Asia Oceania Journal of Nuclear Medicine and Biology最新文献

Primary Sjögren syndrome (SS) is an autoimmune disease affecting exocrine glands, with predisposition to development of lymphoma (lymphomagenesis). We report a case of Sjogren's syndrome and discuss the role of FDG PET/CT in the primary diagnosis of lymphoma transformation in SS. Furthermore, we reviewed the literature regarding the utility of FDG PET/CT to assess systemic disease activity and also its role in the SS associated lymphoma with light into the new PET tracers that can be explored for these indications in the future. Published data suggest promising role of FDG PET/CT in SS associated lymphomas, and demands larger studies for its establishment.

Objectives: to investigate the capability of ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography ([¹⁸F]-FDG PET/CT) derived volumetric parameters to predict human epidermal growth factor receptor 2 (HER2) status in breast cancer patients.

Methods: retrospective study enrolled 47 female patients with breast cancer. All patients had pretreatment [¹⁸F]-FDG PET/CT. Clinical data, pathology report and HER2 status were retrieved from medical records. In an attempt to assess the predictive value of the PET-derived metabolic parameters, Receiver operating characteristic (ROC) curve was constructed with area under curve analysis performed to detect best cutoff value of significant parameters for detection of HER2 positive.

Results: No statistically significant difference was noted among both groups (HER2 positive and negative) in respect to age, menopausal status, histology, grade, T-stage, N-stage, or antigen Kiel 67 (Ki-67) index. ROC curve successfully marked cutoff point ≥42.35 for total lesion glycolysis (TLG) and  12.75 for metabolic tumor value (MTV) that are capable to discriminate positive versus negative HER2 expression in breast cancer patients with area under curve (AUC) 0.728 and 0.723 and P-values 0.002 and 0.004 respectively. Such cutoff point was not deduced for standard uptake value (SUV) max. Primary tumor TLG cutoff correlated well with age where 77.8% of patients with TLG  42.35 were older than 45 years old compared to 22.2% of them who were younger than 45 years, P-value0.047. Also 70.3% of patients with TLG exceeds  42.35 had T3 and 4 primary tumors while 65% of those with TLG <42.35 their primary tumors were T1 and 2, P-value0.03. As regards Primary tumor MTV cutoff point, significant correlations were noted in respect to T-stage where 78.2% of the patients with primary tumor MTV  12.75 were T3 and 4, compared to 66.6% of those with primary tumor MTV <12.75 were T1 and 2, P-value0.011.

Conclusion: PET-derived volumetrics may serve as non-invasive predictors of biological processes represented here as HER2 expression in breast cancer patients.

Objectives: Gastroparesis is a complication following lung transplantation. This study aimed to assess the prevalence of gastroparesis in patients with lung transplants undergoing solid phase gastric emptying scintigraphy (GES). Specifically, we investigated which type of lung transplant is more susceptible to gastroparesis and whether timing of GES post-transplantation impacts diagnosis of severe gastroparesis.

Methods: This retrospective analysis included lung-transplant recipients between January 2008 and February 2024, who underwent GES. Patients received a standardized egg sandwich labeled with 500 uCi Technetium-99m sulfur colloid. GES results were compared to normal values for percentages retained at 2- and 4-hours post-meal.

Results: Among 485 lung-transplant recipients, 111 (50% male; mean age 63 years) underwent posttransplant GES. Gastroparesis was diagnosed in 23% of lung transplant recipients during the study period. Of those who underwent GES, 67% exhibited delayed gastric emptying, with 38 patients (34%) demonstrating severe retention (>30% at 4 hours). Delayed gastric emptying rates were highest in bilateral lung transplant recipients (73%), followed by left (66%) and right (56%) lung transplant recipients. Timing of GES beyond 6 months or one-year post-transplant did not significantly increase the incidence of delayed gastric emptying (p>0.05). There was no significant difference in proportion of patients with delayed gastric emptying when patients were stratified by gender and age.

Conclusions: Our findings suggest that laterality of lung transplant does not influence risk of delayed gastric emptying. Moreover, early evaluation of gastrointestinal symptoms with GES did not impact the severity or rate of gastroparesis. We recommend routine screening with GES for symptomatic lung transplant recipients, irrespective of transplant timing, to facilitate timely management and reduce post-operative complications associated with gastroparesis.

Objectives: This study evaluated the necessity of a ventilation scan in patients suspected of PE with a history of COVID-19 infection.

Methods: This was a cross-sectional study of patients with PCR-confirmed COVID-19 and suspected PE at a tertiary care hospital in 2020. They underwent ventilation/perfusion (V/Q) scintigraphy using single-photon emission computed tomography/computed tomography (SPECT/CT) and CT scans with or without contrast. Two blinded nuclear medicine physicians interpreted the images for PE and COVID-19. Clinical and laboratory data were extracted and analyzed.

Results: 96 patients with suspected PE and COVID-19 infection. The study excluded eight patients who could not undergo ventilation scans and confirmed PE in five patients with multiple mismatched V/Q defects on SPECT/CT. The study ruled out PE in 83 patients who had either regular perfusion scans, perfusion defects with COVID-19 features, or matched V/Q defects. The study found that the prevalence of PE was 5.68%, and the necessity of ventilation scans was 28.40% in this population.

Conclusion: It was found that PE was present in 5.68% of the patients, and ventilation scans were needed for 28.40% of the patients to confirm or exclude it.

Objectives: ¹⁸F-FDG PET/CT has been used to characterize the primary lesion and staging in head and neck cancers (HNC). However, prior studies for detecting distant metastasis and synchronous tumors are sparse, especially in Indian context. To investigate the frequency and distribution of head and neck carcinomas, distant metastases and synchronous malignancies detected in HNC in a north Indian population.

Methods: Medical records and whole body ¹⁸F-FDG PET/CT examinations performed for initial staging on a total of 281 newly diagnosed HNC patients between 01/2019 to 31/6/2023 in North India were retrospectively analyzed and reviewed to look for distant metastasis and synchronous tumors.

Results: On whole body ¹⁸F-FDG PET/CT, distant metastases were detected in 33 (11.7%) patients, all with locally advanced primary tumors corresponding to T category 3 and 4. Lung (6%) and bone (~6.7%) were the most common sites of distant metastasis. In nine patients metastases were detected below the diaphragm. Synchronous malignancies were discovered and histopathologically proven in 22 (7%) patients. Lung carcinoma was the most common synchronous tumor, detected in 9 patients. In seven patients synchronous tumour was detected outside the aerodigestive tract, of which four were below the diaphragm.

Conclusions: Of the distant metastasis diagnosed in 11.7% of HNC patients with TNM tumor category T3 and T4, 3% of metastasis lesions were detected below the diaphragm. Synchronous malignancy was diagnosed in 7% patients irrespective of primary HNC stage. These findings demonstrate the advantage of using whole body ¹⁸F-FDG PET/CT as an ideal and preferred modality for initial staging and screening of HNC patients since detection of distant metastasis or a synchronous malignancy changes the management approach in these patients.

Objectives: Liver malignancies are among the most prevalent causes of cancer-related deaths worldwide. Intra-arterial administration of particulates labeled with beta-emitting radionuclides is one of the non-surgical promising modalities for the treatment of liver cancer.

Methods: In this work, the radiation absorbed dose of ¹⁶⁶Ho-hydroxyapatite (¹⁶⁶Ho-HA) radiopharmaceutical was estimated for adult men based on biodistribution data in normal Wistar rats. The MIRD dose calculation method and the Sparks and Aydogan methodology were applied.

Results: The results show that more than 84% of the absorbed dose is localized in liver tissue (7.35 mGy MBq^-1). Also, radiation absorbed doses of ¹⁶⁶Ho-HA for red bone marrow, osteogenic cells, and spleen tissues were estimated to be about 0.18, 0.38, and 0.24 mGy MBq^-1, respectively. The maximum administrated activity was obtained at 87.5 MBq kg^-1 of body weight with an effective dose of 0.39 mSv MBq^-1. The maximum tolerable dose (MTD) for liver tissue was 6.13 GBq (165.56 mCi).

Conclusion: This study indicated that ¹⁶⁶Ho-HA can provide an impressive dose for liver cancer malignancies with an insignificant dose to healthy tissues.

Objectives: This study aimed to evaluate the quality and associated quantitative values of bone single-photon emission computed tomography (SPECT) with and without SwiftScan using a semiconductor camera equipped with a cadmium-zinc-telluride detector.

Methods: Ten patients with bone metastases from prostate cancer who underwent list-mode SPECT/computed tomography using a whole-body semiconductor camera participated in this study. A total of 130 metastatic lesions from 10 patients were analyzed. Standard SPECT images were obtained approximately 3 h later, and the images were constructed with and without SwiftScan.

Results: The visual assessment of 3-dimensional maximum intensity projection images showed that when an image quality score of 4 (good) or better was considered clinically acceptable, it was maintained at 4 or better in the 75% and 50% scans with SwiftScan, whereas only the 75% scan was considered acceptable without SwiftScan. The intraclass correlation coefficient was 0.952 at 5% for the standard time without SwiftScan and 0.990 with SwiftScan. The maximum standardized uptake value (SUV_max) changes were 0 to 9.5 (median 1.1) at 75%, 0.1 to 11.5 (1.65) at 50%, 0 to 15.7 (2.1) at 25%, 0.1 to 33.2 (4.2) at 10%, 0.2 to 8.9 (5.65) at 5% without SwiftScan. On the contrary, the SUV_max changes in absolute value were 0 to 5.4 (median 0.8) at 75%, 0 to 6.5 (1.4) at 50%, 0 to 19.1 (1.7) at 25%, 0 to 24.2 (2.8) at 10%, 0 to 29.9 (2.6) at 5% with SwiftScan. The contrast-to-noise ratios (CNR) were 95.3 at 75%, 88.3 at 50%, 69.2 at 25%, 45.7 at 10%, and 31.6 at 5% without SwiftScan, and 96.9, 91.7, 78.0, 71.6, and 62.0, respectively, using SwiftScan.

Conclusion: With the use of SwiftScan, a 50% reduction in acquisition time was considered acceptable for image quality with reproducible quantitative indices such as SUV_max and CNR.

Objectives: Brain perfusion single-photon emission computed tomography (SPECT) image quality varies depending on SPECT systems. This study aimed to evaluate the relationship between physical parameters and visual analysis for assessment of the brain SPECT image quality. We conducted our phantom study under various conditions in a multi-center and multi-vendor study.

Methods: SPECT images of the brain phantom were acquired from eight devices in five institutions. The phantom was filled with 28 kBq/ml of ^99mTc solution at the start of scanning. We obtained various data with different acquisition times under clinical reconstruction and acquisition conditions at each institution. Four physical parameters (percent contrast, contrast noise ratio (CNR), asymmetry index (AI), and sharpness index (SI)) were measured with the phantom. Seven observers blindly evaluated all image series and scored them on a scale of 1-3 using four checkpoints: contrast, image noise, symmetry, and sharpness. The average score for all observers was calculated.

Results: CNR increased with increasing visual analysis scores for contrast and image noise, both of which were significantly different between the group with scores "<2" and the group with scores "≥2 and <3". AI decreased as the visual analysis score for symmetry increased, and the AI of both groups with scores "≥2 and <3" and "3" were significantly lower than that of the group with scores "<2". Conversely, no relationship with visual analysis was found for percent contrast and SI.

Conclusion: We clarified the relationship between physical parameters and visual analysis of a brain phantom in a multi-center and multi-vendor study. CNR and AI showed agreement with visual analysis.

Breast cancer lymphoscintigraphy is a crucial tool in pre-operative assessment, typically revealing sentinel lymph node drainage patterns within axillary and extra-axillary regions. However, rare cases challenge conventional understanding. We report a 67-year-old woman with breast cancer, where lymphoscintigraphy revealed focal uptake within the falciform ligament of the liver, an exceedingly rare phenomenon. Clinical examination and imaging showed no axillary lymph node involvement. Lymphoscintigraphy and subsequent Single-photon emission computed tomography (SPECT)/computed tomography (CT) uncovered two axillary lymph nodes and an atypical focal uptake in the falciform ligament. Histopathology revealed no metastasis in sentinel nodes. The conventional understanding of breast lymphatic drainage primarily involves axillary and extra-axillary pathways, with the falciform ligament rarely implicated. This case suggests a unique lymphatic pathway connecting the breast and liver, possibly influencing metastasis. Factors such as lymphatic obstruction and valvular incompetency may contribute. This case highlights the importance of comprehensive lymphatic mapping in breast cancer evaluation and underscores the need for further research into atypical lymphatic pathways.

Objectives: To compare the diagnostic performance of [⁶⁸Ga]-Ga-FAPI-46 and [¹⁸F]-FDG PET/CT imaging for the detection of lesions and disease staging in breast cancer.

Methods: Twelve female patients with breast cancer (mean age= 49.2±13.29 years) and previous [¹⁸F]-FDG PET/CT were recruited in the study. [⁶⁸Ga]Ga-FAPI-46 imaging performed in all patients within one month after [¹⁸F]-FDG PET/CT imaging. The acquired PET/CT data with both tracers were reconstructed. Tracer avid lesions with each PET tracer were identified and the semi-quantitative parameters i.e. SUV_max, lesion counts and target-to-background ratio (TBR_max) were analyzed.

Results: Physiologic distribution of [⁶⁸Ga]-Ga-FAPI-46 was observed in the liver, blood pool and kidneys, whereas no tracer uptake was noted in the brain and heart. The mean liver SUV_max for [⁶⁸Ga] Ga-FAPI-46 was 1.5±0.1 which was lower than that noted for [¹⁸F]-FDG PET/CT (2.9±0.2). Likewise, the mean blood pool SUV_max value for [⁶⁸Ga]-Ga-FAPI-46 was lower than [¹⁸F]-FDG PET/CT (1.7±0.1 versus 2.0±0.1). [⁶⁸Ga]-Ga-FAPI-46 PET/CT demonstrated higher tracer uptake in the lesions detected in the brain, bone, internal mammary and lymph nodes in 4/12 patients. The overall lesions detections and the mean SUV_max values did not differ significantly between the two techniques. On the other hand, [⁶⁸Ga]-Ga-FAPI-46 demonstrated higher mean TBR_max than [¹⁸F] FDG PET/CT particularly for lesions detected in kidneys, chest wall, mediastinum, and musculoskeletal lesions. However, both techniques offered identical TNM staging.

Conclusion: The findings of this preliminary study demonstrated that [⁶⁸Ga]-Ga-FAPI-46 and [¹⁸F]-FDG PET/CT offered identical disease staging in the breast cancer patients. [⁶⁸Ga]-Ga-FAPI-46 showed lower liver and blood pool uptake and an enhanced tumor-to-background ratio, thereby suggesting its potential for improved lesions detection. This may open opportunity for emerging FAP based radioligand for therapeutic applications in advanced stage breast cancers. However, this needs validation in a larger number of patients.