Additive manufacturing of patient specific bolus for radiotherapy: large scale production and quality assurance.

Bolus is commonly used to improve dose distributions in radiotherapy in particular if dose to skin must be optimised such as in breast or head and neck cancer. We are documenting four years of experience with 3D printed bolus at a large cancer centre. In addition to this we review the quality assurance (QA) program developed to support it. More than 2000 boluses were produced between Nov 2018 and Feb 2023 using fused deposition modelling (FDM) printing with polylactic acid (PLA) on up to five Raise 3D printers. Bolus is designed in the radiotherapy treatment planning system (Varian Eclipse), exported to an STL file followed by pre-processing. After checking each bolus with CT scanning initially we now produce standard quality control (QC) wedges every month and whenever a major change in printing processes occurs. A database records every bolus printed and manufacturing details. It takes about 3 days from designing the bolus in the planning system to delivering it to treatment. A 'premium' PLA material (Spidermaker) was found to be best in terms of homogeneity and CT number consistency (80 HU +/- 8HU). Most boluses were produced for photon beams (93.6%) with the rest used for electrons. We process about 120 kg of PLA per year with a typical bolus weighing less than 500 g and the majority of boluses 5 mm thick. Print times are proportional to bolus weight with about 24 h required for 500 g material deposited. 3D printing using FDM produces smooth and reproducible boluses. Quality control is essential but can be streamlined.

Cellulose-Based Metallogels-Part 3: Multifunctional Materials.

The incorporation of the metal phase into cellulose hydrogels, resulting in the formation of metallogels, greatly expands their application potential by introducing new functionalities and improving their performance in various fields. The unique antiviral, antibacterial, antifungal, and anticancer properties of metal and metal oxide nanoparticles (Ag, Au, Cu, CuxOy, ZnO, Al2O3, TiO2, etc.), coupled with the biocompatibility of cellulose, allow the development of composite hydrogels with multifunctional therapeutic potential. These materials can serve as efficient carriers for controlled drug delivery, targeting specific cells or pathogens, as well as for the design of artificial tissues or wound and burn dressings. Cellulose-based metallogels can be used in the food packaging industry to provide biodegradable and biocidal materials to extend the shelf life of the goods. Metal and bimetallic nanoparticles (Au, Cu, Ni, AuAg, and AuPt) can catalyze chemical reactions, enabling composite cellulose hydrogels to be used as efficient catalysts in organic synthesis. In addition, metal-loaded hydrogels (with ZnO, TiO2, Ag, and Fe3O4 nanoparticles) can exhibit enhanced adsorption capacities for pollutants, such as dyes, heavy metal ions, and pharmaceuticals, making them valuable materials for water purification and environmental remediation. Magnetic properties imparted to metallogels by iron oxides (Fe2O3 and Fe3O4) simplify the wastewater treatment process, making it more cost-effective and environmentally friendly. The conductivity of metallogels due to Ag, TiO2, ZnO, and Al2O3 is useful for the design of various sensors. The integration of metal nanoparticles also allows the development of responsive materials, where changes in metal properties can be exploited for stimuli-responsive applications, such as controlled release systems. Overall, the introduction of metal phases augments the functionality of cellulose hydrogels, expanding their versatility for diverse applications across a broad spectrum of industries not envisaged during the initial research stages.

Assessment of lung doses in patients undergoing total body irradiation for haematological malignancies with and without lung shielding.

INTRODUCTION: Total body irradiation (TBI) practices vary considerably amongst centres, and the risk of treatment related toxicities remains unclear. We report lung doses for 142 TBI patients who underwent either standing TBI with lung shield blocks or lying TBI without blocks. METHODS: Lung doses were calculated for 142 TBI patients treated between June 2016 and June 2021. Patients were planned using Eclipse (Varian Medical Systems) using AAA_15.6.06 for photon dose calculations and EMC_15.6.06 for electron chest wall boost fields. Mean and maximum lung doses were calculated. RESULTS: Thirty-seven patients (26.2%) were treated standing using lung shielding blocks with 104 (73.8%) treated lying down. Lowest relative mean lung doses were achieved using lung shielding blocks in standing TBI, reducing the mean lung doses to 75.2% of prescription (9.9 Gy), ±4.1% (range 68.6-84.1%) for a prescribed dose of 13.2 Gy in 11 fractions, including contributions from electron chest wall boost fields, compared to 12 Gy in 6 fraction lying TBI receiving 101.6% mean lung dose (12.2 Gy) ±2.4% (range 95.2-109.5%) (P ≪ 0.05). Patients treated lying down with 2 Gy single fraction received the highest relative mean lung dose on average, with 108.4% (2.2 Gy) ±2.6% of prescription (range 103.2-114.4%). CONCLUSION: Lung doses have been reported for 142 TBI patients using the lying and standing techniques described herein. Lung shielding blocks significantly reduced mean lung doses despite the addition of electron boost fields to the chest wall.

Selection of motion management in liver stereotactic body radiotherapy and its impact on treatment time.

Background and purpose: Reduction of respiratory tumour motion is important in liver stereotactic body radiation therapy (SBRT) to reduce side effects and improve tumour control probability. We have assessed the distribution of use of voluntary exhale breath hold (EBH), abdominal compression (AC), free breathing gating (gating) and free breathing (FB), and the impact of these on treatment time. Materials and Methods: We assessed all patients treated in a single institution with liver SBRT between September 2017 and September 2021. Data from pre-simulation motion management assessment using fluoroscopic assessment of liver dome position in repeat breath holds, and motion with and without AC, was reviewed to determine liver dome position consistency in EBH and the impact of AC on motion. Treatment time was assessed for all fractions as time from first image acquisition to last treatment beam off. Results: Of 136 patients treated with 145 courses of liver SBRT, 68 % were treated in EBH, 20 % with AC, 7 % in gating and 5 % in FB. AC resulted in motion reduction < 1 mm in 9/26 patients assessed. Median treatment time was higher using EBH (39 min) or gating (42 min) compared with AC (30 min) or FB (24 min) treatments. Conclusions: Motion management in liver SBRT needs to be assessed per-patient to ensure appropriate techniques are applied. Motion management significantly impacts treatment time therefore patient comfort must also be taken into account when selecting the technique for each patient.

Occurrence of Potentially Toxic Elements in Bottled Drinking Water-Carcinogenic and Non-Carcinogenic Risks Assessment in Adults via Ingestion.

The presence of potentially toxic elements in drinking water can be dangerous for human health because of their bioaccumulation and toxicity, which is a huge concern for many researchers. In the case of bottled water, the exposure to toxic elements is achieved, especially by ingestion, leading to disorders of important functions of the human body. The aim of this study was the detection of some potentially toxic elements, from 50 samples of bottled drinking water, available on the Romanian market. Based on obtained concentrations, an assessment of the carcinogenic and non-carcinogenic health risk was performed. The concentrations of potentially toxic elements analyzed were below the maximum allowable limits, for all contaminants, excluding Pb and Fe. Moreover, the results of total risk via ingestion, showed that 30% of samples had an Hazard Quotient (HQ) < 1, and 70% had an HQ > 1; which implies a potential risk following the consumption of those samples. Concerning total cancer risk, 28% of the samples are in the acceptable level, while 72% of the samples are considered harmful and can lead to a type of cancer after repeated exposure. The study concluded that long term use of bottled water of poor quality may pose a hazard to human health; it is helpful for inhabitants to avoid ingestion of contaminated water.

Risk Assessment of Lead and Cadmium in Some Food Supplements Available on the Romanian Market.

Across the world, there has been an increase in the consumption of food supplements. This may be due to the perception that these dietary supplements cannot negatively affect the health of consumers in any way. However, dietary supplements may not have the expected effect. In addition, it has been shown that supplements can sometimes be chemically, physically or microbiologically contaminated, if the hygiene conditions and Hazard Analysis Critical Control Points (HACCP) plan are not fully complied with. The aim of this study was to determine the lead and cadmium content of 41 food supplements available on the Romanian market and to assess the risk to consumer health. The graphite furnace atomic absorption spectrometry (GFAAS) technique was used for sample analysis after wet mineralization of the samples. The risk assessment was determined based on Estimated Daily Intake (EDI), Target Hazard Quotient (THQ), and Carcinogenic Risk (CR) calculations. Values obtained for both lead and cadmium fall within the limits imposed by the legislation in force. Small risks associated with the consumption of these food supplements was shown, with a main recommendation being to decrease the recommended daily dose in the case of food supplements.

Total body irradiation in Australia and New Zealand: results of a practice survey.

Total body irradiation (TBI) is an important treatment modality for the preparation of patients for bone marrow transplants. It is technically challenging and the actual delivery may vary from clinic to clinic. Knowledge of the pattern of practice may be helpful for clinics to determine future practice. We carried out an email survey from April to September 2019 sending 48 TBI related questions to all radiotherapy clinics in Australia and New Zealand via the Australasian College of Physical Scientists in Medicine email distribution list. Centres not performing TBI were not expected to complete the survey and centres that had participated in a previous survey, or that were known to perform the treatment, were followed up if no response was received. Of a total of approximately 70 centres, 14 clinics responded to the survey. The vast majority of clinics use conventional lateral and/or anterior-posterior beams at extended SSD for TBI treatment delivery. However, treatment planning, ancillary equipment (used for immobilisation/modulation), beam energy and prescribed lung doses vary considerably-with some clinics delivering the prescription dose to the lungs and some aiming to deliver a lung dose which is lower than the prescription dose. Only one clinic reported using an advanced delivery technique with modulated arcs at extended SSD. Centres either said they had no access to outcome data or did not answer this question. Compared with an earlier survey from 2005, 3 clinics have lowered their linac dose rate and 7 are the same or similar. The TBI practice in Australia and New Zealand remains varied, with considerable differences in treatment planning, beam energy, accepted lung doses and delivered dose rates.

Independent review of 4DCT scans used for SABR treatment planning.

Four-dimensional computerized tomography (4DCT) is required for stereotactic ablative body radiotherapy (SABR) of mobile targets to account for tumor motion during treatment planning and delivery. In this study, we report on the impact of an image review quality assurance process performed prior to treatment planning by medical physicists for 4DCT scans used for SABR treatment. Reviews were performed of 211 4DCT scans (193 patients) over a 3-yr period (October 2014 to October 2017). Treatment sites included lung (n = 168), kidney/adrenal/adrenal gland (n = 12), rib (n = 4), mediastinum (n = 10), liver (n = 2), T-spine (n = 1), and other abdominal sites (n = 14). It was found that in 23% (n = 49) of cases patient management was altered due to the review process. The most frequent intervention involved patient-specific contouring advice (n = 35 cases, 17%) including adjustment of internal target volume (ITV) margins. In 13 cases (6%) a rescan was requested due to extensive motion artifact rendering the scan inadequate for SABR treatment planning. 4DCT review by medical physicists was found to be an effective method to improve plan quality for SABR.

CUPRAC Voltammetric Determination of Antioxidant Capacity in Tea Samples by Using Screen-Printed Microelectrodes.

Measurement of antioxidant capacity represents an analytical major challenge in terms of accuracy, efficiency, rapid response, or low cost of detection methods. Quantification of antioxidant capacity of food samples using disposable screen-printed microelectrodes (SPMEs) was based on cyclic voltammetry versus open-circuit potential (CV vs OCP) and differential pulse voltammetry (DPV) as compared with spectrophotometric measurement of the CUPRAC reaction with 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (trolox). The SPMEs are organic-resistant electrodes and thus compatible with food samples and organic solvents used to dissolve trolox. A micropipette was used to release a drop of 50 µL sample on the spotted surface of the SPME sensor/working electrode that was time programmed to function according to the working protocol. The SPME response was linearly correlated with trolox content. This preliminary demonstration was focused on the analysis of tea infusions, due to the simplicity and reproducibility of the samples' preparations involved. Analytical results of the antioxidant capacity (expressed as mol·L-1 trolox equivalents) of the tea samples showed a good agreement in the case of spectrophotometry and differential pulse voltammetry (R 2 > 0.998). DPV with SPME based on CUPRAC reactions was proven to be a promising approach for the characterization of antioxidant capacity of tea samples with rapid response, cost-effectiveness, and simplicity of operation.

PSYCHOTIC DISORDERS GENERATED BY AUTOIMMUNE ENCEPHALITIS (CLINICAL CASE).

Encephalitis is a brain inflammation, which could involve also the meninges. The etiology of encephalitis could be: viral, bacterial, fungal or autoimmune. Anti-NMDAR encephalitis is an immune disorder, easy to diagnose and is a treatable condition. Most patients with anti-NMDAR encephalitis develop a multistage illness that progresses from psychosis, memory deficits, seizures, to catatonic state and breathing instability. We present a case report of a 20-year old woman, who presented: amnesia, visual hallucination, illusions, seizures after that occurred following autoimmune encephalitis. The exact incidence of anti-NMDAR encephalitis is unknown, but it seems to be more frequent than any other known paraneoplastic encephalitis. The present case is important considering that autoimmune encephalitis is a rare frequency disorder in Romania, with patients presenting resounding psychiatric and neurological manifestations.