The value of quantitative analysis of radionuclide bone SPECT/CT imaging in vertebral compression fracture: a retrospective study.

BACKGROUND: Most patients with osteoporosis experience vertebral compression fracture (VCF), which significantly reduces their quality of life. These patients are at a high risk of secondary VCF regardless of treatment. Thus, accurate diagnosis of VCF is important for treating and preventing new fractures. We aimed to investigate the diagnostic and predictive value of quantitative bone imaging techniques for fresh VCF. METHODS: From November 2021 to March 2023, 34 patients with VCF were enrolled in this study, all of whom underwent routine 99mTc-MDP whole-body bone planar scan and local SPECT/CT imaging. The maximum standard uptake value (SUVmax) of 57 fresh VCF, 57 normal adjacent vertebrae, and 19 old VCF were measured. Based on the site of the fracture, fresh VCFs were regrouped into the intervertebral-type group and the margin-type group. Meanwhile, 52 patients who had no bone metastasis or VCFs in their bone scan were assigned to the control group. The SUVmax of 110 normal vertebral bodies and 10 old VCFs in the control group were measured. RESULTS: The median SUVmax of fresh VCF was 19.80, which was significantly higher than the SUVmax of other groups. The receiver operator characteristic (ROC) curve showed that the cut-off value of SUVmax was 9.925 for diagnosing fresh VCF. The SUVmax in the intervertebral-type group was significantly higher than that in the margin-type group (P = 0.04). The SUVmax of normal vertebrae was higher among patients than among the control group (P<0.01), but the CT HU value showed no significant difference. CONCLUSION: The quantitative technique of bone SPECT/CT has a significant value in diagnosing fresh VCF. It can also determine the severity of fractures. In addition, whether the SUVs of the vertebrae adjacent to the fractured vertebra can predict re-fracture deserves further studies.

99mTc-FAPI-04 SPECT/CT outperforms contrast-enhanced CT in detecting metastasis in postoperative patients with colorectal cancer.

Purpose: To compare the performance of 99mTc-FAPI-04 SPECT/CT and contrast-enhanced CT (CECT) in the detection of postoperative metastasis in patients with colorectal cancer (CRC). Methods: The postoperative patients with CRC were consecutively recruited from January 2023 to June 2023, and the enrolled patients completed 99mTc-FAPI-04 SPECT/CT imaging and CECT examination within two weeks. Histopathological analysis and the follow-up results were used as the reference criteria. The location and number of metastatic sites and the detection accuracy between the two imaging methods were compared. The tumor-to-background ratio (TBR) of liver metastasis and lymph node metastasis in 99mTc-FAPI-04 SPECT/CT imaging were also calculated for comparison. Results: In total, 19 postoperative CRC patients, including 15 patients with metastasis, were included in this study. In the patient-based analysis, 99mTc-FAPI-04 SPECT/CT showed a significantly higher sensitivity for the detection of metastasis than CECT (93.3% vs. 80.0%, p = 0.038), but both techniques had the same specificity (100%, 4/4). For the lesion-based analysis, the detection rates of metastatic sites were 92.2% (47/51) and 72.5% (37/51) for 99mTc-FAPI-04 SPECT/CT and CECT, respectively, and the difference between them was statistically significant. In the diagnosis of liver metastasis and lymph node metastasis, 99mTc-FAPI-04 SPECT/CT both exceeded CECT. Additionally, the TBR in lymph node metastasis was higher than that in liver metastasis. Conclusion: The findings suggested that 99mTc-FAPI-04 SPECT/CT could detect metastasis more effectively than CECT, especially liver and lymph node metastases, in postoperative CRC patients.

Offloading effect in the unoperated contralateral knee after unilateral medial open wedge high tibial osteotomy: A SPECT/CT analysis.

BACKGROUND: An open wedge high tibial osteotomy (OWHTO) may lead to gait alteration, which change the contact loading in the contralateral knee, while clear evidence about the impact on contralateral knee still lacks. The purpose of the current study was to evaluate the change in scintigraphic uptake using SPECT-CT in the medial compartment of the contralateral knee following OWHTO. METHODS: Contralateral radiographic measurements were performed for patients with medial osteoarthritis and varus malalignment of >5° treated with OWHTO in this retrospective analysis. The medial compartmental changes according to SPECT/CT analysis before and 1-year after OWHTO were evaluated on the contralateral side. RESULTS: The study comprised 72 patients. The mean preoperative mechanical femorotibial angle was a mean varus of 7.6° (range, 5.1° - 13.0°), corrected to a mean valgus of 2.5° (range, 1.9° - -8.5°) postoperatively. The average grading of the scintigraphic uptakes in the medial compartment of the contralateral knee was significantly decreased 1 year postoperatively than after the surgery (from 2.8 ± 0.4 to 2.1 ± 0.6, p < 0.001). Measurable differences in varus alignment on radiographs of the contralateral limb were identified. The preoperative mechanical axis value decreased from 8.0° ± 2.4° to 6.7° ± 2.6° at the 3-month postoperative visit (p = 0.011). The overall decrease in varus alignment remained at the 2-year final postoperative follow-up. CONCLUSION: Alignment correction by OWHTO results in reducing scintigraphy uptakes in medial compartment and improvement in mechanical alignment of the contralateral knee. LEVEL OF EVIDENCE: Therapeutic Level IV.

Adrenal ganglioneuroma with nodal metastases on 123I-MIBG SPECT/CT and 18F-FDG PET/CT.

Ganglioneuroma is a well-differentiated tumor originating from neural crest cells of the sympathetic nervous system. Although benign, a few cases have been reported that ganglioneuroma can metastasize to other sites. We report a case of adrenal ganglioneuroma with para-aortic nodal metastases with low FDG and MIBG uptake. In order to avoid unnecessary wide excision or aggressive medication, it is important to consider the possibility of ganglioneuroma preoperatively even if with metastases.

SPECT/CT imaging of poor sleep quality in people with epilepsy.

PURPOSE: To analyze the characteristics of cerebral blood flow changes of poor sleep quality in people with epilepsy(PWE). METHODS: 90 PWE treated in The General Hospital of Ningxia Medical University from December 2021 to September 2023 were divided into poor sleep quality group (PSQG) and good sleep quality group (GSQG) according to the Chinese version of the Pittsburgh Sleep Quality Index (CPSQI), to compare the differences in cerebral perfusion between the two groups of patients, so as to summarize the characteristics of cerebral blood flow changes of poor sleep quality in PWE. RESULTS: The positive rate of interictal single-photon emission computed tomography/computed tomography (SPECT/CT) was 76.7 %(69/90), which showed localized cerebral hypoperfusion. There was no statistical difference between the two groups of PSQG (N=29) and GSQG (N=61) in terms of the positive rate of SPECT/CT, the number of hypoperfusion foci, and the range of hypoperfusion foci. In PSQG and GSQG, 9 patients(31.0 %) and 6 patients(9.8 %) showed hypoperfusion in the right parietal lobe, respectively, and the difference between the two groups was statistically significant (P=0.017). There was no statistical difference the rate of the interictal epileptiform discharges (IEDs) and the brain area of IEDs in electroencephalography(EEG) between the two groups. CONCLUSION: SPECT/CT of poor sleep quality in PWE demonstrated hypoperfusion in the right parietal lobe.

EANM position paper on challenges and opportunities of full-ring 360° CZT bone imaging: it's time to let go of planar whole-body bone imaging.

The introduction of smaller footprint, more sensitive Cadmium-Zinc-Telluride (CZT)-based detectors with improved spatial and energy resolution has enabled the design of innovative full-ring 360° CZT SPECT/CT systems (e.g., VERITON® and StarGuide™). With this transformative technology now aiming to become mainstream in clinical practice, several critical questions need to be addressed. This EANM position paper provides practical recommendations on how to use these devices for routine bone SPECT/CT studies, facilitating the transition from traditional planar whole-body imaging and conventional SPECT/CT to these novel systems. In particular, initial guidance is provided on imaging acquisition and reporting workflows, image reconstruction, and CT acquisition parameters. Given the emerging nature of this technology, the available evidence base is still limited, and the proposed adaptations in workflows and scan protocols will likely evolve before being integrated into definitive guidelines. In the meantime, this EANM position paper serves as a comprehensive guide for integrating these advanced hybrid SPECT/CT imaging systems into clinical practice and outlining areas for further study.

[131I]6ß-Iodomethyl-19-norcholesterol SPECT/CT for the Lateralization of Mineralocorticoid Overproduction in Primary Aldosteronism.

Primary: aldosteronism is a frequent cause of secondary hypertension. With access to specialized care, an increasing number of patients with aldosteronism are being identified. Primary aldosteronism is treatable by adrenal surgery if aldosterone excess originates from one of the two, and not from both, adrenals. Bilateral hyperplasia requires lifelong mineralocorticoid receptor antagonist treatment. Up till now, adrenal venous sampling (AVS) has been widely used to distinguish between one-sided and two-sided aldosterone overproduction and patient selection for surgery. AVS is an invasive technique, and the unsuccessful sampling of the right adrenal vein during AVS often prevents side comparison, making the AVS procedure useless. Molecular imaging using [131I]6ß-iodomethyl-19-norcholesterol with SPECT CT imaging (SPECT/CT) may be a potential alternative. METHODS: In 42 consecutive patients with confirmed primary aldosteronism, molecular imaging has been performed. After dexamethasone suppression of the non-affected adrenal tissue, 37 MBq [131I]6ß-iodomethyl-19-norcholesterol was injected i.v., and SPECT/CT images were taken 7 days later. Based on the visual evaluation of the images by two nuclear medicine specialists, patients with one-sided tracer accumulation underwent adrenalectomy. To identify a SPECT/CT parameter that best characterizes the side difference, the maximum counts and the mean counts of spherical VOIs were analyzed. RESULTS: Of the 42 patients, 24 had one-sided aldosterone overproduction by SPECT/CT. After surgical removal of the involved adrenal, all 24 patients with SPECT/CT-identified unilateral aldosteronism achieved biochemical cure, defined as a normalized potassium level combined with an aldosterone-to-renin ratio ≤ 30. To identify the best measurable parameter of SPECT/CT side difference, the mean counts and maximum counts of a series of spherical VOIs of different diameters were analyzed. The ratio of the mean counts of 3 cm spherical VOIs of the right and left adrenal regions (lateralization index) was the best discriminator; a ratio of ≥1.29 was characteristic of one-sided disease, without overlap between the one-sided and two-sided patient groups. CONCLUSIONS: [131I]6ß-iodomethyl-19-norcholesterol SPECT/CT with a count-based image interpretation and side-ratio calculation may be an equipollent non-invasive substitute for adrenal venous sampling in the lateralization of mineralocorticoid overproduction. It reliably identifies unilateral disease and facilitates patients' selection for surgical intervention. If confirmed by others, this functional imaging may replace AVS when lateralization is required for management decisions in primary aldosteronism.

The [99mTc]Tc-HMPAO-labelled white blood cell SPECT/CT as a novel criterion for infective endocarditis diagnosis.

AIMS: Infective endocarditis (IE) poses a significant clinical challenge, necessitating nuanced diagnostic tools for early and accurate detection. The diagnostic role of the hybrid technique of single-photon emission tomography-computed tomography with technetium-99 m-hexamethylpropyleneamine oxime-labelled leukocytes ([99mTc]Tc-HMPAO-SPECT/CT) has evolved in recent years. This single-center study assessed whether the recent inclusion in the 2023 European Society of Cardiology modified diagnostic criteria of IE (2023 ESC) of infectious lesions detected with [99mTc]Tc-HMPAO-SPECT/CT affects their diagnostic performance. METHODS AND RESULTS: Between 2015 and 2019, we enrolled 205 consecutive adults with suspected IE. All participants underwent [99mTc]Tc-HMPAO-SPECT/CT scans (370-740 MBq). Scans were deemed positive in the presence of intracardiac abnormal tracer uptake and/or within the cardiac implantable electronic device. Patients were prospectively followed-up for 12 ± 10 months. Local device infection (LDI) or IE was diagnosed in 75 (36.6 %) patients, while 72 (35.1 %) [99mTc]Tc-HMPAO-SPECT/CT results returned positive. Moreover, extracardiac infectious foci were detected in 25 % of [99mTc]Tc-HMPAO-SPECT/CT scans. The inclusion of both intracardiac and extracardiac lesions detected with [99mTc]Tc-HMPAO-SPECT/CT yields significantly higher sensitivity (p = 0.003) and negative predictive value (NPV) (p = 0.009). CONCLUSION: The inclusion of [99mTc]Tc-HMPAO-SPECT/CT into the IE diagnostic work-up improves the appropriate classification of patients. For patients with IE, the extended inclusion of lesions detected with [99mTc]Tc-HMPAO-SPECT/CT in the ESC 2023 diagnostic criteria significantly improves sensitivity and NPV while reducing potential IE misdiagnoses. This pioneering imaging modality is poised to become an integral component of clinical practice, promising to advance IE diagnosis and management.

Association between 99mTc-PSMA SPECT/CT imaging and prostate-specific antigen (PSA) and alkaline phosphatase (ALP) levels post-endocrine therapy in patients with prostate cancer and bone metastases.

AIM: To investigate the association between positive lesions detected by 99mTc-PSMA SPECT/CT and blood levels of prostate-specific antigen (PSA) and alkaline phosphatase (ALP) in patients with prostate cancer (PCa) and bone metastasis undergoing endocrine therapy. METHODS: A retrospective analysis was performed on 43 patients diagnosed with PCa bone metastasis who underwent endocrine therapy. PSA, ALP, whole body bone imaging and 99mTc-PSMA SPECT/CT imaging were collected from all patients (Among them, 17 cases were re-examined 99mTc-PSMA SPECT/CT imaging). According to the results of the first 99mTc-PSMA SPECT/CT imaging for detecting bone metastasis, all cases were divided into two groups: positive group and negative group. The relationship between 99mTc-PSMA imaging and PSA and ALP was analyzed by ROC curve. Fisher exact probability method was used to examine the changes in imaging radioactivity uptake, PSA, and ALP levels in 17 patients after treatment, and P < 0.05 was statistically significant. RESULTS: All 43 patients had different degrees of radioactive concentrations on whole-body bone imaging. The first 99mTc-PSMA SPECT/CT imaging showed positive bone metastases in 31 cases and negative bone metastases in 12 cases. ROC curve analysis of PSA and ALP, AUC were 0.778 and 0.770, respectively. When PSA > 1.13 ng/mL, 99mTc-PSMA SPECT/CT imaging diagnostic sensitivity was 93.55%, and specificity was 66.67%. When ALP was >86U/L, the diagnostic sensitivity of 99mTc-PSMA SPECT/CT imaging was 64.52%, and the specificity was 83.33%. In 17 cases, the PSA level decreased in 7 and increased in 10. There were 10 cases of increased ALP and 7 cases of decreased ALP levels. In the second 99mTc-PSMA imaging lesion, there were 9 cases with decreased or no uptake, and 8 cases with increased uptake or number of lesions. The changes in 99mTc-PSMA uptake by Fisher's exact probability method were statistically significant (P < 0.05, P = 0.006, and P = 0.006, respectively), and ALP level was not statistically significant (P = 0.563). CONCLUSION: 99mTc-PSMA SPECT/CT imaging can detect PCa bone metastases, which are related to PSA levels. When PSA > 1.13 ng/mL, the sensitivity of diagnosis and detection of positive bone metastases is higher, and when ALP is >86U/L, 99mTc-PSMA imaging has higher specificity.

In Vivo Detection of Multidrug-Resistance Related Proteins in Locally Advanced Breast Cancer Using 99mTc-MIBI SPECT/CT Imaging: Correlation with Clinical Outcomes.

OBJECTIVE: Neoadjuvant chemotherapy (NACT) is widely used for treating locally advanced Breast cancer (LABC). However, development of multidrug resistance (MDR) is the main underlying factor for chemoresistance. Technetium-99m methoxyisobutylisonitrile (99mTc-MIBI) is a substrate for MDR. This study aimed to analyze the relationship between expression of MDR-related proteins (P-gp and Bcl-2) and 99mTc-MIBI uptake and retention in BC tumor cells, pathologic response to NACT, disease free survival (DFS) and overall survival (OS). METHODS: prospective analysis recruited 31 patients with LABC who received NACT between January 2019 and March 2020. 99mTc-MIBI planar and SPECT/CT imaging was conducted before and after NACT. Qualitative and quantitative analyses were performed, pre and post-NACT early and delayed lesion to non-lesion (LNL) ratios, and retention index (RI) of 99mTc-MIBI were calculated. Expression of P-gp and Bcl-2 in tumor cells was determined by immunohistochemistry. RESULTS: Quantitively, inter-reader ICC for SPECT/CT based quantification was consistently higher than that of planar images. Post-NACT LNL ratios were significantly higher in patients with pathologic persistent disease (PPD). A change in RI between pre- and post-NACT scans demonstrated a significant association with DFS with a hazard ratio of 0.7 (95%CI: 06-1.0). Qualitatively, SPECT/CT was significantly more accurate compared to planar imaging in identifying residual viable tumor (81% compared to 57%).  Her2neu positivity and high post-operative Bcl-2 and P-gp were associated with worse DFS. A significant association was found between increased expression of post-NACT Bcl-2 and PPD, advanced tumor stage and poor OS. CONCLUSION: 99mTc-MIBI SPECT/CT based qualitative evaluation of BC response to NACT is more accurate than planar imaging. Post-NACT MIBI retention is positively correlated with P-gp and Bcl-2 expression. 99mTc-MIBI SPECT/CT may predict MDR development. High post-NACT Bcl-2 expression is significantly associated with advanced tumor stage and OS. High post-NACT P-gp expression has a worse impact on pathologic response and DFS.

Imaging in Renal Cell Carcinoma Detection.

INTRODUCTION: Imaging in renal cell carcinoma (RCC) is a constantly evolving landscape. The incidence of RCC has been rising over the years with the improvement in image quality and sensitivity in imaging modalities resulting in "incidentalomas" being detected. We aim to explore the latest advances in imaging for RCC. METHODS: A literature search was conducted using Medline and Google Scholar, up to May 2024. For each subsection of the manuscript, a separate search was performed using a combination of the following key terms "renal cell carcinoma", "renal mass", "ultrasound", "computed tomography", "magnetic resonance imaging", "18F-Fluorodeoxyglucose PET/CT", "prostate-specific membrane antigen PET/CT", "technetium-99m sestamibi SPECT/CT", "carbonic anhydrase IX", "girentuximab", and "radiomics". Studies that were not in English were excluded. The reference lists of selected manuscripts were checked manually for eligible articles. RESULTS: The main imaging modalities for RCC currently are ultrasound, computed tomography (CT) and magnetic resonance imaging (MRI). Contrast-enhanced US (CEUS) has emerged as an alternative to CT or MRI for the characterisation of renal masses. Furthermore, there has been significant research in molecular imaging in recent years, including FDG PET, PSMA PET/CT, 99mTc-Sestamibi, and anti-carbonic anhydrase IX monoclonal antibodies/peptides. Radiomics and the use of AI in radiology is a growing area of interest. CONCLUSIONS: There will be significant change in the field of imaging in RCC as molecular imaging becomes increasingly popular, which reflects a shift in management to a more conservative approach, especially for small renal masses (SRMs). There is the hope that the improvement in imaging will result in less unnecessary invasive surgeries or biopsies being performed for benign or indolent renal lesions.

The Role of Risk Factors for the Progression of Patients with T1b-T2 Papillary Thyroid Carcinoma (PC) during Long-Term Follow-Up.

Background/Objectives: Recurrence prediction for patients with PC and tumor sizes ranging between 1 and 4 cm, classified as T1b and T2, remains a controversial problem. We evaluated which risk factors, identified during the primary tumor surgery, might play a prognostic role in predicting disease progression. Methods: We retrospectively enrolled 363 patients with classic PC who were in follow-up (207 T1b, 156 T2), with tissue risk factors at surgery in 209/363 cases. In all cases, an 131I-whole-body scan, SPECT/CT, and US were employed to detect any metastases during follow-up, and histology was used to confirm lesions. In the absence of surgery, metastases were validated by radioisotopic and radiologic procedures, eventually culminating in a needle biopsy and sequential thyroglobulin changes. Results: Metastases occurred in 61/363 (16.8%) patients (24 T1b, 37 T2). In 50/61 cases, the following risk factors were identified: minimal extrathyroid tumor extension (mETE) alone in 12/50 patients, neck lymph node (LN) metastases in 8/50 cases, and multifocality/multicentricity (M/M) in 6/50 cases. In the remaining 24/50 cases, the risk factors were associated with each other. From a Cox regression multivariate analysis, metastasis development was significantly (p < 0.001) influenced by only mETE and LN metastases, with a shorter disease-free survival (log-rank test). Conclusions: The current study proves that mETE and neck LN metastases are associated with aggressive PC. While LN metastasis' role is known, mETE's role is still being debated, and was removed by the AJCC's eighth edition because it was considered to not be associated with an unfavorable prognosis. However, this interpretation is not supported by the present study and, according to comparable studies, we suggest a revision of the mETE classification be considered in the next AJCC edition.

Quantitative SPECT/CT Metrics in Early Prediction of [177Lu]Lu-DOTATATE Treatment Response in Gastroenteropancreatic Neuroendocrine Tumor Patients.

Our objective is to explore quantitative imaging markers for early prediction of treatment response in patients with gastroenteropancreatic neuroendocrine tumors (GEP-NETs) undergoing [177Lu]Lu-DOTATATE therapy. By doing so, we aim to enable timely switching to more effective therapies in order to prevent time-resource waste and minimize toxicities. Methods: Patients diagnosed with unresectable or metastatic, progressive, well-differentiated, receptor-positive GEP-NETs who received 4 sessions of [177Lu]Lu-DOTATATE were retrospectively selected. Using SPECT/CT images taken at the end of treatment sessions, we counted all visible tumors and measured their largest diameters to calculate the tumor burden score (TBS). Up to 4 target lesions were selected and semiautomatically segmented. Target lesion peak counts and spleen peak counts were measured, and normalized peak counts were calculated. Changes in TBS (ΔTBS) and changes in normalized peak count (ΔnPC) throughout treatment sessions in relation to the first treatment session were calculated. Treatment responses were evaluated using third-month CT and were binarized as progressive disease (PD) or non-PD. Results: Twenty-seven patients were included (7 PD, 20 non-PD). Significant differences were observed in ΔTBSsecond-first, ΔTBSthird-first, and ΔTBSfourth-first (where second-first, third-first, and fourth-first denote scan number between the second and first, third and first, and fourth and first [177Lu]Lu-DOTATATE treatment cycles), respectively) between the PD and non-PD groups (median, 0.043 vs. -0.049, 0.08 vs. -0.116, and 0.109 vs. -0.123 [P = 0.023, P = 0.002, and P < 0.001], respectively). ΔnPCsecond-first showed significant group differences (mean, -0.107 vs. -0.282; P = 0.033); ΔnPCthird-first and ΔnPCfourth-first did not reach statistical significance (mean, -0.122 vs. -0.312 and -0.183 vs. -0.405 [P = 0.117 and 0.067], respectively). At the optimal threshold, ΔTBSfourth-first exhibited an area under the curve (AUC) of 0.957, achieving 100% sensitivity and 80% specificity. ΔTBSsecond-first and ΔTBSthird-first reached AUCs of 0.793 and 0.893, sensitivities of 71.4%, and specificities of 85% and 95%, respectively. ΔnPCsecond-first, ΔnPCthird-first, and ΔnPCfourth-first showed AUCs of 0.764, 0.693, and 0.679; sensitivities of 71.4%, 71.4%, and 100%; and specificities of 75%, 70%, and 35%, respectively. Conclusion: ΔTBS and ΔnPC can predict [177Lu]Lu-DOTATATE response by the second treatment session.

A prospective study to compare the diagnostic accuracy of 99mTc-CNDG SPECT/CT and contrast-enhanced CT in staging of non-small cell lung cancer.

OBJECTIVE: To explore the value of 99mTc-isonitrile deoxyglucosamine (CNDG) SPECT/CT in the staging and resectability diagnosis of non-small cell lung cancer (NSCLC) compared with contrast-enhanced CT (CECT). METHODS: This research was approved by the hospital ethics review committee. Sixty-three patients with NSCLC received 99mTc-CNDG SPECT/CT, CECT and initial TNM staging before treatment. Thirty-three patients who underwent radical surgery underwent postoperative pathological TNM staging as the reference standard. Another thirty patients underwent radiochemotherapy; among them, the reference standard of 7 patients of N staging and 5 patients of M staging was based on biopsy pathology, and the diagnosis of the remaining lesions was confirmed by at least one different image or clinical imaging follow-up for more than 3 months. The McNemar test and receiver operating characteristic (ROC) curve analysis were used to compare the diagnostic accuracy of staging and resectability of 99mTc-CNDG SPECT/CT and CECT in NSCLC, respectively. RESULTS: For all patients and surgical patients, the accuracies of 99mTc-CNDG SPECT/CT in diagnosing the T stage and N stage were higher than those of CECT (all patients: 90.5%, 88.9% vs. 79.4%, 60.3%; surgical patients: 81.8%, 78.8% vs. 60.6%, 51.5%), and the differences were statistically significant (all patients: T stage, P = 0.016; N stage, P = 0.000; surgical patients: T stage, P = 0.016; N stage, P = 0.004). For all patients, the accuracy of 99mTc-CNDG SPECT/CT in diagnosing the M stage was higher than that of CECT (96.8% vs. 90.5%), but the difference was not statistically significant (P = 0.289). ROC curve analysis showed that the accuracy of 99mTc-CNDG SPECT/CT in diagnosing the potential resectability of NSCLC was significantly better than that of CECT (P = 0.046). CONCLUSION: This preliminary clinical study shows that 99mTc-CNDG SPECT/CT is of great value for accurate clinical staging of NSCLC compared with CECT and can significantly improve the accuracy of resectability diagnosis.

A general perspective for the conduct of radiolabelled distribution, metabolism, and excretion studies for antibody-drug conjugates.

Antibody-drug conjugates (ADCs) are a class of biopharmaceuticals that combine the specificity of monoclonal antibodies (mAbs) with the cytotoxicity of small molecule drugs. 15 ADCs have been approved by regulatory authorities up to now, mainly for indications in oncology, however, this review paper will only focus on the 13 ADCs that have been approved by either the FDA or EMA.ADME (Absorption, Distribution, Metabolism, and Excretion) studies are essential for the development of small molecule drugs to evaluate their disposition properties. These studies help to select drug candidates, determine the optimal dosing regimen and help to identify potential safety concerns for the drug of interest in human. Tissue distribution studies are also important as they facilitate the understanding of the efficacy and safety for parent drug and its metabolites in preclinical and clinical studies.For biologics, ADME studies are usually not required. In this paper, we review the existing approval packages and literature for approved ADCs to determine the extent of ADME studies performed as part of ADC registration packages.We conclude that ADME studies are recommended for the development of ADCs if new linkers and payloads are used that have never been used in humans before as these studies provide valuable information on the pharmacokinetic properties, optimal dosing regimen, and potential safety concerns. However, for the development of ADCs with established linker payload combinations, radiolabelled ADME studies may not be necessary if the distribution, metabolism and excretion properties have been described before. Clinical radiolabelled ADME studies are not recommended where patients are treated for life threating diseases like for indications in oncology.

Prospective Study Comparing [99mTc]Tc-DP-FAPI Quantitative SPECT/CT with [68Ga]Ga-FAPI-04 PET/CT in Patients with Gastrointestinal Tumors.

Over the past decade, [68Ga]Ga-FAPI-04 positron emission tomography (PET)/CT imaging has been widely used for the treatment of various tumors. However, the application of 99mTC-labeled fibroblast activation protein inhibitors in tumors has been less studied. Our team previously demonstrated the safe biological distribution of [99mTc]Tc-DP-FAPI in the human body. Based on this, this study reports the accuracy of [99mTc]Tc-DP-FAPI in the imaging diagnosis of gastrointestinal tumors and compares it with that of [68Ga]Ga-FAPI-04 to evaluate the differences. A total of 24 patients with clinically diagnosed gastrointestinal tumors were prospectively included. All patients received [99mTc]Tc-DP-FAPI quantitative SPECT/CT imaging on the first day and [68Ga]Ga-FAPI-04 PET/CT imaging on the second day. And the effectiveness of the two imaging probes in detecting suspicious lesions was analyzed and compared. The primary tumors of all 24 patients were well detected by two imaging probes, and the sensitivity of [99mTc]Tc-DP-FAPI and [68Ga]Ga-FAPI-04 to the primary lesions was 100%. [99mTc]Tc-DP-FAPI examined 21 lymph nodes with a sensitivity and specificity of 32.8% and 10.9%, and [68Ga]Ga-FAPI-04 detected 57 lymph nodes with a sensitivity and specificity of 89.1% and 67.2%, respectively. Three distant metastases were detected by [99mTc]Tc-DP-FAPI and nine metastases by [68Ga]Ga-FAPI-04. The study showed that [99mTc]Tc-DP-FAPI is highly sensitive to detecting primary lesions of gastrointestinal tumors. Compared with [68Ga]Ga-FAPI-04, [99mTc]Tc-DP-FAPI has the same sensitivity in detecting primary tumors but has certain limitations in detecting metastases. [99mTc]Tc-DP-FAPI is of great value for preliminary screening of tumor lesions and early diagnosis of disease in patients who are suspected of having gastrointestinal tumors.

Peritoneal scintigraphy and SPECT/TC in the diagnosis of leaks in patients on peritoneal dialysis.

OBJECTIVE: To assess the usefulness of peritoneal cavity scintigraphy and the contribution of SPECT/CT in patients on peritoneal dialysis with suspected leak. METHODOLOGY: An observational case series study is carried out. It consists of a longitudinal, retrospective and descriptive study. 11 patients on peritoneal dialysis were studied and it was realiced a peritoneal cavity scintigraphy test and SPECT/CT to evaluate a peritoneal leak. RESULTS: In 54,5% of the patients, a positive study of peritoneal leak was obtained. The most frequent localitations were in the abdominal wall at the catheter entry level and the inguinal hernia. In the cases with sintomatology like pain and celullitis of the subcutaneous tract of the cateter the frequent of leak was 100%. There was a change in therapeutic management in patients with a positive study. There was not relevant changes in initial dialysis regimen in patients with a negative study. In this cases, except for one patient who required hemodialysis, all patients experienced clinical improvement. CONCLUSIONS: Peritoneal scintigraphy and SPECT/CT study are non-invasive techniques that allow an adequate diagnosis and subsequent management of peritoneal leak.

Radioimaging Foam Cells Infiltrating Atherosclerotic Plaques in Mice Using 125I-labeled oxLDL as a Radiotracer.

Bioimaging such as magnetic resonance is used to monitor atherosclerotic plaques consisting of foam cells, which are derived from macrophages that have ingested oxidized low-density lipoprotein (oxLDL). However, the current bioimaging techniques are not highly specific and sensitive in detecting foam cells, calling for the development of higher precision foam cell detection probes. Here, we investigated the utility of iodine-125-labeled oxLDL (125I-oxLDL) as a prototype radiotracer in the radioimaging of foam cells infiltrating atherosclerotic plaques. Mouse bone marrow-derived macrophages (BMDMs) were used to analyze oxLDL uptake. Atherosclerosis mouse model was injected with 125I-oxLDL and DiI-labeled oxLDL (DiI-oxLDL). Accumulation of 125I-oxLDL and DiI-oxLDL in foam cells infiltrating atherosclerotic plaques was examined using Oil Red O (ORO) staining, autoradiography, and fluorescent immunohistochemistry. BMDMs phagocytosed oxLDL/125I-oxLDL via CD36, but not LDL/125I-LDL. The radioactive signal from 125I-oxLDL phagocytosed by the BMDMs could be detected for at least 3 days. In atherosclerosis mouse model, atherosclerotic plaques formed in the aortic arches and valves. The radioactive signal of the injected 125I-oxLDL was detected in atherosclerotic plaques of the aortic arch, and its intensity was positively correlated with the lesion size. Furthermore, the DiI-oxLDL fluorescent signals were detected in foam cells accumulating in atherosclerotic plaques. Thus, we found that 125I-oxLDL can be used as a radiotracer in the radioimaging of foam cells in atherosclerotic plaques by autoradiography, suggesting its potential future applications in bioimaging methods such as single-photon emission computed tomography.

The impact of different reconstruction parameters on quantitative 99mTc-DPD SPECT/CT values in the assessment of cardiac transthyretin amyloidosis.

AIM: To assess in a phantom and in a clinical study the influence of different reconstruction parameters on quantitative SPECT/CT values in the assessment of cardiac transthyretin amyloidosis (ATTR-CA). METHOD: A hybrid SPECT/CT camera with a proprietary software for SPECT/CT-based quantification of myocardial uptake of 99mTc-DPD was used. Images were reconstructed with 6 different protocols, differing in iterations, subset and Gaussian filter. Quantitative values were tested in phantom and clinical studies across different reconstruction protocols. Values were automatically calculated both as kBq/ml and as maximum, mean and peak standardized uptake value (SUV). RESULTS: The standard parameters provided by the manufacturer (reconstruction 1) yielded higher accuracy in quantifying, with measuring 97.1% of the expected activity in the phantom. Reconstructions with higher Gaussian filter caused a systematic underestimation of quantified values of 27.2% (p < 0.01). Results were replicated in the clinical study consisting of 155 patients with suspected ATTR-CA, wherein changing the number of iterations and subsets was not associated with a statistically significant difference in quantitative values compared to reconstruction 1, while a higher Gaussian filter caused inaccurate quantification with up to 24% of difference measured. CONCLUSION: Different reconstruction parameters can impact quantitative values on 99mTc-DPD SPECT/CT. Therefore, parameters should be maintained consistently across different acquisitions and different centres.

Complicated Inguinal Hernia Incidentally Detected on a Radiolabelled Autologous White Blood Cell Scan.

A 73-year-old male with left hip prosthesis infection performed a 99mTc HMPAO-labelled autologous WBC (WBC) scan to evaluate the response to antibiotic therapy. Since the early planar scan, an area of increased activity was visible extending from the left groin region to the ipsilateral flank. At late planar images, the area progressively focused in the left groin, site of a painful inguinal hernia. The contextual tomographic acquisition showed increased activity partly referable to non-specific intestinal contents and partly localized at the parietal wall of the herniated intestinal loop. Our case suggests that the incidental detection of increased accumulation of WBC in correspondence of the intestinal wall of an inguinal hernia may indicate inflammatory involvement and subsequent further complications.