET TBR max, but smokers and EC users had significantly more carotid plaque burden compared to matched nonsmokers. Results could indicate that vaping does not cause an increase in vascular inflammation as measured by FDG-PET.

Ревматическая полимиалгия в клинических рекомендациях 2018–2020 гг. Часть II: диагностика васкулита

Совершенствование диагностики ревматических болезней пожилых людей и заболеваний аорты— актуальные задачи медицины. В патогенезе аневризм, расслоений, разрывов аорты важна роль воспаления и структурных изменений ее стенки, которые выявляют с помощью визуализирующих методов. Ведению ревматической полимиалгии, гигантоклеточного артериита, аневризм аорты посвящен ряд международных рекомендаций. С аортитом сопряжено до 40% случаев ревматической полимиалгии. Клиническое подозрение на него основано на выявлении асимметрии артериального давления и пульса, шума аортальной регургитации, сосудистых шумов, персистенции ревматической полимиалгии, воспалительной боли в спине, области таза и нижних конечностях. В 2020 году именно позитронно-эмиссионная томография/компьютерная томография рекомендована Итальянским обществом ревматологов для диагностики васкулита при ревматической полимиалгии во вторичном звене и Европейской федерацией головной боли для диагностики крупнососудистого гигантоклеточного артериита в неврологической практике. Приведен обзор рекомендаций Европейской ассоциации ядерной медицины, Общества ядерной медицины и молекулярной визуализации и Американского общества ядерной кардиологии по применению позитронно-эмиссионной томографии с фтордеоксиглюкозой в сочетании с компьютерной томографией (ангиографией) при васкулитах крупных сосудов и ревматической полимиалгии (2018). Они сопоставлены с клиническими руководствами, другими рекомендациями обществ ядерной медицины и новыми научными данными. Описана процедура исследования и подготовка к нему. Рассмотрены критерии оценки васкулита, предложенные для клинической практики и для клинических исследований, а также факторы, влияющие на результаты теста и их интерпретацию (атеросклероз, диабет, возраст, индекс массы тела, уровни гликемии и маркеров острой фазы). В рекомендациях обоснована польза применения позитронно-эмиссионной томографии и ее сочетания с компьютерной томографией для выявления экстракраниального васкулита и ценность компьютерной томографии-ангиографии на разных стадиях болезни. Требует усиления доказательная база стандарта времени экспозиции фтордеоксиглюкозы и пользы сочетания позитронной эмиссионной томографии с компьютерной томографией-ангиографией, в том числе для выявления рецидивов васкулита и мониторинга терапии. Необходим консенсус по раннему выполнению исследования, стандартизация оценок его результатов, обеспечение реимбурсации, внедрение новых методик визуализации сосудов черепа. В перспективе доказательный подход к ведению васкулита дополнит терагностика.