Third-order nonlinear optical properties of highly electron deficient, nonplanar push-pull porphyrins: β-nitro-hexa-substituted porphyrins bearing bromo, phenyl, and phenylethynyl groups

β-Heptasubstituted porphyrins [MTPP(NO2)X6; M = 2H, NiII, CuII, and ZnII; X = Br, Ph, and PE] were synthesized and their third-order nonlinear optical (NLO) properties explored using the single-beam Z-scan technique with femtosecond, MHz pulses in the visible range. The three-photon absorption (γ), third-order nonlinear optical susceptibility (χ3), three-photon absorption cross-section (σ3), and nonlinear refractive index (n2) have been determined from theoretical fits with experimental results. The sign and magnitude of the nonlinear refractive index (n2) have been obtained from the closed-aperture experiment while the three-photon absorption coefficient and three-photon absorption cross-section were determined from the open-aperture experiment. The magnitudes of the 3PA and σ3 extended in the range of (2.7-3.4) × 10-23 cm3 W-2 and (5.5-7.0) × 10-78 cm6 s2, respectively. The higher magnitude of the NLO coefficients ensures their utility in optical and photonic applications.

68Ga-DOTA.SA.FAPi as a Versatile Diagnostic Probe for Various Epithelial Malignancies: A Head-to-Head Comparison with 18F-FDG

RATIONALE AND OBJECTIVES

Fibroblast Activation Protein (FAP) expressing cancer-associated fibroblasts has been a major breakthrough causing a paradigm shift in targeted theranostics focusing on the tumor microenvironment. In this study, a squaric acid derivative DOTA.SA.FAPi (SA.FAPi) has been evaluated as a potential diagnostic probe in diverse epithelial cancers and compared to the standard-of-care 18F-FDG.

METHODS

25 patients enrolled in this prospective study underwent 18F-FDG and 68Ga-SA.FAPi PET scans on two different days. For biodistribution, standardized uptake values (SUV) were computed by delineating region-of-interest on various body organs. For comparative analysis in disease identification, lesion tracer uptake was quantified using SUVs corrected for lean body mass (SUL), SUVmax, tumor-to-background ratio (TBR) with liver and blood pool as the reference, total lesion glycolysis (TLG for 18F-FDG) and total lesion FAP expression (TLF for 68Ga-SA.FAPi).

RESULTS

25 patients (mean age: 58 ± 8 years) with four types of cancers including hepatocellular carcinoma (HCC, 56% of cohort), gall bladder carcinoma (GB Ca, 12%), adrenocortical carcinoma (ACC, 16%), and breast carcinoma (breast Ca, 16%) were prospectively evaluated. Physiological tracer uptake of 68Ga-SA.FAPi was noted in the salivary glands, thyroid, liver, pancreas, muscles and kidneys with variable uptake in the lacrimal glands, extra-ocular muscles, oral mucosa and uterus. Lesion-based comparative analysis between both the radiotracers demonstrated complete concordant findings in detection of all primary lesions and distant metastases in liver, bones, adrenals and peritoneum whereas discordant findings were noted in lung nodules (20%) and lymph nodes (13%). In overall analysis, 68Ga-SA.FAPi exhibited significantly higher SUVmax (10.3 vs 8.8, p-0.019), SULpeak (6.8 vs 4.9, p-0.000) and SULavg (5.4 vs 4.1, p-0.019) in comparison to 18F-FDG whereas TBR was comparable for both the tracers [TBRLiver: median 1.9 (IQR: 2.6-1.4) vs 1.8 (2.6-1.1), p-0.275; TBRBloodpool: 2.1 (3.7-1.4) vs 2.0 (2.7-1.4), p-0.207]. In subcategorical analysis, 68Ga-SA.FAPi demonstrated higher SUVmax, SULpeak and SULavg values for primary disease (SUVmax: 14.8 (18.7-9.7) vs (12.9-6.6), p-0.087; SULpeak: 8.2 (11.2-6.8) vs 6.3 (8.5-4.4), p-0.037; SULavg: 6.9 ± 2.5 vs 5.1 ± 2.2, p-0.023] and distant metastases (8.8 vs 7.2, p-0.038); 6.3 (8.8-4.4) vs 3.6 (4.4-2.0), p-0.000; 5.4 vs 3.5, p-0.000] whereas comparable values were noted for both the tracers in nodal metastases [9 (13.5-4.1) vs 8 (12.7-4.7), p-0.726; 4.5 (6.2-1.8) vs 4.3 (5.7-2.2), p-0.727; 4.1 ± 2.3 vs 3.7 ± 1.8, p-0.129]. In primary disease, highest 68Ga-SA.FAPi avidity was noted in ACC followed by GB Ca and HCC. In distant metastases, gall bladder, lung and skeletal lesions demonstrated higher 68Ga-SA.FAPi avidity. Moreover, 68Ga-SA.FAPi identified five additional lung lesions which were missed by 18F-FDG in one case of ACC.

CONCLUSION

68Ga-SA.FAPi emerged as an effective, versatile diagnostic probe for imaging various epithelial malignancies similar to 18F-FDG.

Radiation Exposure to the Personnel Performing Myocardial Blood Flow Quantification Study Using 13N-ammonia Positron Emission Tomography/Computed Tomography

Purpose

The present study aimed to evaluate radiation exposure to staff performing coronary flow reserve (CFR) measurement using 13N-ammonia.

Materials and Methods

The radiation exposure rate during the administration of 13N-ammonia for the rest and stress part of the study was noted using an ionization chamber-based calibrated survey monitor. The radiation exposure to persons involved in dispensing radioactivity (D1), administering radioactivity (D2) and monitoring the patient during pharmacological stress (D3) were measured using an energy compensated Si-diode personal pocket dosimeter.

Results

The average dose received by individuals with dosimeters D1, D2, and D3 was 1.28 ± 0.79 µSv, 1.56 ± 0.51 µSv, and 0.88 ± 0.97 µSv per injection, respectively, during the rest of study and 1.56 ± 0.96 µSv, 2.64 ± 1.22 µSv, and 2.2 ± 1.7 µSv per injection, respectively, during stress study. The average exposure rate during the administration of 13N-ammonia at 0.5 m and 1.5 m from the injection site was found to be 259 µSv/h and 53.4 µSv/h, respectively, during the rest study and 301 µSv/h and 67.25 µSv/h, respectively, during stress study.

Conclusion

The exposure to the staff performing CFR study with 13N-ammonia was well within prescribed limits by the International Commission on Radiological Protection 103. The CFR measurement with 13N-ammonia positron emission tomography/computed tomography can be included in routine workups of cardiac patients without the fear of radiation exposure.

68 Ga-DOTA.SA.FAPI as a Potential, Noninvasive Diagnostic Probe for Recurrent and Metastatic Adrenocortical Carcinoma : A Head-to-Head Comparison With 18F-FDG

ABSTRACT

Metastatic or recurrent adrenocortical carcinoma (ACC) is a potentially fatal malignancy, which poses major challenges in disease management owing to lack of effective systemic therapies. The drastically reduced survival rates require prompt identification of selective molecules for development of targeted therapeutics. We evaluated the squaric acid containing FAPI derivative, DOTA.SA.FAPI (FAPI), as a potential diagnostic probe in 2 cases of histopathologically proven metastatic and recurrent ACC. Both patients underwent 18 F-FDG and 68 Ga-FAPI PET/CT scans for comparative analysis. 68 Ga-DOTA.SA.FAPI emerged as an excellent diagnostic agent for ACC and performed similar to 18 F-FDG.

Potential Role of 68Ga-NOTA-Duramycin PET/CT Imaging for Early Response Evaluation in a Lymphoma Patient: A Case Report

ABSTRACT

Duramycin, a 19 amino acids peptide, is known for its potential to target phosphatidylethanolamine. During cell death (apoptosis), rearrangement of membrane phospholipids results in the externalization of phosphatidylethanolamine to the outer leaflet of the cell membrane, which can be imaged using 68Ga-NOTA-duramycin. We report 68Ga-NOTA-duramycin imaging in a 50-year-old man with biopsy-proven diffuse large B-cell lymphoma planned for anthracycline-based chemotherapy. 68Ga-NOTA-duramycin PET/CT imaging along with 18F-FDG PET/CT was performed before and after 2 cycles of chemotherapy. The tracer avidity in interim 68Ga-NOTA-duramycin PET/CT showed its diagnostic potential to assess early response to chemotherapy.

18F-NaF PET uptake characteristics of coronary artery culprit lesions in a cohort of patients of acute coronary syndrome with ST-elevation myocardial infarction and chronic stable angina: A hybrid fluoride PET/CTCA study

BACKGROUND

18F-NaF PET/CT identifies high-risk plaques due to active calcification in coronary arteries with potential to characterize plaques in ST-elevation myocardial infarction (MI) and chronic stable angina (CSA) patients.

METHODS

Twenty-four MI and 17 CSA patients were evaluated with 18F-NaF PET/CTCA for SUVmax and TBR values of culprit and non-culprit plaques in both groups (inter-group and intra-group comparison), and pre- and post-interventional MI plaques sub-analysis.

RESULTS

Culprit plaques in MI patients had significantly higher SUVmax (1.6; IQR 0.6 vs 1.3; IQR 0.3, P = 0.03) and TBR (1.4; IQR 0.6 vs 1.1; IQR 0.4, P = 0.006) than culprit plaques of CSA. Pre-interventional culprit plaques of MI group (n = 11) revealed higher SUVmax (P = 0.007) and TBR (P = 0.008) values than culprit CSA plaques. Culprit plaques showed significantly higher SUVmax (P = 0.006) and TBR (P = 0.0003) than non-culprit plaques in MI group, but without significant difference between culprit and non-culprit plaques in CSA group. With median TBR cutoff value of 1.4 in MI culprit plaques, 6/7 plaques (85.7%) among the event prone non-culprit lesions had TBR values > 1.4 in CSA group.

CONCLUSION

The study shows higher SUVmax and TBR values in MI culprit plaques and comparable TBR values for event prone plaques of CSA group in identifying high-risk plaques.

Evaluation of Radiation Exposure to the Patients Undergoing Positron Emission Tomography/Computed Tomography-Guided Biopsies

Purpose

We aimed to evaluate the radiation exposure to patients undergoing positron emission tomography/computed tomography (PET/CT)-guided biopsies.

Materials and Methods

Patients undergoing PET/CT-guided biopsy were recruited prospectively from October 2019 to April 2020. PET/CT-guided biopsy from a tracer avid site was done using an automated-robotic-arm 1 h after intravenous injection of F-18-fluorodeoxyglucose (FDG) (2-5 mCi) or Ga-68-PSMA (1-4 mCi). Regional CT-images were acquired for biopsy planning and confirmation of needle placement. The internal radiation exposure due to the PET component was estimated using the value of activity injected and dose-coefficient for FDG and PSMA. The external radiation exposure due to the CT component was estimated using the value of dose length product and organ coefficients conversion factor. The total effective dose during the procedure was calculated by adding exposure due to both CT and PET components. Percentage contribution from CT and PET component to total effective dose was compared using a paired t-test.

Results

A total of 101 patients (76 males) were recruited for PET/CT-guided biopsy using FDG (n = 79) and PSMA (n = 22). The mean effective-dose due to PET and CT components and total effective-dose was 2.49 ± 1.02 mSv, 2.35 ± 1.03 mSv and 4.83 ± 1.90 mSv, respectively, for FDG-guided procedures and 1.60 ± 0.57 mSv, 3.06 ± 1.36 mSv, and 4.66 ± 1.37 mSv for Ga-68-PSMA-guided procedures. The percentage contribution of PET and CT in total effective-dose was comparable in F-18-FDG and Ga-68-PSMA PET/CT-guided biopsy procedures; however, for Ga-68-PSMA PET/CT-biopsies, CT contributed a higher radiation dose than PET component.

Conclusion

PET/CT-guided biopsy is a safe interventional procedure, and radiation exposure to the patients was less than routine whole-body PET/CT-imaging.

Study of human knowledge and attitude toward urban birds in Faisalabad city, Pakistan

Birds are very valuable indicators of species richness and endemic patterns in a specified ecosystem, which eventually help the scientist to measure the environmental degradation. The aim of present study was to know human knowledge and attitude toward urban birds in Faisalabad city, Pakistan. The study conducted in four consecutive months: November 2019 to February 2020. Population of birds was noted from eight residential towns of Faisalabad city, data were collected through questionnaire. Faisalabad has a reasonably large population of birds and present data show that, there is a significant difference between favorite bird of residential areas and institutions. The pigeon received the most likeness in bird population among residential area residents, while the myna received the least. The most popular bird in Faisalabad institutions was the sparrow, while the least popular bird was the common myna. Bird adaptation percentage of residential areas and institutional areas of Faisalabad was the highest for parrot and sparrow respectively. People in residential areas and institutions, on the other hand, adapted least to common myna. It is concluded that people of the study area like birds and offered food and high population of birds are present in study area.

Prospective Comparison of Angiogenesis-Specific 68Ga-RGD2 PET/CT Imaging Parameters and DAS28-ESR in Rheumatoid Arthritis

OBJECTIVE

The aim of this study was to compare the performance of angiogenesis-specific 68Ga-RGD2 PET/CT with Disease Activity Score 28-erythrocyte sedimentation rate (DAS28-ESR) in assessing disease activity and treatment response in rheumatoid arthritis (RA).

METHODS

This was a prospective study comparing the performance of 68Ga-RGD2 PET/CT and DAS28-ESR in 30 RA patients. All of them underwent 68Ga-RGD2 PET/CT scan from head to toe and clinical examination at the baseline. A repeat scan and clinical examination were done in 27 patients after 3 months of treatment with disease-modifying antirheumatic drugs ± steroids. Three PET parameters, that is, PJC (PET-positive joint count), aSUVmax (average SUVmax), and hSUVmax (highest SUVmax), of positive joints were compared with the DAS28-ESR for disease activity assessment and response evaluation.

RESULTS

Among the 3 PET parameters, PJC showed a significant correlation with the DAS28-ESR (0.64, P < 0.01). A significant change was observed with treatment in the DAS28-ESR and PET parameters of 27 patients at follow-up. There was significant correlation between percentage changes in DAS28-ESR and scan parameters such as PJC (0.689, P < 0.001), aSUVmax (0.712, P < 0.001), and hSUVmax (0.555, P = 0.003) values. The absolute change in aSUVmax value could accurately discriminate (area under the curve, 0.98; P = 0.001) European League Against Rheumatism responders from nonresponders.

CONCLUSIONS

68Ga-RGD2 PET/CT is a promising tool for objective assessment of disease activity and treatment response in patients with RA.

Development of Ga-68 DOTA-CRH for PET/CT Imaging of ACTH-Dependent Cushing's Disease: Initial Study

Purpose: Adrenocorticotropic hormone (ACTH)-dependent Cushing's disease accounts for 75% cases of the endogenous Cushing's syndrome. The size of lesion is usually very small, which results in false-negative magnetic resonance imaging (MRI) even after biochemical confirmation of the disease. Corticotrophin-releasing hormone (CRH) the key controller of hypothalamus-pituitary--adrenal axis binds to CRH receptor R1 and R2. CRH R1 is overexpressed in pituitary adenomas. The present study aims to target these overexpressed receptors with Ga-68-DOTA-CRH for noninvasive imaging of ACTH-dependent pituitary adenomas. Materials and Methods: Custom-synthesized 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA)-CRH peptide was purified by high performance liquid chromatography (HPLC) and characterized by mass spectra. Postradiolabeling optimization with Ga-68, quality control tests were carried out to ensure the suitability of Ga-68 DOTA-CRH for intravenous administration. A pilot study consisting of 15 patients including 6 known cases of macroadenoma underwent Ga-68-DOTA-CRH regional brain positron emission tomography/computed tomography (PET/CT). The optimal imaging time and biodistribution studies were performed in five patients' whole-body and serial brain PET/CT imaging. Lesion activity was determined as SUVmax and correlated with CE-MRI and histopathology of excised tissue. Results: A retention time of 11.3 min and mass of 5145 Da was observed on HPLC and mass spectra. Radiolabeling yield of >98% was achieved under optimized conditions using 25-100 μg of conjugated peptide for 10-22 mCi of Ga-68. The quality control results were in agreement with acceptable criteria. Ga-68-DOTA-CRH was able to delineate ACTH secreting corticotropinoma in all 15 patients. Physiological uptake of radiotracer was observed in liver and spleen with diffused marrow activity. Excretion was noted by renal route. Imaging results were in correlation with CE-MRI and histopathology of excised tissue. Conclusion: Ga-68-DOTA-CRH PET/CT is a promising molecular imaging modality for detection of ACTH-dependent microadenoma.

Humanoid Training Phantom for Positron Emission Tomography-Computed Tomography-Guided Percutaneous Biopsy

Positron emission tomography-computed tomography (PET-CT)-guided biopsy is being increasing practiced worldwide with indications in sampling of lung, abdominal, bone lesions, and among others. Training for PET-guided Interventions at select centers is carried out under supervision of an expert on real patients, similar to training for interventional radiology procedures. Simulation center training has been shown to be useful in improving efficiency of resident trainees. We report the development of concept, design, and practical application of a simplified humanoid training phantom for PET-guided interventions.

Molecular Imaging Targeting Corticotropin-releasing Hormone Receptor for Corticotropinoma: A Changing Paradigm

BACKGROUND

Corticotrophin-releasing hormone (CRH) is the major regulator of adrenocorticotrophic hormone (ACTH) secretion from the anterior pituitary and acts via CRH-1 receptors (CRH-1R). Corticotropinoma though autonomous, still retain their responsiveness to CRH and hence, we hypothesize that in vivo detection of CRH-1 receptors on pituitary adenoma using Gallium-68 (68Ga)-tagged CRH can indicate the functionality of adenoma, and combining it with positron emission tomography-computed tomography (PET-CT) can provide requisite anatomical information.

METHODS

Subjects with ACTH-dependent Cushing's syndrome (CS) (n = 27, 24 with Cushing's disease [CD], 3 with ectopic CS [ECS]) underwent 68Ga CRH PET-CT. Two nuclear medicine physicians read these images for adenoma delineation and superimposed them on magnetic resonance imaging (MRI) sella. The information provided was used for intraoperative navigation and compared with operative and histopathological findings.

FINDINGS

68Ga CRH PET-CT correctly delineated corticotropinoma in all the 24 cases of CD, including the 10 cases with adenoma size < 6mm (4 cases were negative on MRI). Corticotropinoma location on 68Ga CRH PET fusion images with MRI were concordant with operative findings and were further confirmed on histopathology. There was no tracer uptake in the pituitary in 2 patients with ECS, while, in another, the diffuse uptake in pituitary suggested ectopic CRH production.

CONCLUSION

68Ga CRH PET-CT represents a novel, noninvasive molecular imaging, targeting CRH receptors that not only delineate corticotropinoma and provides the surgeon with valuable information for intraoperative tumor navigation, but also helps in differentiating a pituitary from an extra-pituitary source of ACTH-dependent CS.

FUNDING

None.

Early Quantification of Salivary Gland Function after Radioiodine Therapy

Purpose of the Study:

Radioiodine (I-131) is used as an effective noninvasive treatment for thyroid malignancies. Salivary gland is one of the most affected nontarget organs. The present study aims to perform early quantification of salivary gland function after I-131 therapy (RIT) for thyroid cancer considering I-131 down-scatter in the Tc-99m window.

Materials and Methods:

A total of 20 patients (6 males and 14 females) with differentiated thyroid carcinoma were enrolled in the study. Baseline dynamic salivary scintigraphy was performed in all patients using 185–370 MBq (5–10 mCi) Tc-99m pertechnetate. Posttherapy, salivary scintigraphy was performed 10–25 days after RIT in the range of 1.85–7.4 GBq (50–200 mCi). Time–activity curves obtained from the pre- and posttherapy dynamic salivary scintigraphy were used for semi-quantitative analysis. Uptake ratio (UR), ejection fraction (EF%), and maximum accumulation (MA%) were calculated by drawing regions of interest of individual parotid and submandibular glands over a composite image, after correcting for down-scatter from I-131 in the Tc-99m window. A paired t-test was used for comparison of the parameters obtained.

Results:

Significant changes were observed in UR and EF% of both parotid and submandibular glands (P < 0.05). No significant changes were found in the value of MA% of left parotid gland and both submandibular glands in the posttherapy scans in comparison to pretherapy scans (P > 0.05). However, significant difference was observed in the MA% of the right parotid gland (P = 0.025).

Conclusion:

Salivary gland function was found to deteriorate after RIT, with the parotid glands affected more than the submandibular glands.

Dynamic 18F-Fluoro-Ethyl-Tyrosine Positron Emission Tomography/ Computed Tomography: A Better Predictor of Isocitrate Dehydrogenase Mutation in Presurgical Evaluations of Glioma

The recent WHO classification of gliomas has incorporated molecular markers such as isocitrate dehydrogenase (IDH) mutation and 1p/19q co-deletion into the ambit of morphological diagnosis, and 18F-fluoro-ethyl-tyrosine (¹⁸F-FET) positron emission tomography (PET) has shown its utility in noninvasive glioma grading and prognosis. Both dynamic and static FET PET parameters may assist in predicting the IDH mutational status, but time to peak derived from dynamic data may be a better predictor for IDH status. We present a case of left frontal lobe lesion suggestive of high-grade glioma on magnetic resonance imaging and static ¹⁸F-FET PET images, however, dynamic FET image was suggestive of low-grade IDH1-mutated glioma which was later confirmed on histology and immunohistochemistry.

F-18 fluorocholine positron emission tomography- computed tomography in initial staging and recurrence evaluation of prostate carcinoma: A prospective comparative study with diffusion-weighted magnetic resonance imaging and whole-body skeletal scintigraphy

Prostate cancer (PCa) is one of the major causes of death due to cancer in men. Conventional imaging modalities such as magnetic resonance imaging (MRI) provide locoregional status, but fall short in identifying distant metastasis. C-11 choline F-18 fluorocholine (F-18 FCH) has been shown to be useful in imaging of PCa. The present prospective study evaluates and compares the role of F-18 FCH positron emission tomography-computed tomography (PET-CT) with locoregional MRI and whole-body bone scintigraphy in PCa patients for initial staging and recurrence evaluation. This study included a total of 50 patients. Tc-99m skeletal scintigraphy, F-18 FCH PET-CT, and diffusion-weighted MRI of the pelvic region were performed within a span of 2-3 weeks of each other, in random order. For the primary site, core biopsy findings of the lesion were considered as gold standard. The kappa test was used to measure agreement between bone scintigraphy, F-18 FCH, and MRI. For comparing Tc-99m bone scintigraphy, F-18 FCH, and MRI, McNemar's test was applied. F-18 FCH PET-CT and MRI were able to detect primary lesion in all initial staging patients. The sensitivity and specificity of F-18 FCH PET-CT versus MRI were found to be 92.8% versus 89.2% and 100 versus 80%, respectively, for the recurrence at the primary site. A total of 55 bony lesions at distant sites were detected on F-18 FCH PET-CT in comparison to 43 bone lesions on whole-body bone scintigraphy. F-18 FCH PET/CT also detected additional lung lesions in 2 patients and abdominal lymph nodes in 12 patients. F-18 FCH PET-CT could detect primary lesions, local metastasis, bone metastasis, and distant metastasis in a single study and is also a useful modality in recurrence evaluation in PCa patients.

Correction of Positron Emission Tomography Maximum Intensity Projection Image Artifact Using Retro Reconstruction Method

Artifacts in positron emission tomography (PET)/computed tomography imaging can result from a number of factors. Presence of imaging artifacts affects interpretation and can sometimes render the image uninterpretable. Correction of artifacts can be attempted by reprocessing of data. In the present study, one PET maximum intensity projection image artifact was corrected by employing the method of retro-reconstruction.

Age and Gender Differences in COVID 19 Morbidity and Mortality in Nepal

Background The global health community has emphasized the importance of reporting epidemiological data by age and sex groups in the COVID-19 pandemic. However, age and sex disaggregated data of COVID-19 cases and deaths are rarely reported. Such data are very crucial for public to make truly informed choices about their own diseases risk and also for governments for public policy response. Objective To assess age and gender difference among COVID-19 cases and deaths in Nepal. Method This is a retrospective study which uses public data on COVID-19 cases and deaths released by Ministry of Health and Population, Government of Nepal from January to November, 2020. The data analysis was carried out using SPPS software version 26. Result Nepal reported 233,452 confirmed cases and 1,566 deaths of COVID-19 from 23 January 2020 to 30 November 2020. We found statistically significant differences on COVID-19 cases by age and gender in Nepal with higher number of cases among males of economically active age groups (20-60 years). Similarly, we found significant difference in COVID-19 mortality with more death occurred among male group compared to female group and with highest number of deaths among the people of above 60 years. Furthermore, we found differences in cases and deaths among provinces. Conclusion The age and gender differences in COVID cases and deaths in Nepal indicates needs of considering age and sex groups seriously while planning for testing, case management and vaccination against COVID-19 infections in Nepal.

Dose Optimization in 18F-FDG PET Based on Noise-Equivalent Count Rate Measurement and Image Quality Assessment

The present study aimed to optimize the injected dose of ¹⁸F-FDG in whole-body PET/CT scans and assess its effect on noise-equivalent count rate (NECR) and visual image quality (IQ). Methods: Patients scheduled to undergo ¹⁸F-FDG PET/CT were prospectively recruited in the study from January to December 2019, regardless of the indication or underlying disease. Patients were divided into 4 groups and injected with different amounts of ¹⁸F-FDG radioactivity per kilogram of body weight (1.85, 3.7, 5.5, and 7.4 MBq/kg). All patients underwent ¹⁸F-FDG PET/CT studies, and NECR_local was calculated by noting the trues rate, total prompts, and randoms rate for each bed position. Whole-body NECR_global was calculated as the average NECR for all bed positions. IQ was qualitatively assessed for each bed position (IQ_local) and for whole-body PET (IQ_global) by 2 readers using 5-point scores based on prevalence of noise, contrast, and lesion detectability. NECR and IQ were compared among all 4 activity groups. Patients were also subdivided into 4 body-mass-index groups (group I, 15-20 kg/m²; group II, 20.1-25 kg/m²; group III, 25.1-30 kg/m²; and group IV, 30.1-35 kg/m²) for comparison. A P value of less than 0.05 was considered significant. Results: In total, 109 patients underwent ¹⁸F-FDG PET/CT studies after injection of different amounts of ¹⁸F-FDG radioactivity and a mean uptake time of 62.32 min. The mean NECR_global and IQ_global for each group were significantly different from other groups (P < 0.05), with NECR and IQ being higher in high-activity groups than in low-activity groups. The overall IQ was acceptable in all patients, even in the lowest-activity group (1.84 MBq/kg). The mean NECR_global and IQ_global were significantly different in all 4 body-mass-index groups (P < 0.05), except between groups II and III (P > 0.05). NECR_local and IQ_local correlated moderately (r = 0.64). Conclusion: Optimization of injected ¹⁸F-FDG radioactivity from 7.4 MBq/kg (200 μCi/kg) to 1.85 MBq/kg (50 μCi/kg) resulted in acceptable IQ, despite a reduction in NECR.

THU0531 A PROSPECTIVE STUDY EVALUATING THE ROLE OF 68GA-RGD2 PET/CT ANGIOGENESIS IMAGING IN ASSESSING DISEASE ACTIVITY AND TREATMENT RESPONSE IN RHEUMATOID ARTHRITIS AND ITS COMPARISON WITH DAS28

Background:

PET/CT imaging of synovial angiogenesis using68Ga-RGD (cyclic tripeptide agent targeting αvβ3integrin) to study disease activity in rheumatoid arthritis (RA) has been demonstrated earlier in a few patients. However, post treatment changes in disease activity on68Ga-RGD2PET/CT imaging have not been adequately assessed.

Objectives:

To compare the performance of68Ga-RGD2PET/CT with disease activity score (DAS) 28 in assessing disease activity and treatment response in RA.

Methods:

Thirty patients (24F, 6M) aged 43±12 years with clinically diagnosed RA were prospectively studied. After calculation of DAS28 by a rheumatologist, all 30 patients underwent68Ga-RGD2PET/CT scan. Of these, 27 patients underwent a second68Ga-RGD2PET/CT scan and clinical assessment after at least 3 months of treatment. Total body and regional images of the upper limbs were acquired and interpreted by two nuclear medicine physicians blinded to the clinical findings. Joints showing focally increased tracer uptake compared to the background were considered positive and joints showing uptake equal to or less than background were considered negative. Data of 30 patients were used for inter-observer and inter-modality agreement calculations. Changes in PET parameters and DAS28 were compared in 27 patients to assess treatment response.

Results:

Out of 1560 joints examined in the initial scan, 394 were positive on PET/CT compared to 348 on clinical evaluation. Inter-observer agreement between nuclear medicine physicians was excellent (Cohen’s kappa 0.92, p<0.05) and inter-modality agreement between PET and clinical examination was moderate (Cohen’s kappa 0.55, p<0.05). The DAS28 and SUVmax values (highest and average) of 27 patients showed significant reduction on follow-up compared to the initial evaluation. There was significant correlation between percentage change in DAS28 and percentage change in scan parameters like PET positive joint counts (0.689, p<0.001), average SUVmax (0.712, p<0.001) and highest SUVmax values (0.558, p=0.003) of scan-positive joints in 27 patients. Additional advantages of68Ga-RGD2PET/CT included objective assessment, whole body evaluation of all small and large joints, and greater reproducibility.

Conclusion:

68Ga-RGD2PET/CT is a promising tool for objective assessment of disease activity and treatment response in patients with RA.

Table 1.

Clinical and PET parameters of the patients

ParameterInitial data (n=27)Mean (SD)/Median (IQR)Follow-up data (n=27)Mean (SD)/Median (IQR)TJC(28)10 (5-13)3 (2-4)SJC(28)6 (3-7)1 (0-2)ESR25 (20-41)24 (18-35)PtGA6.0 (5.0-6.0)3.0 (2.0-4.0)DAS28(3)5.14 (0.85)3.74 (0.88)DAS28(4)5.60 (0.90)3.80 (0.96)PET positive Joints12 (7-8)4 (2-9)aSUVmax2.08 (1.68-2.52)1.79 (1.00-2.06)hSUVmax3.45 (2.71-4.70)3.34 (1.95-4.25)

TJC/SJC: tender/swollen joint counts; ESR: erythrocyte sedimentation rate; PtGA: patients global assessment scale; DAS: disease activity score; aSUVmax/hSUVmax: average/highest SUVmax (maximum standardized uptake value); SD: standard deviation; IQR: interquartile range

Figure 1.

68Ga-RGD2PET scan of a 26-year female RA patient on treatment.A.Initial scan shows increased tracer uptake in multiple joints of upper and lower limbs and tendon sheaths of hands and ankle region (arrows); DAS28 was 4.56 (moderate disease activity) and ESR 12 mm/1sthour.B. Follow-up scan after 4 months shows resolution of tracer activity in the previously involved joints with only a mild focus persisting in the left knee joint; DAS28 was 1.73 (clinical remission according to ARA) and ESR 08 mm/1sthour.

Acknowledgments:

This study was supported by Indian Council of Medical Research, New Delhi [grant no.3/2/June-2017/PG-Thesis-HRD (23)]

Disclosure of Interests:

None declared

Evaluation of external beam hardening filters on image quality of computed tomography and single photon emission computed tomography/computed tomography

This study was undertaken to evaluate the effect of external metal filters on the image quality of computed tomography (CT) and single photon emission computed tomography (SPECT)/CT images. Images of Jaszack phantom filled with water and containing iodine contrast filled syringes were acquired using CT (120 kV, 2.5 mA) component of SPECT/CT system, ensuring fixation of filter on X-ray collimator. Different thickness of filters of Al and Cu (1 mm, 2 mm, 3 mm, and 4 mm) and filter combinations Cu 1 mm, Cu 2 mm, Cu 3 mm each in combination with Al (1 mm, 2 mm, 3 mm, and 4 mm), respectively, were used. All image sets were visually analyzed for streak artifacts and contrast to noise ratio (CNR) was derived. Similar acquisition was done using Philips CT quality control (QC) phantom and CNR were calculated for its lexan, perspex, and teflon inserts. Attenuation corrected SPECT/CT images of Jaszack phantom filled with 444-555 MBq (12-15 mCi) of (99m)Tc were obtained by applying attenuation correction map generated by hardened X-ray beam for different filter combination, on SPECT data. Uniformity, root mean square (rms) and contrast were calculated in all image sets. Less streak artifacts at iodine water interface were observed in images acquired using external filters as compared to those without a filter. CNR for syringes, spheres, and inserts of Philips CT QC phantom was almost similar to Al 2 mm, Al 3 mm, and without the use of filters. CNR decreased with increasing copper thickness and other filter combinations. Uniformity and rms were lower, and value of contrast was higher for SPECT/CT images when CT was acquired with Al 2 mm and 3 mm filter than for images acquired without a filter. The study suggests that for Infinia Hawkeye 4, SPECT/CT system, Al 2 mm, and 3 mm are the optimum filters for improving image quality of SPECT/CT images of Jaszack or Philips CT QC phantom keeping other parameters of CT constant.

Paraneoplastic pemphigus as a first sign of metastatic retroperitoneal inflammatory myofibroblastic tumor: (18)F-FDG PET/CT findings

A 30-year-old female presented with a 3-month history of erosive stomatitis and bullous lesions, along with recurrent episodes of abdominal pain. She was found to have a retroperitoneal lump in left lumbar region. Skin biopsy revealed bullous disorder. CT guided biopsy of the retroperitoneal mass was suggestive of inflammatory myofibroblastic tumor (IMT). She was started on oral steroids and supportive care, and surgery was being planned when she developed respiratory failure. CT chest revealed vertebral metastases. PET/CT for whole body work up revealed a left para-aortic mass along with multiple skeletal metastases. The patient was kept on conservative management. After 3 months, the patient has shown clinical improvement, and an exploratory laparotomy is now being planned for the excision of the tumor, followed by chemotherapy. This case of retroperitoneal IMT is rare in terms of skeletal metastases with paraneoplastic pemphigus.

Genetic Diversity Assessment of Acid Lime (Citrus Aurantifolia Swingle) Landraces of Eastern Nepal Using RAPD Markers

Acid lime (Citrus aurantifolia Swingle) is an important commercial fruit crop, cultivated from terai to high hill landscapes of Nepal. However, production and productivity is very low due to various reasons including infestations by various diseases and pests, lack of diseases and pests resistant and high yielding varieties. In this context, determination of genetic variation at molecular level is fundamental to citrus breeders for the development of elite cultivars with desirable traits. In the present study, Random Amplified Polymorphic DNA (RAPD) marker technique has been employed to assess genetic diversity in 60 acid lime landraces representing different agro-ecological zones of eastern Nepal. Nine selected arbitrary primers generated 79 RAPD fragments of which 75 were polymorphic (94.94%). Phenogram was constructed by NTSYSPC ver. 2.21i using UPGMA cluster analysis based on Jaccard’s similarity coefficient to deduce overall genetic diversity and relationships of the acidlime genotypes under study. Sixty acid lime landraces formed seven clusters and similarity value ranged from 38% to 98% with an average of 72%. Genetic variation at different agro-ecological zones was assessed using Popgene ver. 1.32 and found 47% to 69.6% polymorphism. Shannon’s index and Nei’s gene diversity showed highest level of acid lime diversity in Terai zone (PPB, 69.62%; H, 0.213; I, 0.325) followed by mid-hill zone (PPB, 67.09%; H, 0.208; I, 0.317). The results obtained will be useful to citrus breeders for elite cultivar development. The RAPD-PCR technique is found to be the rapid and effective tool for genetic diversity assessment in acid lime landraces of Nepal. DOI: http://dx.doi.org/10.3126/ijasbt.v2i3.10950  Int J Appl Sci Biotechnol, Vol. 2(3): 315-327  

Assessment of Pesticide Residues in Some Vegetables Grown in Kavrepalanchok and Bhaktapur Districts

Pesticides have wide spread use and their toxic residues have been reported in various environmental matrices. Thus, the determination of pesticide residues in food commodities such as vegetables, cereals, fruits, and other environmental components like soil, water has become increasingly essential requirement for consumers, producers and authorities for food quality control. Therefore, monitoring of residue level and exposure assessment of organophosphate group of pesticides namely dichlorovos and methyl parathion was carried out in 30 winter and summer vegetables supplied in Kathmandu valley. It was found that the MRL value of dichlorovos exceeded in three types of vegetables whereas in case of methyl parathion the MRL value exceeded in two types of vegetables only. The estimated average daily intake (EADI) of dichlorovos exceeded the acceptable daily intake (ADI) in 18 vegetables, whereas, regarding methyl parathion the EADI exceeded the ADI in 10 types of vegetables. Nepal Journal of Science and Technology Vol. 13, No. 2 (2012) 45-50 DOI: http://dx.doi.org/10.3126/njst.v13i2.7713

Relationship between apoptosis and the number of macrophages in eutopic endometrium from women with and without endometriosis

OBJECTIVE

To investigate the relationship between apoptotic cells and macrophages in the eutopic endometrium of women with and without endometriosis.

DESIGN

Retrospective analysis of archival uterine endometrial biopsy specimens.

SETTING

Institute for the Study and Treatment of Endometriosis, and university-based pathology and research laboratories.

PATIENT(S)

Fifty-one women with endometriosis and 24 healthy control subjects without endometriosis.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

The number of TUNEL+ (terminal deoxynucleotide transferase [TdT]-mediated deoxyuridine triphospate [dUTP] nick end-labeling-positive) (apoptotic) cells and CD68+ (CD68 positive) (macrophages).

RESULT(S)

Apoptotic cells and macrophage numbers were positively correlated in the eutopic endometrium of women with and without endometriosis. However, the number of apoptotic cells and the macrophage content in the endometrium of women with endometriosis was significantly reduced compared with that of healthy control subjects without endometriosis. Differences between apoptosis and macrophage numbers between the two populations were observed predominantly during the early proliferative phase of the menstrual cycle.

CONCLUSION(S)

The reduction in apoptosis described for endometrial cells in women with endometriosis may be related to reduced macrophage trafficking into the eutopic endomtrium during the early-proliferative phase of the menstrual cycle.

Retroperitoneal subpancreatic ectopic pregnancy following in vitro fertilization in a patient with previous bilateral salpingectomy: how did it get there?

An unusual case of retroperitoneal ectopic pregnancy is reported. The patient, a 34 year old nulligravida, underwent IVF/ET following bilateral salpingectomy. A small, degenerating, intrauterine gestational sac suggested failing intrauterine pregnancy. There was no intraperitoneal free fluid. On Day 41 after ET, the patient was hospitalized because of acute epigastric pains. A pseudocyst of the head of pancreas was demonstrated by CT scan. A day later, exploratory laparotomy, because of a precipitous drop in the hemoglobin, revealed a massive retroperitoneal hematoma and an embryo in the gestational sac attached to the head of pancreas and major blood vessels. The patient did well following surgery. The mechanisms of retroperitoneal embryo migration are discussed and literature is reviewed.

Apoptosis in endometrial glandular and stromal cells in women with and without endometriosis

BACKGROUND

The aetiology of endometriosis is unknown. Ectopic dissemination of the endometrial cells gives origin to endometriotic lesions, but occurs in women with and without endometriosis. It has been suggested that increased ectopic cell survival facilitates their implantation. The objectives of this study were to evaluate endometrial apoptosis in women with endometriosis according to: (i) cyclic changes, (ii) glandular and stromal contribution, and (iii) stage of the disease.

METHODS

The subjects were women undergoing diagnostic laparoscopy and endometrial biopsies for suspected endometriosis. Spontaneous apoptosis was evaluated using TdT-mediated dUTP-biotin nick end-labelling (TUNEL) assay. Apoptotic cells per 10 mm(2) (apoptotic index) in an area of 10-50 mm(2) in 5 microm endometrial tissue sections were counted and location of these cells was recorded.

RESULTS

The apoptotic index in glandular epithelium was lower in endometriosis than controls (26.0 +/- 5.5 versus 51.2 +/- 9.7, P = 0.03) but not in the stroma (36.3 +/- 6.4 versus 48.4 +/- 11.3, NS). In controls, apoptosis was highest during the late secretory/menstrual and early proliferative phases and cyclic variability was apparent. In endometriosis, this cyclic variability was lost. There was a trend toward decreased apoptosis with increasing stage of the disease, but the differences lacked statistical significance.

CONCLUSIONS

Spontaneous apoptosis is decreased in the endometrial glands in women with endometriosis, especially during late secretory/menstrual and early proliferative phases of the cycle. This may indicate increased viability of endometrial cells shed during menses, facilitating their ectopic survival and implantation.

Postlaparoscopic small bowel obstruction secondary to unrecognized nodular endometriosis of the terminal ileum

Small bowel involvement by endometriosis occurs in about 0.5% of patients, but nodular endometriosis involving the entire wall of the terminal ileum is extremely rare. Endometriotic nodules protruding into the intestinal lumen may lead to chronic, partial, or acute complete small bowel obstruction and associated clinical changes. If obstruction is partial, preoperative diagnosis is difficult and seldom suspected, and no reliable diagnostic tests are available. At laparoscopic surgery, performed typically for associated pelvic endometriosis, bowel lesions may easily be overlooked, especially in women with abdominal adhesions from earlier surgery. Surgical injury, tension tears, or postoperative edema may contribute in such cases to the development of acute, complete small bowel obstruction, which may be difficult to differentiate from postoperative ileus. The patient may deteriorate rapidly and develop abdominal sepsis and multiple organ failure with high risk of mortality. Because of increased production of tumor necrosis factor-alpha by autologous monocytes, endometriosis may predispose to development of severe sepsis and septic shock. (J Am Assoc Gynecol Laparosc 8(1):161-166, 2001)

Open laparoscopy: 29-year experience

OBJECTIVE

To describe the safety and efficacy of open laparoscopy as a method of access to the abdominal cavity for laparoscopic surgery.

METHODS

We reviewed retrospectively all cases of open laparoscopy we did between August 1970 and June 1999.

RESULTS

Twenty-seven (0.5%) of 5284 patients who had open laparoscopies during the study years developed complications related to primary access. Twenty-one had minor wound infections, four had minor hematomas, one developed an umbilical hernia that required reoperation, and one had an inadvertent injury to the small bowel that was repaired intraoperatively without adverse outcome. Access to the abdominal cavity was generally secured in 3-10 minutes.

CONCLUSION

Open laparoscopy was associated with no method failure or life-threatening complications. Minor and medium risk complications occurred at a rate of 0.5%. Open laparoscopy is a safe, effective method of accessing the abdominal cavity.