Revista Espanola De Medicina Nuclear E Imagen Molecular最新文献

Objective

The aim of the study was evaluate the diagnostic performance of [⁶⁸Ga]Ga-DOTA-TOC and [¹⁸F]FDG PET/CT in patients with histologically proven neuroendocrine tumors (NETs), as well as the correlation of the visualized findings with the tumor grade.

Material and methods

We included 50 patients with NETs who underwent both [⁶⁸Ga]Ga-DOTA-TOC and [¹⁸F]FDG PET/TC. The pooled sensitivity of both scans was compared, as well as [⁶⁸Ga]Ga-DOTA-TOC and [¹⁸F]FDG for each tumor grade (grade 1 [G1], grade 2 [G2] and grade 3 [G3]). Also, the sensitivity of [⁶⁸Ga]Ga-DOTA-TOC and [¹⁸F]FDG as a function of the continuous variable Ki-67 was investigated. Finally, the number of lesions detected by both PET radiopharmaceuticals for each tumor grade was compared.

Results

The pooled sensitivity of both PET/CT (96%) was higher than [⁶⁸Ga]Ga-DOTA-TOC (84%) and [¹⁸F]FDG (44%) separately, with statistically significant differences. The sensitivity of [⁶⁸Ga]Ga-DOTA-TOC was higher than [¹⁸F]FDG in both G1 (P = .004) and G2 (P < .001). In G3 the performance of both scans detected disease in 100% of this subgroup. The sensitivity of [⁶⁸Ga]Ga-DOTA-TOC and [¹⁸F]FDG PET/CT correlated significantly with the Ki-67 proliferative index. In G2 patients the number of lesions detected with [⁶⁸Ga]Ga-DOTA-TOC was higher than [¹⁸F]FDG.

Conclusions

The performance of both PET/CT, particularly in G2 and G3, demonstrates the molecular heterogeneity of metastatic NETs and contributes to the selection of a more appropriate treatment, particularly in those high-grade patients who may benefit from radionuclide therapy (PRRT).

Objective

The aim of our study was to evaluate the contribution of ¹⁸Fluorine-fluorodeoxyglucose positron emission tomography (18F-FDG PET) radiomic data obtained from both the tumoral and peritumoral area in predicting pathological complete response (pCR) in patients with locally advanced breast cancer receiving neoadjuvant chemotherapy (NAC).

Methods

Female patients with a diagnosis of invasive ductal carcinoma who received NAC were evaluated retrospectively. The volume of interest (VOI) of the primary tumor (VOI-_T) was manually segmented, then a voxel-thick VOI was added around VOI-_T to define the peritumoral area (VOI-_PT). Morphological, intensity-based, histogram and texture parameters were obtained from VOIs. The patients were divided into two groups as pCR and non-complete pathological response (npCR). A «radiomic model» was created with only radiomic features, and a «patho-radiomic model» was created using radiomic features and immunohistochemical data.

Results

Of the 66 patients included in the study, 21 were in the pCR group. The only statistically significant feature from the primary tumor among patients with pCR and npCR was Morphological_Compacity-_T (AUC: 0.666). Between response groups, a significant difference was detected in 2 morphological, 1 intensity, 4 texture features from VOI-_PT; no correlation was found between Morphological_Compacity-_PT and NGLDM_contrast-_PT. The obtained radiomic model's sensitivity and accuracy values were calculated as 61.9% and 75.8%, respectively (AUC: 0.786). When HER2 status was added, sensitivity and accuracy values of the patho-radiomic model increased to 85.7% and 81.8%, respectively (AUC: 0.903).

Conclusions

Evaluation of PET peritumoral radiomic features together with the primary tumor, rather than just the primary tumor, provides a better prediction of the pCR to NAC in patients with breast cancer.

Background and objectives

In a hospital radiopharmacy with 2a operational level, including the preparation of radiopharmaceuticals from prepared and approved reagent kits, it is common to have a single activimeter or dose calibrator for labeling and fractionation, and to perform the quality controls of the ^99mTc-radiopharmaceuticals. In certain cases, the accumulation of radioactive material or accidental contamination of the work area causes the background to exceed the limits to carry out the radiochemical purity analyses and it is necessary to look for viable alternatives. In this work, a Geiger Müller detector (equipped with a probe for measuring surface contamination) frequently used for radioprotection purposes, was validated as an alternative and its performance was compared against the activimeter for ^99mTc-radiopharmaceuticals.

Materials and methods

Using [^99mTc]pertechnetate, systematic studies of error analyses and detector response to activity concentration, activity and measurement time were carried out in liquid matrices and in paper. The results were compared against an activimeter calibrated for [^99mTc]Tc.

Results

The developed method was used to determine the radiochemical purity of the compounds [^99mTc]Tc-MDP and [^99mTc]Tc-MIBI by ascending paper chromatography tests, obtaining comparable values to those measured with an activimeter in the same system (within 1% uncertainty) and using the method of vial partitioning in a dedicated equipment.

Conclusions

This work demonstrates that a Geiger Müller detector with a probe for measuring surface contamination can be adequately used to replace other equipment in the control of radiochemical purity in the hospital radiopharmacy.

Introduction and objectives

Lung cancer is the second type of cancer with the second highest incidence rate and the first with the highest mortality rate in the world. Machine learning through the analysis of imaging tests such as positron emission tomography/computed tomography (PET/CT) has become a fundamental tool for the early and accurate detection of cancer. The objective of this study was to propose an image analysis architecture (PET/CT) ordered in phases through the application of ensemble or combined machine learning methods for the early detection of lung cancer by analyzing PET/CT images.

Material and methods

A retrospective observational study was conducted utilizing a public dataset titled «A large-scale CT and PET/CT dataset for lung cancer diagnosis.» Various imaging modalities, including CT, PET, and fused PET/CT images, were employed. The architecture or framework of this study comprised the following phases: 1. image loading or collection; 2. image selection; 3. image transformation, and 4. balancing the frequency distribution of image classes. Predictive models for lung cancer detection using PET/CT images included: a) the Stacking model, which used Random Forest and Support Vector Machine (SVM) as base models and complemented them with a Logistic Regression model, and b) the Boosting model, which employed the Adaptive Boosting (AdaBoost) model for comparison with the Stacking model. Quality metrics used for evaluation included accuracy, precision, recall, and F1-score.

Results

This study showed a general performance of 94% with the Stacking method and a general performance of 77% with the Boosting method.

Conclusions

The Stacking method proved to be a model with high performance and quality for lung cancer detection when analyzing PET/CT images.

Objective

To compare the usefulness of MRI and PET/CT in nodal staging (N) of patients with locally advanced rectal cancer (LARC).

Material and methods

Retrospective study of patients with LARC, who completed their initial staging with PET/CT, between January 2020 and March 2023. Regional nodes were assessed, and N was determined using both techniques according to TNM criteria. Concordance between MRI and PET/CT was analyzed. The accuracy of both techniques was calculated for those patients who underwent direct surgery. Non-regional pelvic lymph nodes were evaluated by both modalities.

Results

Among the 73 patients, 48 were ultimately diagnosed with a locally advanced stage. Of these, 39 underwent neoadjuvant treatment (chemoradiotherapy) followed by surgery, and 9 direct surgery. In 25, the PET/CT extension study revealed distant disease, leading to systemic treatment. Weak concordance was observed between MRI and PET/CT in determining N (k = 0.286; P < .005). Out of 73 patients, 31 (42%) exhibited concordance, and 42 (58%) showed discordance. In 83% of the discordant cases, MRI overstaged compared to PET/CT, with 17 cases indicating nodal involvement (N+) by MRI and N0 by PET/CT. Diagnostic accuracy was 78% for both techniques. Sensitivity, specificity, positive predictive value, and negative predictive value were 80%, 75%, 80%, and 75% for MRI, and 60%, 100%, 100%, and 67%, for PET/CT. PET/CT identified pelvic metastatic adenopathies in 8 patients that were not visible/doubtful by MRI.

Conclusions

In the initial nodal staging of rectal cancer MRI overstages relative to PET/CT. Both modalities are complementary, PET/CT offers higher specificity and MRI higher sensitivity.

Neoplasms are composed of malignant tumour cells, which are surrounded by other non-tumour cellular elements, what has been defined as the microenvironment or tumour stroma. Evidence on the importance of the tumour microenvironment has not stopped growing in recent years. It plays a central role for cell proliferation, tissue invasion, angiogenesis and cell migration.

The paradigm is the family of new FAPI radiopharmaceuticals that show us the density of the fibroblast activation protein (FAP) that is overexpressed in the cell membrane of activated cancer-associated fibroblasts (CAF), and its presence is related to poor prognosis.

The paradigm is the family of new FAPI radiopharmaceuticals, which represents the density of activated fibroblasts associated with cancer. This educational document includes the procedure for performing PET/CT FAPI, biodistribution and the main potentially clinical applications in oncology to date.