THE DIAGNOSTIC ACCURACY OF A COMBINATION OF PREOPERATIVE 68-Ga PSMA PET/CT AND MULTIPARAMETRIC MRI IN LOCALIZED PROSTATE CANCER.

INTRODUCTION: Prostate cancer (PCa) is a common and leading course of cancer-related death in men. Although there are studies on multiparametric magnetic resonance imaging (MpMRI) with good diagnostic results in detecting clinically significant prostate cancer, new methods have been investigated due to the low positive predictive values. In this context, Prostate Specific Membrane Antigen Positron Emission Tomography (PSMA PET) emerges as an alternative imaging method to MpMRI. This study aims to compare 68Ga PSMA I&T-PET/CT and MpMRI in determining tumor location. METHODS: Preoperative MpMRI and 68Ga PSMA I&T-PET/CT scans and pathology specimens of who underwent radical prostatectomy for PCa at our clinic between 2018-2021 were retrospectively evaluated. PSMA I&T-PET/CT, MpMRI, combined imaging were compared for tumor localization according to histopathological data. RESULTS: In terms of tumor localization, MpMRI demonstrated overall accuracy rates 75.9% (p kappa (κ) 0.0001* (0.525)). 68Ga PSMA I&T-PET/CT showed 71.5% (p κ 0.0001* (0.438)). For the combined imaging approach overall accuracy rate were calculated as 79.2% (p κ 0.0001* (0.576)). Additionally, high diagnostic accuracy was achieved for the combined imaging approach, particularly in the intermediate ISUP group. Moreover, SUVmax was calculated as 6.37. CONCLUSION: The combined use of 68Ga PSMA I&T-PET/CT and MpMRI has high diagnostic rates. However, the high cost is a significant disadvantage that limits their routine combined use.

Comparison of three different methods in [68 Ga]Ga-PSMA11 radiolabeling.

In this study, quality control parameters such as radiochemical yield, radiochemical purity, and in vitro stability of gallium (68 Ga)-prostate-specific membrane antigen-11 ([68 Ga]Ga-PSMA11) radiopharmaceutical obtained in a research laboratory with three different synthesis algorithms were evaluated and compared. Gallium (68 Ga) chloride precursor to be used in labeling in all three methods was obtained by using ITG brand 68 Ge/68 Ga generator. The first method for the [68 Ga]Ga-PSMA11 radiopharmaceutical was performed with the automated synthesis module, which is widely used in clinical practice. Its radiochemical yield, quality assurance, and stability met expectations. Radiolabeling success, suitability of quality control parameters, and in vitro stability of [68 Ga]Ga-PSMA11 radiopharmaceutical performed with ANMI kit were examined. The final product showed success in 68 Ga-complexation kinetics. All quality control criteria performed met the expectation for clinical applications. Direct cold labeling of PSMA11 ligand with sodium bicarbonate buffer was examined. Results were similar to the ANMI kit. Considering that all three methods are successful in radiochemical labeling, labeling with NaHCO3 buffer shows the labeling preference when we choose the cheap, practical, and easy labeling option.

Comparison of 68Ga-PSMA-I/T PET-CT and Multiparametric MRI for Locoregional Staging of Prostate Cancer Patients: A Pilot Study.

BACKGROUND/AIM: The objective of this work was to assess the value of 68Ga-DOTAGA-(3-iodo-y)fk(Sub-KuE) positron emission tomography (68Ga-PSMA-I/T PET-CT) and multiparametric magnetic resonance imaging (mp-MRI) for preoperative staging in prostate cancer (PCa) patients who underwent radical prostatectomy (RP) by validating with postoperative histopathology data. MATERIALS AND METHODS: We prospectively investigated 30 consecutive PCa patients who had both mp-MRI and 68Ga-PSMA-I/T PET-CT before laparoscopic RP. The seminal vesicle invasion (SVI), lymph node metastasis (LNM), bladder neck invasion (BNI), and extracapsular extension (ECE) were investigated separately. The diagnostic performances of mp-MRI and 68Ga-PSMA-I/T PET-CT were assessed using histopathological results. RESULTS: Both mp-MRI and 68Ga-PSMA-I/T PET-CT were not statistically significant in the evaluation of SVI, BNI, and ECE preoperatively but had statistically significant results in the assessment of LNM. mp-MRI had higher overall sensitivity for ECE, overall specificity for SVI, ECE, and BNI, and positive predictive value for ECE, SVI, BNI. 68Ga-PSMA-I/T PET-CT had higher overall sensitivity for BNI, and negative predictive value for BNI and LNM. CONCLUSION: mp-MRI has superior specificity, sensitivity, and accuracy for assessing ECE and SVI. Both imaging modalities had similar specificity, sensitivity, and accuracy for determining BNI. However, both imaging modalities had low diagnostic accuracy for LNM on histopathology.

68Ga-citrate positron emission tomography/computed tomography findings in an experimental model of acute appendicitis in rabbits.

OBJECTIVE: Acute appendicitis (AA) is a common urgent surgical situation of the gastrointestinal tract. Gallium-68 (68Ga)-citrate has been recently investigated as a radiopharmaceutical for infection and inflammation imaging. Aim of the study was to determine the effectiveness of 68Ga-citrate positron emission tomography/computed tomography (PET/CT) imaging in rabbits with experimentally induced AA. MATERIALS AND METHODS: In the AA group (n=6), the appendices of the rabbits were surgically ligated. The sham group (n=6) was used as control. Gallium-68-citrate was synthesized. All rabbits were imaged using 68Ga-citrate PET/CT at 36th following the establishment of experimental models, and at 36th h, all rabbits were appendectomised. Appendices were examined histopathologically. Blood samples were drawn from all rabbits at the beginning and end of the experimental process. Interleukin-6 (IL-6) and procalcitonin (Pct) levels were measured. Acute appendicitis was confirmed histopathologically and biochemically. RESULTS: Gallium-68-citrate PET/CT showed acute appendicitis in all rabbits. The sensitivity, specificity and accuracy of 68Ga-citrate PET/CT in AA were 100%, 83.3% and 91.7%, respectively. CONCLUSION: Acute appendicitis is accurately imaged in an experimental rabbit model by using 68Ga-citrate with PET/CT.

Hemorheological dysfunction in cardiac syndrome X.

BACKGROUND: Cardiac syndrome X (CSX) is often described as angina or angina-like chest pain with a normal coronary arteriogram, yet the underlying pathophysiological mechanisms have not been fully elucidated. The aim of the current study was to determine alterations in blood rheology (erythrocyte aggregation and deformability, plasma viscosity - PV) in patients with CSX. METHODS: The study comprised 26 CSX patients (55.77 ± 12.33 years) and 37 age- and sex-matched (56.32 ± 11.98 years) healthy controls. Erythrocyte aggregation and deformability were measured by an ektacytometer and PV with a rotational viscometer. RESULTS: Erythrocyte deformability measured at 1.69 and 3.00 Pa was lower in the CSX patients compared to the controls (p = .0001 and .017, respectively). Erythrocyte aggregation index (AI) (72.758 ± 7.65 vs. 66.483 ± 6.63, p = .002) and PV measured at a shear rate of 375 s-1 (1.932 ± 0.225 vs. 1.725 ± 0.331, p = .019) were significantly higher in patients with CSX. When AI, RDW and erythrocyte deformability measured at 1.69 Pa were evaluated together, it was observed that the increase in AI and RDW augments the risk of having CSX (OR: 1.2 and 2.65, respectively), while the rise in deformability decreases this risk (OR = 0.02). CONCLUSIONS: Hemorheological impairments are associated with CSX.

Fatal Pulmonary Embolism Due to Inherited Thrombophilia Factors in a Child With Wolfram Syndrome.

Wolfram syndrome-1 is a rare and severe autosomal recessive neurodegenerative disease characterized by diabetes mellitus (DM), optic atrophy, diabetes insipidus, and deafness. Poorly controlled type 1 DM increases the risk for thrombosis. However, coexistence of DM and hereditary thrombosis factors is rarely observed. Here we present the case of a 13.5-year-old, nonfollowed girl newly diagnosed with poorly controlled Wolfram syndrome on the basis of the results of clinical and laboratory examinations. On the eighth day after diabetic ketoacidosis treatment, pulmonary embolism developed in the subject. Thrombus identified in the right atrium using echocardiography was treated by emergency thrombectomy. Homozygous mutation in the methylenetetrahydrofolate reductase gene C677T, heterozygous factor-V Leiden mutation, and active protein C resistance were identified in the patient. The patient was lost because of a recurring episode of pulmonary embolism on the 86th day of hospitalization. We present this case to highlight the need for investigating hereditary thrombosis risk factors in diabetic patients in whom thromboembolism develops.

Can Pantoprazole be Used for Premedication in Meckel Scintigraphy?

Objectives: Meckel scintigraphy is used to diagnose Meckel's diverticulum. Previously, premedication with ranitidine was the most frequently used method to increase the accuracy of scintigraphy. However, ranitidine can no longer be used because it is banned by the Food and Drug Administration. The aim of this study was to investigate the usability of pantoprazole as a premedication instead of ranitidine in Meckel scintigraphy. Methods: Twelve New Zealand rabbits were used in this experimental study. Rabbits were divided into two groups: pantoprazole and control. Six rabbits were premedicated with pantoprazole for three days. Meckel scintigraphy was performed on all rabbits. Counts were made and compared by drawing regions of interest from the stomach walls. Results: According to the findings of this experimental study, pantoprazole significantly increased Tc-99m-pertechnetate uptake in the stomach of rabbits on both visual and quantitative evaluation. Conclusion: Pantoprazole increases the gastric wall uptake of Tc-99m-pertechnetate in rabbits and is a potential drug for premedication in Meckel scintigraphy.

A New Buffer for Gallium-68 Labeling Suitable for use in Nuclear Medicine; Triethanolamine (TEA).

BACKGROUND: Radiopharmaceuticals labeled with [68Ga] from positron emission tomography (PET) radionuclides are utilized in nuclear medicine for non-invasive in vivo molecular imaging. Buffer solutions for radiolabeling play an important role as choosing the right buffer for the reaction helps to obtain high yield radiopharmaceuticals. Zwitterionic organic buffer 4-(2- hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES), sodium acetate (CH3COONa), sodium bicarbonate (NaHCO3) buffers are widely used for labeling of peptides with [68Ga]Cl3. They can be used for peptide labelings with the acidic [68Ga]Cl3 precursor of triethanolammonium (TEA) buffer. The cost and toxicity of TAE buffer are relatively low. METHOD: For [68Ga]GaPSMA-HBED-CC and [68Ga]GaDOTA-TATE labeling, the effectiveness of TEA buffer without chemical impurities in radiolabeling reactions and QC parameters in successful labeling was investigated. RESULTS: The method used to label [68Ga]Cl3 with PSMA-HBED-CC peptide in the presence of TEA buffer was successful when applied at room temperature. High purity radiosynthesis suitable for clinical use was performed to obtain DOTA-TATE peptide with the addition of 363K temperature and radical scavenger. Quality control tests with R-HPLC have shown that this method is suitable for clinical use. CONCLUSION: We present an alternative procedure for labeling PSMA-HBED-CC and DOTATATE peptides with [68GaCl3] to obtain high radioactive doses of final radiopharmaceutical products used in nuclear medicine clinical applications. We have provided a quality-controlled final product that can be used in clinical diagnostic procedures. With the use of an alternative buffer, these methods could be adapted to semi-automatic or automated modules routinely used in nuclear medicine laboratories to label [68Ga]-based radiopharmaceuticals.

Confirmation of PSMA expression measured on [68Ga]Ga-PSMA PET/CT by immunohistochemistry in prostate adenocarcinoma.

BACKGROUND: Our aim is to determine the accuracy of [68Ga]Ga-PSMA PET/CT in showing PSMA expression in primary prostate cancer and to investigate the relationship between SUVmax and immunohistochemical PSMA expression, Gleason score, and PSA value. MATERIAL AND METHODS: We retrospectively analyzed 66 male patients who were diagnosed with primary prostate adenocarcinoma, underwent pre-treatment [68Ga]Ga-PSMA PET/CT examination for staging, and performed radical prostatectomy between March 2018-August 2020. Immunohistochemical staining was applied to the radical prostatectomy specimens of all patients to detect PSMA expression. The results were evaluated as an immunoreactive score (IRS) and a modified IRS was obtained. Gleason score groups and prostate-specific antigen (PSA) serum values of the patients were obtained from the patient files. RESULTS: The high SUVmax of primary prostate tumors was significantly correlated with a high modified IRS score (score 2; 3), high PSA value, high Gleason score, and metastasis. In correlation analysis, a positive correlation was found between SUVmax and PSA value and modified IRS score (r = 0.69, p = 0.001; r = 0.39, p = 0.001). In addition, there was a statistically significant weak correlation between PSA serum concentration and modified IRS scores (r = 0.267; p = 0.03). In regression analysis, the percentage of positive cells had a statistically significant and increasing effect on SUVmax (p = 0.031; std beta = 0.268; 95% CI = 0.231-4.596). CONCLUSIONS: In prostate adenocarcinoma, SUVmax of the primary tumor in [68Ga]Ga-PSMA PET/CT correlates with immunohistochemical PSMA expression. In addition, high SUVmax is associated with markers of poor prognoses, such as high PSMA expression, PSA value, and Gleason score.

Role of F-18 FDG PET/CT in Predicting Response to Neoadjuvant Chemotherapy in Invasive Ductal Breast Cancer.

Objective: The role of baseline and post-treatment standardized uptake value (SUVmax) values in predicting pathological response in patients with breast cancer after neoadjuvant chemotherapy (NAC). Materials and Methods: Thirty patients with invasive ductal breast cancer were included in this retrospective study. F-18 fluorodeoxyglucose (FDG) positron emission tomography/computerized tomography (PET/CT) examinations were performed before and after NAC. Pretreatment SUVmax (SUVmax I), post-treatment SUVmax (SUVmax II) and ΔSUVmax values of primary breast cancer were obtained. Breast tumor pathology preparations were examined for the evaluation of tumor response according to the Miller and Payne classification. Patients were grouped as responding to treatment (pCR) and unresponsive to treatment (nonpCR). In all analyses, p<0.05 was considered statistically significant. Results: The mean age of the 30 patients included in the study was 51.2±11.98 years. In the study-defined grouping, 13 patients (43.3%) were nonresponders and 17 patients (56.7%) were responders. ΔSUVmax was significantly greater in the responders group compared to the nonresponders group, while SUVmax II was lower (p = 0.001 and p = 0.004, respectively). There was no significant difference between the responders and nonresponders in terms of age, tumor diameter, and SUVmax I values. Multivariate logistic regression analysis showed ΔSUVmax to be the only independent predictive factor for pCR. Conclusion: F-18 FDG PET/CT was an effective method in evaluating the treatment response after NAC in breast cancer, and ΔSUVmax and post-treatment SUVmax can be used to predict the response of the primary tumor to treatment.

Relationships of 18F-FDG uptake by primary tumors with prognostic factors and molecular subtype in ductal breast cancer.

OBJECTIVES: In this study, we aimed to investigate the correlation between SUVmax of primary tumor and prognostic factors/molecular subtype in ductal breast cancer patients. MATERIALS AND METHODS: We retrospectively reviewed 150 female patients with pathologically proven invasive ductal breast cancer from January 2015 to October 2019 who underwent 18F-FDG PET/CT for initial staging. Histopathological prognostic features of the primary tumor (histological grade, hormone receptor status, Ki-67 index, vb.) were obtained from the tru-cut biopsy report. In 18F-FDG PET/CT studies, the maximum standardized uptake value (SUVmax) of the primary breast tumor was calculated and compared with the presence of axillary lymphadenopathy and/or distant metastases, histopathological prognostic factors and molecular subtype. RESULTS: The high SUVmax of primary breast tumors is significantly correlated with the clinicopathological factors: high tumor size, high histologic grade, high Ki-67 index, axillary lymph node positivity and distant metastasis. SUVmax value was significantly higher in patients with basal subtype than patients with Luminal A subtype (8,14 ±â€¯3,71 and 4,64 ±â€¯2,45, p = 0,002). Correlation analysis revealed a low correlation between Ki-67 index and SUVmax (r = 0,276, p = 0,001) and moderate correlation between tumor size and SUVmax (r = 0,470, p = 0,001). In multivariate linear regression analysis, Ki-67 index and tumor size had a statistically significant effect on SUVmax values. As these parameters increase, it is seen that it increases SUVmax values (p = 0,004, Std Beta: 0,228, 95% CI:0,010-0,055 and p = 0,001, Std Beta:0,374, 95% CI:0,55-0,136, respectively). CONCLUSION: High SUVmax value is associated with factors suggesting poor prognosis. Pretreatment 18F-FDG PET/CT can be used as a tool to predict prognosis in breast cancer.

Examination of metallic impurities of 68Ge/68Ga generators used for radioactive labeling of peptides in clinical PET applications.

BACKGROUND/AIM: Especially suitable for PET due to its nuclear physical and radiochemical properties, the positron emitter Gallium-68 (Ga) occurs by electron capture from Germanium-68 (Ge). In such a radionuclide generator, the germanium is bound to an insoluble, inert column matrix and forms a secular radioactive balance with 68Ga obtained in the hour. As a result of the limited radiochemical selectivity of the elution process, the eluate obtained is basically contaminated with the main nuclide traces, so that the eluate becomes a mixture of Ga and Ge radionuclides. Also, the generator eluate contains a number to metal cations that reduce specific radioactivity and can compete with 68Ga. The presence of toxic metal that can be found in the eluate carries the risks of contamination at every step from the production of generators to radiopharmaceutical production. MATERIALS AND METHOD: In our study, by collecting the eluate of the Ge/Ga generators used with different identities in different centers in Turkey, we report comparative analysis of metal contamination in the generator eluate. The eluates of 68Ge/68Ga generators to five different identities were collected. Eluates were analyzed by inductively coupled plasma-mass spectrometry. RESULTS AND CONCLUSION: As a result, each generator contains metallic impurities different from its certificate.

Comparison of Radiochemical and Chemical Impurities in Liquid Wastes of Two Different 68Ge/68Ga Generators used in Nuclear Medicine PET Chemistry

Objectives: Germanium-68/gallium-68 (68Ge/68Ga) generator eluate contains a number of metal cations that can compete with 68GaCl3, reducing specific radioactivity. The first step in peptide labeling with 68GaCl3 is to remove 68Ge and several other metals with a long half-life. In this purification step, the elution residue that is passed through the cartridge is collected in glass waste bottles. Waste management is included in good production practices, and in particular, the activity of long half-life 68Ge (270.95 days) and other toxic metal levels need to be examined. Our objective in this study is to determine the 68Ge activity in liquid waste produced by the generation of 68Ga and heavy metal concentrations from the generator column materials and to assess whether it can be disposed of as normal waste. Methods: Liquid wastes produced by passing the 68Ge/68Ga generator eluate of 2 different identities via PSH+ cartridge have been analyzed with the inductively coupled plasma mass spectrometry device in the advanced technology application and research center of our university. Results: The average of the 68Ge radioactive pollution was estimated to be 0.142 ppm (µg.mL-1) in the liquid waste analysis after passing through the PSH+ cartridge in the pre-elution in the GalluGEN brand generator. While there was no tin (Sn) impurity, it was determined that the average zinc (Zn) was 1.95 ppm (µg.mL-1) and the average aluminum (Al) impurity was 10.95 ppm (µg.mL-1). While no 68Ge radioactive pollution was determined in the iThemba LABS brand generator, the average Sn was 0.098 ppm (µg.mL-1), average Zn 48.6 ppm (µg.mL-1), and average Al impurity 4.135 ppm (µg.mL-1). Conclusion: All 68Ge/68Ga generators produced have their own certificates. Metallic contamination in the postmarking waste of 68Ge/68Ga generators can be different. It would be a safe method to keep these wastes in place until they are dumped into the sewage systems, given their half-lives in terms of long half-life radioactive metallic contamination.

Validation of HPLC method for the determination of chemical andradiochemical purity of a 68Ga-labelled EuK-Sub-kf-(3-iodo-y-) DOTAGA.

The prostate-specific membrane antigen (PSMA) represents an ideal biomarker for molecular imaging. Various PSMA-targeted radioligands are available for prostate cancer imaging. In this study, labeling of PSMA I&T with 68Ga, as well as validation of the radiochemical purity of the synthesis product by reverse phase radio high-performance liquid chromatography (HPLC) method are intended. Since the standard procedure for the quality control (QC) was not available, definition of chemical and radiochemical purity of 68Ga-PSMA I&T was carried out according to the Q2 (R1) ICH guideline. The standard QC tests were analyzed with Scintomics 8100 radio-HPLC system equipped with a radioactivity detector. The method was evaluated in terms of linearity, precision and accuracy, LOQ, robustness parameters, and specificity. To assess the radiochemical and chemical purity of 68Ga-PSMA I&T, the developed method was validated to apply safely to patients. An excellent linearity was found between 1µg/mL and 30 µg/mL, with a limit of detection and limit of quantitation of 0.286 µg/mL and 0.866 µg/mL, respectively for 68Ga-PSMA I&T. The recovery was 96.8 ± 3.8%. The quality control of the final product was performed many times with validated radio-HPLC method and was found to comply with ICH requirements, thus demonstrating the accuracy and robustness of the method for routine clinical practice.

Can 18Fluoro-deoxy-glukose-Positron Emission Tomography/Computed Tomography be a Useful for Decision of Elective Surgery in Thoracic Aortic Aneurysm.

Thoracic aortic aneurysm (TAA) should be treated before the complications with prophylactic surgery. However, important number of ruptures have been occurred below the cut-off size for surgery. In addition, in some cases, who in the cut-off value limit, decision of surgery may sometimes be difficult. 18Fluoro-deoxy-glukose positron emission tomography/computed tomography (18FDG-PET/CT) may useful such situations. We present a case that, TAA in 18FDG-PET/CT in a patient with larynx carcinoma. He had a TAA with near the cut-off value and increased metabolic activity in baseline imaging. After 3 months, SUVmax value increased and elective surgery was performed. We think that aneurysms may be another pathology that 18FDG-PET/CT potentially be useful apart from imaging malignant diseases.

Can PET/CT be used more effectively in pleural effusion evaluation?

PURPOSE: Sometimes, characterization of pleural effusion (PE) can be challenging especially in patients whom invasive procedures/recurrent invasive procedures cannot be performed. The main purpose of the study is to answer this question, Can 18F-FDG-PET/CT contribute to reduction in the number of invasive procedures or patients undergoing to invasive procedures? Results may increase the effectiveness of patient management by facilitating clinical decision-making, especially in patients who cannot undergo invasive/recurrent invasive procedures. METHODS: Sixty-seven patients' 18F-FDG-PET/CT, pleural fluid cytologies (PFCs) and, if any, pleural biopsies were re-assessed. If patient's PFC/biopsy was malignant, effusion was considered as malignant. If two consecutive PFCs were negative in patients without biopsy, effusion was considered as benign. Characterization was based on consensus with baseline/follow-up 18F-FDG-PET/CT and clinical parameters in patients with one negative PFC (n = 6). RESULTS: None of the 18F-FDG-PET/CT parameters could characterize PE alone. However, if PE maximum standardized uptake value (SUVmax) > 1.3 or PE SUVmax/mean standardized uptake value of mediastinal blood pool (MBP SUVmean) > 1.2 was combined with at least one of the following, specificity and positive predictive value (PPV) were 100%, accuracy was around 90%. Diffuse-nodular/nodular pleural thickness, post-obstructive atelectasis, nodule/mass with SUVmax > 2.5 in lung, multiple pulmonary nodules. All 29 patients who had SUVmax > 1.3 together with at least one of the mentioned four parameters diagnosed malignant pleural effusion (MPE). However, sensitivity and negative predictive value (NPV) were still insufficient. CONCLUSION: Patients who have contraindications for invasive diagnostic methods, and meet the aforementioned criteria may be considered as MPE primarily. On the other hand, if PE SUVmax < 1.3 or PE SUVmax/MBP SUVmean < 1.2 with the negativity of the all four parameters mentioned above, it is difficult to say that this can be considered as benign pleural effusion (BPE) according to our results.

Detection of Pulmonary Embolism with Gallium-68 Macroaggregated Albumin Perfusion PET/CT: An Experimental Study in Rabbits.

This study was designed to evaluate the accuracy of detecting pulmonary embolism (PE) using the Technegas SPECT/CT combined with 68Ga PET/CT in a rabbit model. One hour after artificial PE (n = 6) and sham (n = 6) models were created, Technegas SPECT/CT ventilation and 68Ga-MAA PET/CT perfusion scan (V/Q scan) were performed. Ventilation imaging was performed first on all cases. Technegas SPECT/CT and 68Ga-MAA PET/CT images were evaluated by a nuclear medicine physician who recorded the presence, number, and location of PE on a per-lobe basis. The sensitivity, specificity, and accuracy of Technegas SPECT/CT and 68Ga-MAA PET/CT for detecting PE were calculated using a histopathological evaluation as a reference standard. A total of 60 lung lobes were evaluated in 12 rabbits, and PE was detected in 20 lobes in V/Q scans and histopathological analysis. The overall sensitivity, specificity, and accuracy were 100%, 100%, and 100%, respectively, for both the Technegas SPECT/CT and 68Ga-MAA PET/CT V/Q scans. Technegas/68Ga-MAA V/Q scans have good sensitivity, specificity, and accuracy in the detection of PE in this animal model study.

Hemorheology and oxidative stress in patients with differentiated thyroid cancer following I-131 ablation/metastasis treatment.

BACKGROUND: Although radioiodine theraphy (RAIT) is thought to affect blood cells and oxidative stress, hemorheological alterations following dose-dependent RAIT remains unknown. OBJECTIVE: The aim of this study was to determine the effects of RAIT on hemorheological and oxidative stress parameters in patients with differentiated thyroid cancers (DTC). METHODS: Totally 31 DTC patients (mean age 46.32±11.15 years) and 26 healthy controls (mean age 50.50±6.22 years) were included. Venous blood samples were collected from each patient before and after treatment (7th day, 1th month and 6th month). Erythrocyte aggregation-deformability and oxidative stress parameters were determined. p < 0.05 was considered as statistically significant. RESULTS: Erythrocyte deformability of the patients determined at 16.87 and 30 Pascal were significantly lower than healthy individuals. Erythrocyte aggregation index (AI) of the patients was higher, whereas erythrocyte aggregation half-time (t½) was lower compared to control. Erythrocyte deformability values and AI were not significantly different from the pre- and post-radioiodine treatment groups. There was no statistically significant difference between the oxidative stress parameters before and after the treatment. CONCLUSIONS: Patients were in a worse hemorheological condition compared to healthy individuals. After RAIT, RBC deformability and aggregation were not affected and no significant change in oxidative stress parameters was detected.

Diagnosis of Sarcopenia in Head and Neck Computed Tomography: Cervical Muscle Mass as a Strong Indicator of Sarcopenia.

OBJECTIVES: Patients with head and neck cancer (HNC) have a high risk of sarcopenia, which is associated with poor prognosis. Skeletal-muscle area and index at the third lumbar (L3) vertebra level (L3MA and L3MI) are recommended for the detection of sarcopenia. However, L3 level is not included in many imaging protocols and there are no data for optimal levels and cutoffs for the diagnosis of sarcopenia in head and neck computed tomography (HNCT) scans. Our aim was to assess the relationship between cervical paravertebral muscle values and L3MI and to investigate optimal level to diagnose sarcopenia on HNCTs. METHODS: Patients with HNC (n=159) who underwent positron emission tomography-CT for tumor staging were retrospectively analyzed. On CT images, paravertebral and sternocleidomastoid muscle areas at second (C2), third (C3), and fourth (C4) cervical vertebrae levels (C2MA, C3MA, C4MA, SCMA) and L3MA were measured. Cross-sectional areas were normalized for stature (muscle area/height square) and muscle index (C2MI, C3MI, C4MI, SCMI, L3MI) values were obtained. Spearman correlation and linear regression analyses were used for assessing correlations. To calculate the diagnostic performance of SCMI, C2MI, C3MI, and C4MI for the diagnosis of sarcopenia with respect to the cutoffs of L3MI, receiver operating characteristic (ROC) analysis was used. RESULTS: Males had significantly higher muscle areas than females. Although C2MI, C3MI, C4MI, and SCMI values all showed very strong and significant correlation with L3MI (P<0.001). According to the ROC analysis, the best discriminative for sarcopenia was C3MI in males (area under curve [AUC], 0.967) and SCMI in females (AUC, 0.898). CONCLUSION: C2MI, C3MI, C4MI, and SCMI values can be used as alternatives for the diagnosis of sarcopenia in routine HNCT examinations.

Incidental "Urinoma" in 18F-FDG PET/CT Scan

18F-FDG PET/CT scanning was performed for the primary staging of a 47-year-old man with urothelial carcinoma. The patient underwent biopsy by ureteroscopy 15 days ago and the PET images revealed 18F-FDG accumulation in the right retroperitenal region, compatible with an "urinoma".