18F-FDG PET/CT in Local Ablative Therapies: A Systematic Review

Pathological complete response with immunotherapy and brachytherapy to 15 metastatic liver lesions in a single patient

Materials & methods:

High dose rate interstitial brachytherapy (HDR-IBT) treatment plan for 15 metastatic liver lesions in a patient with pancreatic cancer was retrieved and analyzed for liver dose parameters and diaphragm dose. Serial ¹⁸F-FDG PET-CT scans were reviewed for disease response assessment and left liver lobe volume. Serial laboratory records were analyzed for liver parameters.

Results:

Left liver lobe volume increased from 241 cm³ pre-HDR-IBT to estimated 600 cm³ after seven sessions of HDR-IBT. Metabolic complete response (CR) and subsequently pathological CR was confirmed in the right hepatotectomy specimen for all the 15 PET-CT avid lesions treated with HDR-IBT. Maximum diaphragm dose in a single fraction was 82 Gy. The liver parameters were stable and patient did not develop radiation induced liver disease.

Discussion:

This is the largest reported series of HDR-IBT to liver lesions in a single patient. This first ever reported combined treatment of immunotherapy (IT) and HDR-IBT had likely rendered this patient disease free both at local the liver and systemically. Metabolic CR by PET-CT can be seen as early as 46 days after HDR-IBT. Diaphragm can tolerate very high doses of radiation and repeated treatment.

Conclusion:

In this patient HDR-IBT for multiple liver lesions with IT is well tolerated. PET-CT can be used for response assessment of HDR-IBT liver. Synergistic effect of IT with HDR-IBT and it’s role as bridging for liver resection has clinical potential and should be further studied in prospective trials.

Clinical practice guidelines on image-guided thermal ablation of primary and metastatic lung tumors (2022 edition)

The main contents of the Clinical Practice Guidelines on Image-Guided Thermal Ablation (IGTA) of Primary and Metastatic Lung Tumors (2022 Edition) include the following: epidemiology of primary and metastatic lung tumors; the concepts of the IGTA and common technical features; procedures, indications, contraindications, outcomes evaluation, and related complications of IGTA on primary and metastatic lung tumors; and limitations and future development.

Near-Infrared Photoimmunotherapy for Thoracic Cancers: A Translational Perspective

The conventional treatment of thoracic tumors includes surgery, anticancer drugs, radiation, and cancer immunotherapy. Light therapy for thoracic tumors has long been used as an alternative; conventional light therapy also called photodynamic therapy (PDT) has been used mainly for early-stage lung cancer. Recently, near-infrared photoimmunotherapy (NIR-PIT), which is a completely different concept from conventional PDT, has been developed and approved in Japan for the treatment of recurrent and previously treated head and neck cancer because of its specificity and effectiveness. NIR-PIT can apply to any target by changing to different antigens. In recent years, it has become clear that various specific and promising targets are highly expressed in thoracic tumors. In combination with these various specific targets, NIR-PIT is expected to be an ideal therapeutic approach for thoracic tumors. Additionally, techniques are being developed to further develop NIR-PIT for clinical practice. In this review, NIR-PIT is introduced, and its potential therapeutic applications for thoracic cancers are described.

The Value of 18F-FDG-PET-CT Imaging in Treatment Evaluation of Colorectal Liver Metastases: A Systematic Review

(1) Background: Up to 50% of patients with colorectal cancer either have synchronous colorectal liver metastases (CRLM) or develop CRLM over the course of their disease. Surgery and thermal ablation are the most common local treatment options of choice. Despite development and improvement in local treatment options, (local) recurrence remains a significant clinical problem. Many different imaging modalities can be used in the follow-up after treatment of CRLM, lacking evidence-based international consensus on the modality of choice. In this systematic review, we evaluated ¹⁸F-FDG-PET-CT performance after surgical resection, thermal ablation, radioembolization, and neoadjuvant and palliative chemotherapy based on current published literature. (2) Methods: A systematic literature search was performed on the PubMed database. (3) Results: A total of 31 original articles were included in the analysis. Only one suitable study was found describing the role of ¹⁸F-FDG-PET-CT after surgery, which makes it hard to draw a firm conclusion. ¹⁸F-FDG-PET-CT showed to be of additional value in the follow-up after thermal ablation, palliative chemotherapy, and radioembolization. ¹⁸F-FDG-PET-CT was found to be a poor to moderate predictor of pathologic response after neoadjuvant chemotherapy. (4) Conclusions: ¹⁸F-FDG-PET-CT is superior to conventional morphological imaging modalities in the early detection of residual disease after thermal ablation and in the treatment evaluation and prediction of prognosis during palliative chemotherapy and after radioembolization, and ¹⁸F-FDG-PET-CT could be considered in selected cases after neoadjuvant chemotherapy and surgical resection.

Imaging modalities for monitoring acute therapeutic effects after near-infrared photoimmunotherapy in vivo

Near-infrared photoimmunotherapy (NIR-PIT) induces immediate cell death after irradiation with near-infrared (NIR) light. Acute therapeutic effects caused by NIR-PIT before the change of tumor size is essential to be monitored by imaging modalities. We summarized and compared the imaging modalities for evaluating acute therapeutic effects after NIR-PIT, and aimed to provide a better understanding of advantages and disadvantages of each modality for evaluation in clinical applications. Fluorescence imaging and fluorescence lifetime, with high resolution, remains high accumulation of fluorescence dyes in the normal organs. High resolution and noninvasiveness are the major advantages of magnetic resonance imaging, while ¹⁸ F-fluorodeoxyglucose positron emission tomography provides information about the glucose metabolism. Optical coherence tomography provided more information about the blood vessels. Thus, all of the imaging modalities play an important role in evaluating acute therapeutic effects after NIR-PIT. Clinicians should choose suitable modality according to specific purpose and conditions in clinical application.

A tumor-penetrable drug nanococktail made from human histones for interventional nucleus-targeted chemophotothermal therapy of drug-resistant tumors

Nanoparticle-based chemophotothermal therapy (CPT) is a promising treatment for multidrug resistant tumors. In this study, a drug nanococktail of DIR825@histone was developed by employing doxorubicin (DOX), NIR dye IR825 and human histones for interventional nucleus-targeted CPT of multidrug resistant tumors with an interventional laser. After localized intervention, DIR825@histone penetrated tumor tissues by transcytosis, efficiently entered tumor cells and targeted the cell nuclei. DIR825@histone also exhibited good photothermal performance and thermal-triggered drug release. Efficient multidrug resistant tumor inhibition was achieved by enhanced CPT sensitization and MDR reversion via nuclear targeting. Moreover, an interventional laser assisted DIR825@histone in inhibiting multidrug resistant tumors by promoting the sufficient delivery of laser energy inside the tumor while reducing skin injury. Therefore, DIR825@histone together with this interventional nucleus-targeted CPT strategy holds great promise for treating multidrug resistant tumors.

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Proposing an interventional nucleus-targeted chemophotothermal therapy (CPT) for treating MDR tumors

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Using natural human histones for the first time to fabricate nucleus-targeted nanococktails.

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The nanococktail can penetrate tumor tissues by transcytosis, efficiently enter tumor cells and target the cell nuclei.

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Highly improved intracellular MDR reversion and less heat shock response in drug-resistant tumor cells can be achieved by nucleus-targeted chemophotothermal therapy.

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The combination of the nucleus-targeted DIR825@histone and interventional laser harvested the best therapeutic outcomes against drug-resistant tumor.

Imaging of the thorax after percutaneous thermal ablation of lung malignancies

Image-guided thermal ablation is a minimally invasive treatment option for patients with early stage non-small cell lung cancer or metastatic disease to the lungs. Percutaneous ablation treats malignant tumours in situ, which precludes histopathological evaluation of the ablated tumours. Imaging studies are used as surrogates to assess technical and clinical success. Although it is not universally accepted, a common protocol for surveillance imaging includes contrast-enhanced computed tomography (CT) at 1, 3, 6, 9, 12, 18, 24 months, and yearly thereafter. Integrated 2-[¹⁸F]-fluoro-2-deoxy-d-glucose positron-emission tomography (PET)/CT imaging is recommended at 3 and 12 months and when recurrent disease is suspected. There is a complex evolution of the ablation zone on CT and PET imaging studies. The zone of ablation, initially larger than the ablated tumour, undergoes gradual involution. In the process, it may cavitate and resemble a lung abscess. Different contrast-enhancement and radionuclide uptake patterns in and around the ablation zone may indicate a wide range of diagnostic possibilities from a normal physiological response to local progression. Ultimately, the zone of ablation may be replaced by a variety of findings including linear bands of density, pleural thickening, or residual necrotic tumour. Diagnostic and interventional radiologists interpreting post-ablation imaging studies must have a clear understanding of the ablation process and imaging findings on surveillance studies. Accurate and timely recognition of complications and/or local recurrence is necessary to guide further therapy. The purpose of this article is to review imaging protocols and salient imaging findings after thermal ablation of lung malignancies.

A Systematic Review about Imaging and Histopathological Findings for Detecting and Evaluating Electroporation Based Treatments Response

BACKGROUND

Imaging methods and the most appropriate criteria to be used for detecting and evaluating response to oncological treatments depend on the pathology and anatomical site to be treated and on the treatment to be performed. This document provides a general overview of the main imaging and histopathological findings of electroporation-based treatments (Electrochemotherapy-ECT and Irreversible electroporation-IRE) compared to thermal approach, such as radiofrequency ablation (RFA), in deep-seated cancers with a particular attention to pancreatic and liver cancer.

METHODS

Numerous electronic datasets were examined: PubMed, Scopus, Web of Science and Google Scholar. The research covered the years from January 1990 to April 2021. All titles and abstracts were analyzed. The inclusion criteria were the following: studies that report imaging or histopathological findings after ablative thermal and not thermal loco-regional treatments (ECT, IRE, RFA) in deep-seated cancers including pancreatic and liver cancer and articles published in the English language. Exclusion criteria were unavailability of full text and congress abstracts or posters and different topic respect to inclusion criteria.

RESULTS

558 potentially relevant references through electronic searches were identified. A total of 38 articles met the inclusion criteria: 20 studies report imaging findings after RFA or ECT or IRE in pancreatic and liver cancer; 17 studies report histopathological findings after RFA or ECT or IRE; 1 study reports both imaging and histopathological findings after RFA or ECT or IRE.

CONCLUSIONS

Imaging features are related to the type of therapy administrated, to the timing of re-assessment post therapy and to the imaging technique being used to observe the effects. Histological findings after both ECT and IRE show that the treated area becomes necrotic and encapsulated in fibrous tissue, suggesting that the size of the treated lesion cannot be measured as an endpoint to detect response. Moreover, histology frequently reported signs of apoptosis and reduced vital tissue, implying that imaging criteria, which take into account the viability and not the size of the lesion, are more appropriate to evaluate response to treatment.

Positron Emission Tomography Imaging Evaluation of a Novel 18F-Labeled Sigma-1 Receptor Radioligand in Cynomolgus Monkeys

We report a convenient radiosynthesis and the first positron emission tomography (PET) imaging evaluation of [18F]FBFP as a potent sigma-1 (σ1) receptor radioligand with advantageous characteristics. [18F]FBFP was synthesized in one step from an iodonium ylide precursor. In cynomolgus monkeys, [18F]FBFP displayed high brain uptake and suitable tissue kinetics for quantitative analysis. It exhibited heterogeneous distribution with higher regional volume of distribution (VT) values in the amygdala, hippocampus, insula, and frontal cortex. Pretreatment with the σ1 receptor agonist SA4503 (0.5 mg/kg) significantly reduced radioligand uptake in the monkey brain (>95%), indicating high binding specificity of [18F]FBFP in vivo. Compared with (S)-[18F]fluspidine, [18F]FBFP possessed higher regional nondisplaceable binding potential (BPND) values across the brain regions. These findings demonstrate that [18F]FBFP is a highly promising PET radioligand for imaging and quantification of σ1 receptors in humans.

Short and Atom-Economic Enantioselective Synthesis of the σ1-Receptor Ligands (S)- and (R)-Fluspidine-Important Tools for Positron Emission Tomography Studies

Aryl bromides 2a and 2b bearing an alkynyl substituent in the o-position reacted with n-butyllithium and 1-benzylpiperidin-4-one in a one-pot Domino reaction to form ester 3 and aldehyde 5, respectively. Enantiomeric alcohols (R)-8 and (S)-8 were obtained by conjugate NaBH4 reduction of α,β-unsaturated ester 3 in the presence of chiral cocomplexes (R,R)-10 and (S,S)-10. Starting from orthoester 2a, the precursors (R)-8 and (S)-8 for the synthesis of fluspidine enantiomers (R)-1/[18F](R)-1 and (S)-1/[18F](S)-1 were obtained in only two reaction steps without additional steps for N-protection in an atom-economic manner in 95.6% ee and 97.2% ee, respectively.