First-Year Experience of IMRT/SBRT Treatments Using a Novel Biology-Guided Radiation Therapy System

PURPOSE/OBJECTIVE(S)

This study presents the first-year experience of treating patients using intensity-modulated radiation therapy (IMRT) and stereotactic body radiation therapy (SBRT) with the X1 system, the first biology-guided radiation therapy (BgRT) machine installed in a clinical setting.

MATERIALS/METHODS

A total of 78 patients underwent IMRT and SBRT treatments on the X1 system from May 2021 to May 2022. Clinical and technical data, such as treatment sites, number of pre-treatments kVCT scans, beam on time, patient setup time, imaging time per kVCT, and couch shifts after kVCT match, were collected and analyzed. Additionally, daily machine output stability, patient-specific quality assurance (QA) results, machine uptime, and user survey were also documented and reported.

RESULTS

The most commonly treated site was the head and neck (63%), followed by the pelvis (23%), thorax (6%), and abdomen (8%). All treatments, except for 5 pelvis patients (6%) who received SBRT treatments for bony metastases, were conventionally fractionated IMRT (CF IMRT). The average number of kVCT scans per fraction is 1.2 ± 0.5 for all treatments. The average beam on time in minutes was 9.2 ± 3.5 for all treatments, 8.4 ± 2.4 for head and neck, 6.7 ± 1.3 for thorax, 10.3 ± 1.6 for abdomen, 11.6 ± 5.1 for CF IMRT pelvis, and 10.8 ± 5.3 for SBRT pelvis. The average patient setup time and imaging time per kVCT was 4.8 ± 2.6 minutes and 4.6 ± 1.5 minutes, respectively. The average couch corrections based on kVCT images were 0.4 ± 4.4 mm, 1.0 ± 4.5 mm, and 1.3 ± 4.3 mm along the x, y, and z direction, respectively; the average couch rotation corrections were 0.1 ± 0.9° for pitch, 0.0 ± 0.9° for roll, and 0.2 ± 1.2° for yaw. The daily machine output was 0.4 ± 1.2% from the baseline. The patient QA had a gamma passing rate of 97.4 ± 2.8%. The machine uptime was 92% of the total treatment time. The kVCT image quality and daily QA process received the highest level of satisfaction, while the treatment workflow for therapists received the lowest level of satisfaction (table 1).

CONCLUSION

At one year after the installation of the X1 system, this study reports successful treatment of 78 patients using IMRT/ SBRT. With the recent FDA clearance of BgRT, our institution is preparing to treat patients using PET-guidance via a new product release, which should address deficiencies in the current IGRT workflow.

Is Banning Texturized Implants to Prevent Breast Implant-Associated Anaplastic Large Cell Lymphoma a Rational Decision? A Meta-Analysis and Cost-Effectiveness Study

BACKGROUND

Breast implant-associated anaplastic large cell lymphoma (BIA-ALCL) is an emergent disease that threatens patients with texturized breast implants. Major concerns about the safety of these implants are leading to global changes to restrict the utilization of this product. The principal alternative is to perform breast augmentation utilizing smooth implants, given the lack of association with BIA-ALCL. The implications and costs of this intervention are unknown.

OBJECTIVES

The authors of this study determined the cost-effectiveness of smooth implants compared with texturized implants for breast augmentation surgery.

METHODS

A tree decision model was utilized to analyze the cost-effectiveness. Model input parameters were derived from published sources. The capsular contracture (CC) rate was calculated from a meta-analysis. Effectiveness measures were life years, avoided BIA-ALCL, avoided deaths, and avoided reoperations. A sensitivity analysis was performed to test the robustness of the model.

RESULTS

For avoided BIA-ALCL, the incremental cost was $18,562,003 for smooth implants over texturized implants. The incremental cost-effectiveness ratio was negative for life years, and avoided death and avoided reoperations were negative. The sensitivity analysis revealed that to avoid 1 case of BIA-ALCL, the utilization of smooth implants would be cost-effective for a risk of developing BIA-ALCL equal to or greater than 1:196, and there is a probability of CC with smooth implants equal to or less than 0.096.

CONCLUSIONS

The utilization of smooth implants to prevent BIA-ALCL is not cost-effective. Banning texturized implants to prevent BIA-ALCL may involve additional consequences, which should be considered in light of higher CC rates and more reoperations associated with smooth implants than with texturized implants.

Selective activation of memristive interfaces in TaO x -based devices by controlling oxygen vacancies dynamics at the nanoscale

The development of novel devices for neuromorphic computing and non-traditional logic operations largely relies on the fabrication of well controlled memristive systems with functionalities beyond standard bipolar behavior and digital ON-OFF states. In the present work we demonstrate for Ta₂O₅-based devices that it is possible to selectively activate/deactivate two series memristive interfaces in order to obtain clockwise or counter-clockwise multilevel squared remanent resistance loops, just by controlling both the electroforming process and the (a)symmetry of the applied stimuli, and independently of the nature of the used metallic electrodes. Based on our thorough characterization, analysis and modeling, we show that the physical origin of this electrical behavior relies on controlled oxygen vacancies electromigration between three different nanoscopic zones of the active Ta₂O_5-x layer: a central one and two quasi-symmetric interfaces with reduced TaO_2-h(y) layers. Our devices fabrication process is rather simple as it implies the room temperature deposition of only one CMOS compatible oxide-Ta-oxide-and one metal, suggesting that it might be possible to take advantage of these properties at low cost and with easy scability. The tunable opposite remanent resistance loops circulations with multiple-analogic-intermediate stable states allows mimicking the adaptable synaptic weight of biological systems and presents potential for non-standard logic devices.

Predicting nationwide obesity from food sales using machine learning

The obesity epidemic progresses everywhere across the globe, and implementing frequent nationwide surveys to measure the percentage of obese population is costly. Conversely, country-level food sales information can be accessed inexpensively through different suppliers on a regular basis. This study applies a methodology to predict obesity prevalence at the country-level based on national sales of a small subset of food and beverage categories. Three machine learning algorithms for nonlinear regression were implemented using purchase and obesity prevalence data from 79 countries: support vector machines, random forests and extreme gradient boosting. The proposed method was validated in terms of both the absolute prediction error and the proportion of countries for which the obesity prevalence was predicted satisfactorily. We found that the most-relevant food category to predict obesity is baked goods and flours, followed by cheese and carbonated drinks.

Teamwork: relevance and interdependence of interprofessional education

OBJECTIVE

Determine the perception of university students regarding interprofessional and interdependent work between team members in their inclusion in primary care.

METHODS

Analytical cross-sectional study. The sampling had a probabilistic, stratified random type with 95% confidence and 5% margin of error. Seven-hundred and four students of Public Universities in Santiago (Chile) answered self-administered questionnaire.

RESULTS

Ninety-seven point eight of students say that interprofessional work is important; 27.1% of them declare that their university did not seem to show that their study plans were important. The professionals listed as most important in teams are physicians and nurses.

CONCLUSIONS

Spaces for development and institutional support are key elements to promote interprofessional work. If this competence can involve each academic unit in their different formative spaces there will be a significant contribution to said promotion. Teamwork is a pending task.

Challenges in simulating the human gut for understanding the role of the microbiota in obesity

There is an elevated incidence of cases of obesity worldwide. Therefore, the development of strategies to tackle this condition is of vital importance. This review focuses on the necessity of optimising in vitro systems to model human colonic fermentation in obese subjects. This may allow to increase the resolution and the physiological relevance of the information obtained from this type of studies when evaluating the potential role that the human gut microbiota plays in obesity. In light of the parameters that are currently used for the in vitro simulation of the human gut (which are mostly based on information derived from healthy subjects) and the possible difference with an obese condition, we propose to revise and improve specific standard operating procedures.

Synthesis of poly(methyl methacrylate) and block copolymers by semi-batch nitroxide mediated polymerization

The limits of control of the molecular weight and polymer structure in the semi-batch solution polymerization of methyl methacrylate by NMP are explored.

Design and Preliminary Evaluation of a Stiff Steerable Cutter for Arthroscopic Procedures

This article describes a novel and simple shaft actuated tip articulation (SATA) mechanism that allows arthroscopic instruments to articulate while remaining stiff. Since the SATA mechanism requires only independent rotation of two tubes for hinge articulation, cables, gears, or other internal components that are normally found in steerable endoscopic instruments become obsolete. The SATA mechanism was integrated in a new steerable cutter prototype and tested. Early user, mechanical strength and cadaver experiments were performed that indicate that this first prototype withstands an axial and sideways force of 100 N and 20 N, that trained users can (dis)assemble the instrument in less than 1.5 min and that a surgeon is able to reach all important locations on the menisci.

[Treatment of late onset Perthes disease with hip arthroscopy and arthrodiastasis with an external fixator. Case report]

BACKGROUND

The prognosis of late onset Perthes cases is usually poor and the proposed treatments vary based on the surgeon's preferences and experience, as well as on the available resources. Most of them are salvage procedures with a short follow-up and non-standardized application criteria.

METHODS

Hip arthroscopy and arthrodiastasis with external fixator are indicated for certain situations in Perthes disease. Based on the results obtained with each of these techniques separately, both of them were used to treat a case of Perthes disease involving a poor prognosis.

RESULTS

Results two years after surgery are good.

CONCLUSIONS

The use of both techniques together may produce a good result in these patients.

A pilot study of an enhanced mental health assessment during routine and discharge medicals in the British Armed Forces

OBJECTIVES

A pilot study to assess the practicality of introducing an enhanced mental health assessment (EMHA) into all routine and discharge medicals of the UK Armed Forces in order to facilitate treatment prior to and on return to civilian life.

METHODS

A pilot study was conducted using an EMHA questionnaire with questions about depression, anxiety, post-traumatic stress disorder, alcohol use, sleep and anger/irritability. At pilot sites, the EMHA was completed during all routine and discharge medicals between May 2011 and July 2011. At the end of the study period, qualitative data were collected from participating medical officers and practice managers regarding their opinions about the pilot study.

RESULTS

The quantitative data revealed an average pick-up rate for mental health (MH) problems. Out of the four military medical centres who participated and the 325 questionnaires collected, one referral to a Department of Community Mental Health was made. 26 (8%) patients were categorised as 'some concern and patient offered advice and/or reassurance'. The vast majority of patients were found to have no evidence of MH problems. However, using a validated alcohol screening tool, 64% of service personnel were found to have a score indicating 'higher risk drinking'. Analysis of the qualitative data suggests that the EMHA is an easy tool to implement with minimal additional time and resources needed. The interviewees pointed out a number of limitations and suggestions for possible further studies.

CONCLUSIONS

The pilot study successfully demonstrated that the EMHA questionnaire is easy to administer, does not take up a large amount of additional resources or manpower and provides a useful check of MH status. The study picked up an average number of MH cases and the questions on alcohol consumption highlighted that military personnel may be at a 'higher risk of drinking'.

Rotational Moulding and Powder Processing of Natural Fibre Reinforced Thermoplastics

The present paper describes the development of a new processing technology: rotational moulding of natural fibre reinforced thermoplastics. Different polymer-natural fibre and polymer-flour systems have been characterised. A rotomoulding grade of high density polyethylene has been used as the polymer matrix for the experiments. Fibres, including jute, sisal and cabuya, as well as wood, pecan and rice shell flour of different types have been used as reinforcements.

The rotomoulding process for those composite systems has been studied using an in-house built two-axis rotomoulding rig with variable speed. The final products have been characterised with special emphasis on estimating the level of dispersion of the fibres and their degree of orientation, as well as the consolidation, sintering and bubble formation processes during the different stages. Comparisons have been made with other powder processing routes, involving the sintering of fibre (or flour) reinforced polymer particles including compression moulding.

Morphological characterisation techniques have been adapted to determine the structure-property relationships in these materials at different processing stages. Important improvements in the compression strength of the natural fibre reinforced rotomoulded products compared to the unreinforced materials, accompanied of a good dispersion level of the reinforcing fibres have been reported.

Optimization of the mineralization of a mixture of phenolic pollutants under a ferrioxalate-induced solar photo-Fenton process

The mineralization of solutions containing a mixture of three phenolic compounds, gallic, p-coumaric and protocatechuic acids, in a ferrioxalate-induced solar photo-Fenton process was investigated. The reactions were carried out in a pilot plant consisting of a compound parabolic collector (CPC) solar reactor. An optimization study was performed combining a multivariate experimental design and neuronal networks that included the following variables: pH, temperature, solar power, air flow and initial concentrations of H(2)O(2), Fe(II) and oxalic acid. Under optimal conditions, total elimination of the original compounds and 94% TOC removal of the mixture were achieved in 5 and 194 min, respectively. pH and initial concentrations of H(2)O(2) and Fe(II) were the most significant factors affecting the mixture mineralization. The molar correlation between consumed hydrogen peroxide and removed TOC was always between 1 and 3. A detailed analysis of the reaction was presented. The values of the pseudo-first-order mineralization kinetic rate constant, k(TOC), increased as initial Fe(II) and H(2)O(2) concentrations and temperature increased. The optimum pH value also slightly increased with greater Fe(II) and hydrogen peroxide concentrations but decreased when temperature increased. OH and O(2)(-) radicals were the main oxidative intermediate species in the process, although singlet oxygen ((1)O(2)) also played a role in the mineralization reaction.

Mineralization of integrated gasification combined-cycle power-station wastewater effluent by a photo-Fenton process

The aim of this work was to study the mineralization of wastewater effluent from an integrated-gasification combined-cycle (IGCC) power station sited in Spain to meet the requirements of future environmental legislation. This study was done in a pilot plant using a homogeneous photo-Fenton oxidation process with continuous addition of H(2)O(2) and air to the system. The mineralization process was found to follow pseudo-first-order kinetics. Experimental kinetic constants were fitted using neural networks (NNs). The NNs model reproduced the experimental data to within a 90% confidence level and allowed the simulation of the process for any values of the parameters within the experimental range studied. At the optimum conditions (H(2)O(2) flow rate=120 mL/h, [Fe(II)]=7.6 mg/L, pH=3.75 and air flow rate=1 m(3)/h), a 90% mineralization was achieved in 150 min. Determination of the hydrogen peroxide consumed and remaining in the water revealed that 1.2 mol of H(2)O(2) was consumed per each mol of total organic carbon removed from solution. This result confirmed that an excess of dissolved H(2)O(2) was needed to achieve high mineralization rates, so continuous addition of peroxide is recommended for industrial application of this process. Air flow slightly improved the mineralization rate due to the formation of peroxo-organic radicals which enhanced the oxidation process.