Students experience the effects of climate change on children's health in role play and develop strategies for medical work - an interactive seminar.

Background: This project report describes the development and evaluation of an interactive seminar on the topic "medical effects of climate change on children's health". Objectives: The learning objectives are learning the basics and the direct and indirect connections between climate change and children's health. Future scenarios for affected children, parents and doctors are developed interactively. Subsequently, communication strategies concerning climate change are discussed so that students identify and analyze possibilities to become active. Methodology: The seminar was offered as an obligatory seminar for a total of 128 third-year medical students with one appointment of 45 minutes per course group as part of the interdisciplinary seminar series "Environmental Medicine". A course group consisted of 14 to 18 students. The seminar for the 2020 summer semester was developed as part of the interdisciplinary field of environmental medicine with the special feature of an interactive role play. The role play intends to give the students the opportunity to put themselves in the situation of affected children, parents and doctors of the future in order to develop detailed solution strategies. From 2020 to 2021, the seminar took place as online self-study due to the lockdown requirements. Since winter semester 2021/22, the seminar was held as an attendance event for the first time, although the switch to an online presence seminar with obligatory attendance had to take place after four seminar dates due to renewed lockdown requirements, which also took place four times. The evaluated results here refer to a total of eight dates in the winter semester 2021/22 and were carried out using a specially developed questionnaire, which was filled out voluntarily and anonymously by the students immediately after the respective seminar date. An overall grade as well as the appropriateness of the time and content of lectures and role play were asked for. Free text answers were possible for each question. Results: A total of 83 questionnaires were evaluated, 54 of which were from the four seminars in attendance, 15 were from the four online presence seminars that took place as an online live stream. The evaluation of the seminar resulted in an average grade of 1.7 for the face-to-face seminars and 1.9 for the online seminars. Content-related comments in the free-text answers addressed the desire for concrete solution strategies, more time for discussions and a more in-depth study of the topic. Numerous positive responses described the seminar as "very exciting", "good food for thought", "interesting and important topic". Conclusion: There is a very high interest on the topic of "climate change & health" among students There is an obvious need to integrate the topic on a larger scale into medical education. Ideally, the focus on children's health should be an integral part of the pediatric curriculum.

Consensus guide on CT-based prediction of stopping-power ratio using a Hounsfield look-up table for proton therapy.

BACKGROUND AND PURPOSE: Studies have shown large variations in stopping-power ratio (SPR) prediction from computed tomography (CT) across European proton centres. To standardise this process, a step-by-step guide on specifying a Hounsfield look-up table (HLUT) is presented here. MATERIALS AND METHODS: The HLUT specification process is divided into six steps: Phantom setup, CT acquisition, CT number extraction, SPR determination, HLUT specification, and HLUT validation. Appropriate CT phantoms have a head- and body-sized part, with tissue-equivalent inserts in regard to X-ray and proton interactions. CT numbers are extracted from a region-of-interest covering the inner 70% of each insert in-plane and several axial CT slices in scan direction. For optimal HLUT specification, the SPR of phantom inserts is measured in a proton beam and the SPR of tabulated human tissues is computed stoichiometrically at 100 MeV. Including both phantom inserts and tabulated human tissues increases HLUT stability. Piecewise linear regressions are performed between CT numbers and SPRs for four tissue groups (lung, adipose, soft tissue, and bone) and then connected with straight lines. Finally, a thorough but simple validation is performed. RESULTS: The best practices and individual challenges are explained comprehensively for each step. A well-defined strategy for specifying the connection points between the individual line segments of the HLUT is presented. The guide was tested exemplarily on three CT scanners from different vendors, proving its feasibility. CONCLUSION: The presented step-by-step guide for CT-based HLUT specification with recommendations and examples can contribute to reduce inter-centre variations in SPR prediction.

Dual-energy CT-based stopping power prediction for dental materials in particle therapy.

Radiotherapy with protons or light ions can offer accurate and precise treatment delivery. Accurate knowledge of the stopping power ratio (SPR) distribution of the tissues in the patient is crucial for improving dose prediction in patients during planning. However, materials of uncertain stoichiometric composition such as dental implant and restoration materials can substantially impair particle therapy treatment planning due to related SPR prediction uncertainties. This study investigated the impact of using dual-energy computed tomography (DECT) imaging for characterizing and compensating for commonly used dental implant and restoration materials during particle therapy treatment planning. Radiological material parameters of ten common dental materials were determined using two different DECT techniques: sequential acquisition CT (SACT) and dual-layer spectral CT (DLCT). DECT-based direct SPR predictions of dental materials via spectral image data were compared to conventional single-energy CT (SECT)-based SPR predictions obtained via indirect CT-number-to-SPR conversion. DECT techniques were found overall to reduce uncertainty in SPR predictions in dental implant and restoration materials compared to SECT, although DECT methods showed limitations for materials containing elements of a high atomic number. To assess the influence on treatment planning, an anthropomorphic head phantom with a removable tooth containing lithium disilicate as a dental material was used. The results indicated that both DECT techniques predicted similar ranges for beams unobstructed by dental material in the head phantom. When ion beams passed through the lithium disilicate restoration, DLCT-based SPR predictions using a projection-based method showed better agreement with measured reference SPR values (range deviation: 0.2 mm) compared to SECT-based predictions. DECT-based SPR prediction may improve the management of certain non-tissue dental implant and restoration materials and subsequently increase dose prediction accuracy.

Association of response time and intermittent hypoxemia in extremely preterm infants.

AIM: To determine the relationship between medical staff's response time (RT) to oxygen saturation (SpO2 ) below 80% and the associated time from tactile intervention until SpO2 normalisation (CT). METHODS: Time-lapse video and continuous SpO2 were recorded for six consecutive 24 h periods. Regression analyses of RT and SpO2 in association with postmenstrual age (PMA), weight, infant sex and frequency of intermittent hypoxemia (IH). RESULTS: Five hundred and twelve hypoxemia episodes received tactile intervention in 20 extremely preterm infants (gestational age ≤28 weeks, birthweight <1500 g). Median RT was 20.5 s (IQR 16.63-25.50). RT increased with increased IH frequency (p = 0.023) independently of PMA and weight. SpO2 decreased by 3.7% with every 10 s RT (p = 0.039). Time until SpO2 normalisation was strongly associated with RT (ß = 0.58, p = 0.042). The association was amplified by lower PMA (p = 0.043). Female preterm infants experienced longer RT than males (p = 0.027). Because the total length of an IH is the sum of RT and CT, preterm infants with low PMA can reach a critical hypoxemia duration of >60 s, even with short RT. CONCLUSION: The RT is a critical factor that affects the overall time of IH treatments and the depth of desaturation. The consequences of a prolonged RT are worse for more immature preterm infants.

Commissioning of Helium Ion Therapy and the First Patient Treatment With Active Beam Delivery.

PURPOSE: Helium ions offer intermediate physical and biological properties to the clinically used protons and carbon ions. This work presents the commissioning of the first clinical treatment planning system (TPS) for helium ion therapy with active beam delivery to prepare the first patients' treatment at the Heidelberg Ion-Beam Therapy Center (HIT). METHODS AND MATERIALS: Through collaboration between RaySearch Laboratories and HIT, absorbed and relative biological effectiveness (RBE)-weighted calculation methods were integrated for helium ion beam therapy with raster-scanned delivery in the TPS RayStation. At HIT, a modified microdosimetric kinetic biological model was chosen as reference biological model. TPS absorbed dose predictions were compared against measurements with several devices, using phantoms of different complexities, from homogeneous to heterogeneous anthropomorphic phantoms. RBE and RBE-weighted dose predictions of the TPS were verified against calculations with an independent RBE-weighted dose engine. The patient-specific quality assurance of the first treatment at HIT using helium ion beam with raster-scanned delivery is presented considering standard patient-specific measurements in a water phantom and 2 independent dose calculations with a Monte Carlo or an analytical-based engine. RESULTS: TPS predictions were consistent with dosimetric measurements and independent dose engines computations for absorbed and RBE-weighted doses. The mean difference between dose measurements to the TPS calculation was 0.2% for spread-out Bragg peaks in water. Verification of the first patient treatment TPS predictions against independent engines for both absorbed and RBE-weighted doses presents differences within 2% in the target and with a maximum deviation of 3.5% in the investigated critical regions of interest. CONCLUSIONS: Helium ion beam therapy has been successfully commissioned and introduced into clinical use. Through comprehensive validation of the absorbed and RBE-weighted dose predictions of the RayStation TPS, the first clinical TPS for helium ion therapy using raster-scanned delivery was employed to plan the first helium patient treatment at HIT.

High-frequency ventilation in preterm infants and neonates.

High-frequency ventilation (HFV) has been used as a respiratory support mode for neonates for over 30 years. HFV is characterized by delivering tidal volumes close to or less than the anatomical dead space. Both animal and clinical studies have shown that HFV can effectively restore lung function, and potentially limit ventilator-induced lung injury, which is considered an important risk factor for developing bronchopulmonary dysplasia (BPD). Knowledge of how HFV works, how it influences cardiorespiratory physiology, and how to apply it in daily clinical practice has proven to be essential for its optimal and safe use. We will present important aspects of gas exchange, lung-protective concepts, clinical use, and possible adverse effects of HFV. We also discuss the study results on the use of HFV in respiratory distress syndrome in preterm infants and respiratory failure in term neonates. IMPACT: Knowledge of how HFV works, how it influences cardiorespiratory physiology, and how to apply it in daily clinical practice has proven to be essential for its optimal and safe use. Therefore, we present important aspects of gas exchange, lung-protective concepts, clinical use, and possible adverse effects of HFV. The use of HFV in daily clinical practice in lung recruitment, determination of the optimal continuous distending pressure and frequency, and typical side effects of HFV are discussed. We also present study results on the use of HFV in respiratory distress syndrome in preterm infants and respiratory failure in term neonates.

Incidence of Intermittent Hypoxemia Increases during Clinical Care and Parental Touch in Extremely Preterm Infants.

OBJECTIVES: An increased frequency of intermittent hypoxemia (IH) is associated with a higher risk for poor developmental outcomes, disability, or death in extremely preterm infants. The objective of the prFesent study is to quantify the effect of hands-on medical and parental interventions on the incidence of IH in extremely preterm infants. METHODS: An observational design with intraindividual comparisons was used. Blood oxygen saturation levels (SpO2) and time-lapse video were recorded. Frequency, duration, and time to occurrence of IH (SpO2 <80% for ≥10 s) were compared between nursing and medical care (NMC), health care by parents, skin-to-skin contact (SSC), touch in incubator, physiotherapy, and rest. Each infant was observed for six consecutive 24-h periods. Inclusion criteria were as follows: gestational age ≤28 weeks, birth weight <1500 g, postnatal age 0-6 weeks, gavage feeding, no severe illnesses or invasive procedures, no mechanical ventilation. RESULTS: The highest proportion of time with IH occurred during NMC (2.49%) and incubator touch (1.32%), the lowest during SSC (0.74%) and health care by parents (0.67%). IH frequency per hour was highest during NMC (2.95, IQR 1.19-4.01) and lowest during SSC (0.88, IQR 0.37-2.32, p < 0.001). While an increase in IH during NMC was expected, the high incidence during incubator touch was surprising. Parental touch in the incubator is intended to be soothing, not stressful. CONCLUSIONS: Future studies need to clarify how preterm infants process touch, which attributes of touch are fundamental trigger mechanisms of IH, and which handling strategies are most effective in lowering the incidence of IH during hands-on medical care.

"Alcohol intoxication by proxy on a NICU" - a case report.

BACKGROUND: Ethanol intoxications in newborns are generally due to false preparation of formula with alcoholics or alcohol consumption by the breastfeeding mothers. Rarely, intoxications occur in hospitalized newborns, e.g., from excessive use of alcoholic hand sanitizers. We herein report a strange case of acute ethanol intoxications in our NICU. CASE PRESENTATION: An extremely premature infant (23 0/7 weeks gestational age, birthweight 580 g) suffered from repeated life-threatening events with hemodynamic compromise, apnea, and lactic acidosis while being treated in our neonatal intensive care unit (NICU). Symptomatic treatment with intravenous fluids and, if necessary, intubation and catecholamine therapy led to recovery after several hours each time. The episodes eventually turned out to be severe ethanol intoxications brought about by breast milk contaminated with ethanol. The breast milk was supplied by the infant's mother, who consumed non-trivial amounts of alcohol to build up her strength and make herself produce more milk, which was recommended to her by a family member. Additionally, she supplemented her own mother's milk with cow's milk because she was worried her baby was underserved with her milk. The mother admitted to this in intensive conversations with our team and a professional translator. CONCLUSIONS: This unique case underlines how different cultural dynamics can attribute to life-threatening events in the care of premature infants. It is important for us to emphasize that intensive communication and building a confident relationship with the parents of patients is essential to the work on NICUs. Child safeguarding issues and possibilities of intoxications have to stay in mind even in a supposedly safe space like the NICU.

Potential of a Second-Generation Dual-Layer Spectral CT for Dose Calculation in Particle Therapy Treatment Planning.

In particle therapy treatment planning, dose calculation is conducted using patient-specific maps of tissue ion stopping power ratio (SPR) to predict beam ranges. Improving patient-specific SPR prediction is therefore essential for accurate dose calculation. In this study, we investigated the use of the Spectral CT 7500, a second-generation dual-layer spectral computed tomography (DLCT) system, as an alternative to conventional single-energy CT (SECT) for patient-specific SPR prediction. This dual-energy CT (DECT)-based method allows for the direct prediction of SPR from quantitative measurements of relative electron density and effective atomic number using the Bethe equation, whereas the conventional SECT-based method consists of indirect image data-based prediction through the conversion of calibrated CT numbers to SPR. The performance of the Spectral CT 7500 in particle therapy treatment planning was characterized by conducting a thorough analysis of its SPR prediction accuracy for both tissue-equivalent materials and common non-tissue implant materials. In both instances, DLCT was found to reduce uncertainty in SPR predictions compared to SECT. Mean deviations of 0.7% and 1.6% from measured SPR values were found for DLCT- and SECT-based predictions, respectively, in tissue-equivalent materials. Furthermore, end-to-end analyses of DLCT-based treatment planning were performed for proton, helium, and carbon ion therapies with anthropomorphic head and pelvic phantoms. 3D gamma analysis was performed with ionization chamber array measurements as the reference. DLCT-predicted dose distributions revealed higher passing rates compared to SECT-predicted dose distributions. In the DLCT-based treatment plans, measured distal-edge evaluation layers were within 1 mm of their predicted positions, demonstrating the accuracy of DLCT-based particle range prediction. This study demonstrated that the use of the Spectral CT 7500 in particle therapy treatment planning may lead to better agreement between planned and delivered dose compared to current clinical SECT systems.

Dataset for predicting single-spot proton ranges in proton therapy of prostate cancer.

The number of radiotherapy patients treated with protons has increased from less than 60,000 in 2007 to more than 220,000 in 2019. However, the considerable uncertainty in the positioning of the Bragg peak deeper in the patient raised new challenges in the proton therapy of prostate cancer (PCPT). Here, we describe and share a dataset where 43 single-spot anterior beams with defined proton energies were delivered to a prostate phantom with an inserted endorectal balloon (ERB) filled either with water only or with a silicon-water mixture. The nuclear reactions between the protons and the silicon yield a distinct prompt gamma energy line of 1.78 MeV. Such energy peak could be identified by means of prompt gamma spectroscopy (PGS) for the protons hitting the ERB with a three-sigma threshold. The application of a background-suppression technique showed an increased rejection capability for protons hitting the prostate and the ERB with water only. We describe each dataset, document the full processing chain, and provide the scripts for the statistical analysis.

Towards real-time PGS range monitoring in proton therapy of prostate cancer.

Proton therapy of prostate cancer (PCPT) was linked with increased levels of gastrointestinal toxicity in its early use compared to intensity-modulated radiation therapy (IMRT). The higher radiation dose to the rectum by proton beams is mainly due to anatomical variations. Here, we demonstrate an approach to monitor rectal radiation exposure in PCPT based on prompt gamma spectroscopy (PGS). Endorectal balloons (ERBs) are used to stabilize prostate movement during radiotherapy. These ERBs are usually filled with water. However, other water solutions containing elements with higher atomic numbers, such as silicon, may enable the use of PGS to monitor the radiation exposure of the rectum. Protons hitting silicon atoms emit prompt gamma rays with a specific energy of 1.78 MeV, which can be used to monitor whether the ERB is being hit. In a binary approach, we search the silicon energy peaks for every irradiated prostate region. We demonstrate this technique for both single-spot irradiation and real treatment plans. Real-time feedback based on the ERB being hit column-wise is feasible and would allow clinicians to decide whether to adapt or continue treatment. This technique may be extended to other cancer types and organs at risk, such as the oesophagus.

PIBS: Proton and ion beam spectroscopy for in vivo measurements of oxygen, carbon, and calcium concentrations in the human body.

Proton and ion beam therapy has proven to benefit tumour control with lower side-effects, mostly in paediatrics. Here we demonstrate a feasible technique for proton and ion beam spectroscopy (PIBS) capable of determining the elemental compositions of the irradiated tissues during particle therapy. This follows the developments in prompt gamma imaging for online range verification and the inheritance from prompt gamma neutron activation analysis. Samples of water solutions were prepared to emulate varying oxygen and carbon concentrations. The irradiation of those samples and other tissue surrogate inserts by protons and ion beams under clinical conditions clearly showed a logarithmic relationship between the target elemental composition and the prompt gamma production. This finding is in line with the known logarithmic dependence of the pH with the proton molar concentration. Elemental concentration changes of 1% for calcium and 2% for oxygen in adipose, brain, breast, liver, muscle and bone-related tissue surrogates were clearly identified. Real-time in vivo measurements of oxygen, carbon and calcium concentrations will be evaluated in a pre-clinical and clinical environment. This technique should have an important impact in the assessment of tumour hypoxia over the course of several treatment fractions and the tracking of calcifications in brain metastases.

Pre-clinical evaluation of dual-layer spectral computed tomography-based stopping power prediction for particle therapy planning at the Heidelberg Ion Beam Therapy Center.

Accurate beam range prediction during clinical treatment planning is key to improve targeted dose delivery in proton and heavy ion therapy. A substantial source of beam range uncertainty is the prediction of ion stopping power ratio (SPR) relative to water from an empirical calibration based on conventional x-ray computed tomography (CT) used in clinical practice today. The aim of this study was to investigate the potential of a novel spectral CT imaging technique based on a dual-layer detector-based approach to improve the SPR prediction for particle therapy treatment planning, an improvement that would minimize the beam range uncertainty and allow for reduced safety margins in the patient. Using calibrated and validated maps of electron density and effective atomic number from spectral CT data, predicted SPR values in tissue substitutes were within a mean accuracy of 0.6% compared to measured SPR and showed substantially better agreement with measured data compared to standard CT-number-to-SPR calibration. The accuracy of SPR was not affected by CT acquisition settings, reconstruction parameters, phantom size, and type. Additionally, various spectral CT conversion algorithms were compared to determine the most accurate prediction method. Dosimetric validation of the developed method using a half-head anthropomorphic phantom in a routine-like setting indicated that SPR prediction with dual-layer spectral CT outperforms the clinical single-energy CT standard with a range prediction improvement of 1 mm. This study demonstrated in homogeneous and heterogeneous phantoms that spectral CT is feasible for particle therapy planning to improve range estimates for high-precision particle therapy.

Glucocorticoids Equally Stimulate Epithelial Na+ Transport in Male and Female Fetal Alveolar Cells.

Preterm infants frequently suffer from respiratory distress syndrome (RDS), possibly due to lower expression of epithelial Na+ channels (ENaC). RDS incidence is sex-specific, affecting males almost twice as often. Despite the use of antenatal glucocorticoids (GCs), the sex difference persists. It is still controversial whether both sexes benefit equally from GCs. We previously showed that Na+ transport is higher in female compared with male fetal distal lung epithelial (FDLE) cells. Since GCs increase Na+ transport, we hypothesized that their stimulating effect might be sex-specific. We analyzed FDLE cells with Ussing chambers and RT-qPCR in the presence or absence of fetal serum. In serum-free medium, GCs increased the ENaC activity and mRNA expression, independent of sex. In contrast, GCs did not increase the Na+ transport in serum-supplemented media and abolished the otherwise observed sex difference. Inhibition of the GC receptor in the presence of serum did not equalize Na+ transport between male and female cells. The GC-induced surfactant protein mRNA expression was concentration and sex-specific. In conclusion, female and male FDLE cells exhibit no sex difference in response to GCs with regard to Na+ transport, and GR activity does not contribute to the higher Na+ transport in females.

Dosimetric validation of Monte Carlo and analytical dose engines with raster-scanning 1H, 4He, 12C, and 16O ion-beams using an anthropomorphic phantom.

With high-precision radiotherapy on the rise towards mainstream healthcare, comprehensive validation procedures are essential, especially as more sophisticated technologies emerge. In preparation for the upcoming translation of novel ions, case-/disease-specific ion-beam selection and advanced multi-particle treatment modalities at the Heidelberg Ion-beam Therapy Center (HIT), we quantify the accuracy limits in particle therapy treatment planning under complex heterogeneous conditions for the four ions (1H, 4He, 12C, 16O) using a Monte Carlo Treatment Planning platform (MCTP), an independent GPU-accelerated analytical dose engine developed in-house (FRoG) and the clinical treatment planning system (Syngo RT Planning). Attaching an anthropomorphic half-head Alderson RANDO phantom to entrance window of a dosimetric verification water tank, a cubic target spread-out Bragg peak (SOBP) was optimized using the MCTP to best resolve effects of anatomic heterogeneities on dose homogeneity. Subsequent forward calculations were executed in FRoG and Syngo. Absolute and relative dosimetry was performed in the experimental beam room using 1D and 2D array ionization chamber detectors. Mean absolute percent deviation in dose (|%Δ|) between predictions and PinPoint ionization chamber measurements were within ∼2% for all investigated ions for both MCTP and FRoG. For protons and carbon ions, |%Δ| values were ∼4% for Syngo. For the four ions, 3D-γ analysis (3%/3mm criteria) of FLUKA and FRoG presented mean passing rates of 97.0(±2.4)% and 93.6(±4.2)%. FRoG demonstrated satisfactory agreement with gold standard Monte Carlo simulation and measurement, superior to the commercial system. Our pre-clinical trial landmarks the first measurements taken in anthropomorphic settings for helium, carbon and oxygen ion-beam therapy.