Adaptive radiotherapy (ART) may improve treatment quality by monitoring variations in patient anatomy and incorporating them into the treatment plan. This systematic review investigated the role of artificial intelligence (AI) in computed tomography (CT)-based ART for head and neck (H&N) cancer. A comprehensive search of main electronic databases was conducted until April 2024. Titles and abstracts were reviewed to evaluate the compliance with inclusion criteria: CT-based imaging for photon ART of H&N patients and AI applications. 17 original retrospective studies with samples sizes ranging from 37 to 239 patients were included. The quality of the studies was evaluated with the Quality Assessment of Diagnostic Accuracy Studies-2 and the Checklist for Artificial Intelligence in Medical Imaging (CLAIM) tools. Key metrics were examined to evaluate the performances of the proposed AI-methods. Overall, the risk of bias was low. The average CLAIM score was 70%. A major finding was that generated synthetic CTs improved similarity metrics with planning CT compared to original cone-beam CTs, with average mean absolute error up to 39 HU and maximum improvement of 80%. Auto-segmentation provided an efficient and accurate option for organ-at-risk delineation, with average Dice similarity coefficient ranging from 80 to 87%. Finally, AI models could be trained using clinical and radiomic features to predict the effectiveness of ART with accuracy above 80%. Automation of processes in ART for H&N cancer is very promising throughout the entire chain, from the generation of synthetic CTs and auto-segmentation to predict the effectiveness of ART.

Magnetic resonance imaging (MRI) is a non-invasive powerful modern clinical technique that is extensively used for the high-resolution imaging of soft tissues. To obtain high-definition pictures of tissues or of the whole organism this technique is enhanced by the use of contrast agents. Gadolinium-based contrast agents have an excellent safety profile. However, over the last two decades, some specific concerns have surfaced. Mn(II) has different favorable physicochemical characteristics and a good toxicity profile, which makes it a good alternative to the Gd(III)-based MRI contrast agents currently used in clinics. Mn(II)-disubstituted symmetrical complexes containing dithiocarbamates ligands were prepared under a nitrogen atmosphere. The magnetic measurements on Mn complexes were carried out with MRI phantom measurements at 1.5 T with a clinical magnetic resonance. Relaxivity values, contrast, and stability were evaluated by appropriate sequences. Studies conducted to evaluate the properties of paramagnetic imaging in water using a clinical magnetic resonance showed that the contrast, produced by the complex [Mn(II)(L’)₂] × 2H₂O (L’ = 1.4-dioxa-8-azaspiro[4.5]decane-8-carbodithioate), is comparable to that produced by gadolinium complexes currently used in medicine as a paramagnetic contrast agent.

Purpose: In stereotactic body radiation therapy (SBRT) for prostate cancer, intrafraction motion is an important source of treatment uncertainty as it could not be completely smoothed through fractionation. Herein, we compared different arrangements and beam qualities for extreme hypofractionated treatments to minimize beam delivery time and so intrafractional errors. Methods: A retrospective dataset of 11 patients was used. Three volumetric modulated arc therapy (VMAT) beam arrangements were compared for a prescription dose of 40 Gy/5 fractions: two full arcs, 6 MV flattening filter free (FFF); one full arc, 6 MV FFF; one full arc, 10 MV FFF. A plan quality index was defined to compare achievement of the planning goals. Plan complexity was evaluated with the modulation factor. Dose delivery accuracy and efficiency were measured with patient-specific quality assurance plans. Results: All treatment plans fulfilled all dose objectives. No statistical differences were found both in plan quality and complexity. Very accurate dose delivery was achieved with the three arrangements, with mean gamma passing rates >96.5 % (2 %/2 mm criteria). Slightly but significantly higher gamma passing rates were observed with single-arc 6 MV FFF. Contrariwise, statistically significant reductions of the delivery time were obtained with single-arc geometries: the average delivery times were 1.6 min (-46.1 %) and 1.3 min (-56.2 %) for 6 and 10 MV FFF respectively. Conclusions: The high-quality, very fast and accurate dose delivery of single-arc plans confirmed the suitability of this arrangement for prostate SBRT. In particular, the significant reduction of delivery time would improve treatment robustness against intrafraction prostate motion.

The present study investigates the possible use of manganese (Mn)-based liposomal formulations for diagnostic applications in imaging techniques such as magnetic resonance imaging (MRI), with the aim of overcoming the toxicity limitations associated with the use of free Mn²⁺. Specifically, anionic liposomes carrying two model Mn(II)-based compounds, MnCl₂ (MC) and Mn(HMTA) (MH), were prepared and characterised in terms of morphology, size, loading capacity, and in vitro activity. Homogeneous dispersions characterised mainly by unilamellar vesicles were obtained; furthermore, no differences in size and morphology were detected between unloaded and Mn-loaded vesicles. The encapsulation efficiency of MC and MH was evaluated on extruded liposomes by means of ICP-OES analysis. The obtained results showed that both MC and MH are almost completely retained by the lipid portion of liposomes (LPs), with encapsulation efficiencies of 99.7% for MC and 98.8% for MH. The magnetic imaging properties of the produced liposomal formulations were investigated for application in a potential preclinical scenario by collecting magnetic resonance images of a phantom designed to compare the paramagnetic contrast properties of free MC and MH compounds and the corresponding manganese-containing liposome dispersions. It was found that both LP-MC and LP-MH at low concentrations (0.5 mM) show better contrast (contrast-to-noise ratios of 194 and 209, respectively) than solutions containing free Mn at the same concentrations (117 and 134, respectively) and are safe to use on human cells at the selected dose. Taken together, the results of this comparative analysis suggest that these liposome-containing Mn compounds might be suitable for diagnostic purposes.