Maintaining High Quality Dosimetry Education in Radiation Oncology Medical Residency Amid and Post-COVID-19 Pandemic: A Reimagined Training Rotation

Background The Mayo Clinic radiation oncology medical residency program has maintained a dedicated medical dosimetry rotation since 1996. During this one-month rotation, residents practice and complete treatment plans under the supervision of certified medical dosimetrists. Skill development includes image fusions, contouring, treatment planning, and plan review all occurring in a one-on-one face-to-face educational environment. During the COVID-19 pandemic, our department incorporated dosimetry telework, and the rotation was modified into remote experience with an emphasis on creating enduring content while still maintaining a high-quality educational rotation. Methods In early 2020, the medical residency and dosimetry program leaders evaluated the state of the resident rotation with the goal of identifying areas of the rotation that could be made into enduring content, modernizing the objectives of the rotation, and adapting the face-to-face educational experience into a virtual environment. The new goals and platform were implemented in January 2022. Evaluations pre and post implementation were reviewed. Results After education committee review, goals and objectives were updated to reflect current practice. The rotation was restructured into a disease-site specific approach, with shared supervision by disease site, rather than a single dosimetry mentor. Site-specific standard of practice (SOP) documentation and twenty-four step-by-step tutorial videos teaching 3D and inverse treatment planning techniques were created. Virtual practice scenarios were created to ensure the appropriate breadth of experience. After onboarding for the rotation, residents reviewed site-specific SOP documentation and training tutorials while planning virtual cases independently, under disease site-specific dosimetry supervision. Virtual interactive plan review sessions of both practice and actual patients were performed through Microsoft Teams with supervising dosimetrists. Medical resident evaluation of the dosimetry rotation pre- and post- pandemic were collected via survey. Preliminary feedback on the recent implementation of enduring content and remote environment education have been positive, citing high quality content and satisfaction with virtual learning platform from residents. Raw data collection is currently in progress. Mentor feedback also cited improved rotation quality with enhanced efficiency of one-on-one instructional time. Discussion As the telework environment continues to evolve;the initial results of the restructured rotation present a positive outlook on the future of remote education and the success of enduring content from the perspective of both medical residents and dosimetrists. These results may also translate to the evolution of other aspects of the residency program. Further enhancements of the rotation including rotational assessments and attending physician interaction are planned for future resident rotations.

Effectiveness of protective thyroid shield in chest X-ray imaging.

Chest X-ray imaging is the most common X-ray imaging method for diagnosing coronavirus disease. The thyroid gland is one of the most radiation-sensitive organs of the body, particularly in infants and children. Therefore, it must be protected during chest X-ray imaging. Yet, because it has benefits and drawbacks, using a thyroid shield as protection during chest X-ray imaging is still up for debate.Therefore, this study aims to clarify the need for using a protective thyroid shield during chest X-ray imaging. This study was performed using different dosimeters (silica beads as a thermoluminescent dosimeter and an optically stimulated luminance dosimeter) embedded in an adult male ATOM dosimetric phantom. The phantom was irradiated using a portable X-ray machine with and without thyroid shielding. The dosimeter readings indicated that a thyroid shield reduced the radiation dose to the thyroid gland by 69% ± 18% without degrading the obtained radiograph. The use of a protective thyroid shield during chest X-ray imaging is recommended because its benefits outweigh the risks.

Leading past COVID-19: An analysis of remote work now and beyond.

In response to the coronavirus disease 2019 (COVID-19) pandemic, many cancer centers and clinics deployed remote work options for their employees. Due to the rapid response needed during this crisis, little to no feedback was obtained from dosimetrists. This study aimed to assess the productivity level and job satisfaction of medical dosimetrists in response to changes in working conditions due to the COVID-19 pandemic. With the assistance from the medical dosimetrists certification board (MDCB), critical data was gathered via an original instrument conducted and distributed by The University of Texas MD Anderson Cancer Center-School of Health Professions to all current practicing certified medical dosimetrists registered with the MDCB. Data were collected using Qualtrics and analyzed with IBM's SPSS. Most (326, 77.7%) participants indicated they transitioned to a version of remote work due to COVID-19. Almost half of the participants (208, 49.5%) reported increased job satisfaction due to the option to work remotely. The participants reported being extremely satisfied with the individual (247, 58.8%) and department (201, 47.9%) productivity levels even after implementing remote work options. Most participants (225, 53.6%), independent of age and years of experience, would prefer to stay in a hybrid role even after COVID-19 abates. These findings suggest that most dosimetrists prefer to perform their job remotely or asynchronously. A one size fits all job model design may make it difficult for organizations to attract, retain, and grow top dosimetrists. Industry leaders and employers may benefit by embracing this change as dosimetrists may value work-set-up flexibility over other employer-based benefits. Further research is needed to assess the unintended consequences of remote work environments in this profession.

Comparing dosimetry of locally advanced cervical cancer patients treated with 3 versus 4 fractions of MRI-guided brachytherapy.

PURPOSE: To demonstrate the feasibility of treating cervical cancer patients with MRI-guided brachytherapy (MRgBT) using 24 Gy in 3 fractions (F) versus a standard, more resource-intensive regimen of 28 Gy in 4F, and its ability to meet EMBRACE II planning aims. METHODS AND MATERIALS: A retrospective review of 224 patients with FIGO Stage IB-IVA cervical cancer treated with 28 Gy/4F (n = 91) and 24 Gy/3F (n = 133) MRgBT between 2016-2021 was conducted. Multivariable linear regression models were fitted to compare dosimetric parameters between the two groups, adjusting for CTVHR and T stage. RESULTS: Most patients had squamous cell carcinoma, T2b disease, and were treated with intracavitary applicator plus interstitial needles (96%). The 28 Gy/4F group had higher CTVHR (median 28 vs. 26 cm3, p = 0.04), CTVIR D98% (mean 65.5 vs. 64.5 Gy, p = 0.03), rectum D2cm3 (mean 61.7 vs. 59.2 Gy, p = 0.04) and bladder D2cm3 (81.3 vs. 77.9 Gy, p = 0.03). There were no significant differences in the proportion of patients meeting the EMBRACE II OAR dose constraints and planning aims, except fewer patients treated with 28 Gy/4F met rectum D2cm3 < 65 Gy (73 vs. 85%, p = 0.027) and ICRU rectovaginal point < 65 Gy (65 vs. 84%, p = 0.005). CONCLUSIONS: Cervical cancer patients treated with 24 Gy/3F MRgBT had comparable target doses and lower OAR doses compared to those treated with 28 Gy/4F. A less-resource intense fractionation schedule of 24 Gy/3F is an alternative to 28 Gy/4F in cervix MRgBT.

Medical dosimetry virtual clinical education: Mentors' perspectives.

The COVID-19 pandemic affected the United States in early 2020, and many universities began offering their curriculum remotely. The majority of medical dosimetry programs started to offer both didactic and clinical education in a virtual setting. With COVID-19 social distancing and patient protective measures, many clinical medical dosimetrists also began to work in a remote or hybrid setting. Medical dosimetry students interact and learn from their clinical mentors in this remote clinical environment. The purpose of this study was to investigate the perspective of medical dosimetry mentors concerning the effectiveness of virtual clinical education for medical dosimetry students as a result of COVID-19. The Medical Dosimetry Mentor Perspective on Virtual Clinical Education (MedDos_VCE) survey measured medical dosimetry mentors' perceptions of the students' virtual clinical experience during the COVID-19 pandemic. The subject of the study was medical dosimetry mentors who participated in a remote clinic due to the COVID-19 pandemic since March 2020. The MedDos_VCE questionnaire measured (1) the mentors' assessment of instructional quality in remote clinical education; (2) opportunities for and quality of interaction between students and medical dosimetry mentors; and (3) suggestions for success from medical dosimetry mentors for students and other mentors who are participating in virtual clinical education. The majority of the clinical mentors were satisfied with the quality of virtual clinical education and students' learning outcomes. They felt that students experienced a good mix of patients, problems, and clinical experience and engaged in the day-to-day activities of a medical dosimetrist. Challenges exist and mentors offered practical suggestions for success for students and mentors in the virtual clinical environment.

Safety, Biodistribution, and Dosimetry Study of Meplazumab, a Potential COVID-19 Therapeutic Drug, with 131I-Labeling and SPECT Imaging.

Coronavirus disease 2019 (COVID-19) is a serious threat to public health and is in urgent need of specific drugs. Meplazumab, a humanized monoclonal antibody targeting CD147, was confirmed to competitively block the binding between the spike of syndrome coronavirus 2 (SARS-CoV-2) and CD147, making meplazumab a promising candidate drug for COVID-19. In this study, biodistribution and dosimetry of 131I-labeled meplazumab were performed to further evaluate its potential as a therapeutic drug for COVID-19. 131I-meplazumab was both safe and tolerant in mice and healthy volunteers. A biodistribution study was performed in normal mice, and blood samples were used for pharmacokinetic analysis. Three healthy volunteers were included and subjected to single-photon-emission computed tomography (SPECT) imaging of 131I-meplazumab within 2 weeks. The distribution in mice and humans was consistent with the in vivo distribution of CD147. Biodistribution and SPECT imaging results exhibited that the liver was the organ with the highest uptake for both mice and humans. Deiodination of 131I-meplazumab can be observed in vivo, and taking Lugol's solution can protect the thyroid gland effectively. The pharmacokinetic characteristics of 131I-meplazumab in mice and humans best fit the two-compartment model. The clearance half-life (T1/2ß) in mice and humans was 117.4 and 223.5 h, respectively. The results indicated that its pharmacokinetic properties in vivo were ideal. The effective dose calculated from healthy volunteers was 0.811 ± 0.260 mSv·MBq-1, which was twice the value calculated from mice. It was safe and feasible to perform human clinical imaging experiments using a diagnostic dose of 131I-meplazumab after thyroid closure by Lugol's solution. This study will provide more experimental basis for advancing the clinical translation of meplazumab and will be valuable in evaluating therapeutic interventions for patients with COVID-19, as well as providing a reference for clinical translation studies of other antibody drugs.

Definitive Management of Cervical Cancer Patients at an Urban Institution During the COVID-19 Pandemic - Brachytherapy Treatment During the Surge

Purpose: Locally advanced cervical cancer was defined by an international consensus panel as a high priority malignancy during the COVID-19 pandemic, recommending prompt initiation of definitive treatment and completion of treatment (PMID 32563593). The objective of this study was to study the clinical outcomes of patients (pts) with cervical cancer treated with definitive chemoradiation (CRT) and brachytherapy (BT) at our institution in 2019 (pre-COVID) and in 2020 (peri-COVID). Material(s) and Method(s): This was a retrospective cohort study of pts with FIGO Stage IB2-IVA cervical cancer at our institutions from 1/1/2019 to 12/31/2020. Pts received CRT followed by intracavitary brachytherapy (IC) with two operative insertions one week apart, or interstitial (IS) BT with one operative insertion. BT treatment was planned using image-guided CT or MR delineation. Pre-COVID was defined by initiation of CRT in 1/2019-12/2019, and peri-COVID was defined by initiation in 1/2020-10/2020. Process changes peri-COVID included limited on-site staff (e.g., minimal OR staff, no trainees, remote physics team), universal implementation of COVID-19 testing prior to surgery, and CT instead of MR-delineation based treatment. Outcomes of interest were time to treatment initiation and completion and differences in treatment planning modality or dosimetry. Fisher's exact and Mann Whitney U tests were used with significance p<0.05. Result(s): Thirty-one pts were included, with 18 patients undergoing treatment pre-COVID and 13 peri-COVID. The median age at diagnosis pre-COVID was 57.7 (range 23-77) and for peri-COVID, 45.5 (range 28-62, p=0.06). There were no differences in non-English speaking pts (44% vs 59%, p=0.71) or uninsured pts (11% vs 33%, p=0.184) between the two cohorts. Median time to initiation of treatment from biopsy diagnosis was 52 days (range 13-209) in 2019 and for peri-COVID, 55.5 (range 20-173, p=0.71). During COVID, four pts had delayed initiation to treatment >100 days: two related to fertility, and one due to fear of COVID-19. For this pt, tumor size progressed from 2.3 cm to 4.2 cm maximal dimension. One pt treated in 2020 tested positive following treatment and did not require hospital admission. All pts except one completed CRT with RT: 25 pts pelvic RT (45 Gy), 3 pelvic and para-aortic RT (45 Gy with 57.5 Gy concomitant boost to nodes), 8 pts pelvic RT (45Gy) with sequential parametrial boost (50.4-59.4 Gy) using IMRT with no dose differences between pre and peri-COVID (Table 1). No pts required treatment breaks and the median overall treatment time was 50 days (range 31-85) in 2019 vs 50 days (range 43-63) in 2020 (p=0.710). Conclusion(s): Despite the significant burden of the COVID-19 pandemic on our health care system, all cervical cancer pts receiving CRT met standard of care including CRT and BT within the recommended time frame with no significant differences in dosimetric treatment parameters pre- and peri-COVID. Delays in treatment initiation of treatment initiation were seen in 30% of pts in the peri-COVID period, suggesting that patients may have had increased barriers to access care. More follow-up is needed to determine how the Covid pandemic impacted cervical cancer outcome measures. Copyright © 2022

Low Toxicity and Excellent Cosmesis with Highly Conformal Accelerated Partial Breast Irradiation Delivered Either Twice Daily or Every Other Day

Two landmark randomized controlled trials (RCT) of external beam accelerated partial breast irradiation (EB-APBI) using 38.5 Gy/10 fractions (F) BID demonstrated excellent cancer control outcomes in appropriately selected patients but conflicting results regarding cosmesis. A recent RCT reported high rates of acceptable cosmesis using 30 Gy/5F QOD, making the most appropriate schedule for EB-APBI unclear. We utilized the BID regimen largely until the COVID-19 pandemic with strict contouring, dosimetric, and planning guidelines for gross/clinical/planning target volumes (GTV/CTV/PTV) and organs-at-risk (OAR). We report our experience with BID and QOD EB-APBI with a hypothesis that our treatment planning approach would result in acceptable acute toxicity and cosmesis. We identified patients that received EB-APBI from 4/2017 through 12/2021. Clinical, pathologic, acute toxicity, cosmesis and dosimetric data for the lumpectomy (Lump) GTV/CTV/PTV and key OARs (ipsilateral breast [IB V50%, V80% and V100% of the Rx dose] heart (mean dose, V5% Rx dose;V3 Gy], ipsilateral lung [IL V30% Rx dose] and mean total lung dose [TLD]) were collected. Cosmesis was physician-reported using the 4-point NRG Oncology/RTOG Global Cosmetic Score (GCS): Excellent (E)/Good (G)/Fair (F)/Poor (P). We report descriptive statistics to summarize our results. 245 patients were included with median follow-up 19 months (IQR, 9-30 months): median age, 66 y (IQR, 59-71 y);51% left-sided;82% invasive;100% invasive tumors HR+/HER2-;95% of DCIS HR+;median invasive tumor size 9.5 mm (IQR, 6-13 mm) and DCIS size 8mm (IQR, 4-12 mm);96% nodal surgery in invasive disease. Fractionation was BID in 55%, QOD in 45%. 3DCRT was used in 88% with median 6 fields (IQR, 5-7) and 96% were treated prone. Median Lump PTV eval volume was 176 mL and median breast volume 1335 mL resulting in median breast V50%Rx Dose=40.3% (IQR, 34.5-45.8%) and median breast V100=15.6% (IQR, 10.2-18.6%). Lump PTV coverage was high (median V95=100%). The mean heart dose was 35 cGy (IQR, 15-59 cGy), heart V5%=1.1% (IQR, 0-8.1%), and median heart V3Gy=0% (0-0.5%). The IL V30% (median 0%, IQR 0-0.4%) and TLD (median 49 cGy, IQR 26-93.1 cGy) were also low. The majority of patient had no acute toxicity (55% grade 0 dermatitis;57% grade 0 fatigue;97% grade 0 pruritis). The rate of E/G cosmesis was 97.1% (N=238) and F/P 2.9% (N=7). In patients with at least 2 years follow-up, rates were 96% E/G (N=95) and 4% F/P (N=4). The IB V100 was marginally associated with increased odds of F/P cosmesis (OR=1.18, 95% CI 0.99-1.42, p=0.07). With multiple-field 3DCRT in the prone position, EB-APBI can be delivered with low toxicity and great cosmetic results with BID or QOD treatment. Given the low rate of F/P cosmesis, longer follow-up is needed to confirm stability of these results and to help identify optimal dose-volume parameters to minimize the rate of F/P cosmesis. [ FROM AUTHOR] Copyright of International Journal of Radiation Oncology, Biology, Physics is the property of Pergamon Press - An Imprint of Elsevier Science and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full . (Copyright applies to all s.)

Ambient concentrations and dosimetry of inhaled size-segregated particulate matter during periods of low urban mobility in Bragança, Portugal.

The restrictive measures in place during the COVID-19 pandemic provided a timely scenario to investigate the effects of human activities on air quality, and the extent to which mobility reduction strategies can impact atmospheric pollutant levels. Real-time concentrations of PM1, PM2.5 and PM10 were measured using a mobile platform in a small city of Portugal, during morning and afternoon rush hours, in two distinct phases of the pandemic: emergency phase (cold period, lockdown) and calamity phase (warm period, less restricted). The Multiple-Path Particle Dosimetry Model (MPPD) was used to calculate the PM deposition for adults. Large spatio-temporal variabilities and pronounced changes in mean PM concentrations were observed, with lower concentrations in the calamity phase: PM1 = 2.33 ± 1.61 µg m-3; PM2.5 = 5.15 ± 2.77 µg m-3; PM10 = 23.30 ± 21.53 µg m-3 than in the emergency phase: PM1 = 16.85 ± 31.80 µg m-3; PM2.5 = 30.92 ± 31.93 µg m-3; PM10 = 111.27 ± 104.53 µg m-3. These changes are explained by a combination of meteorological factors and local emissions, mainly residential firewood burning. Regarding regional deposition, PM1 was the main contributor to deposition in the tracheobronchial (5%) and pulmonary (12%) regions, and PM10 in the head region (92%). In general, total deposition doses were higher for males than for females. This work quantitatively demonstrated that even with a 38% reduction in urban mobility during the lockdown, the use of firewood for residential heating is the main contributor to the high concentrations of PM and the respective inhaled dose.

Complementary lessons learned from the testing strategies used for radiation emergencies and COVID-19: A white paper from The International Association of Biological and Electron Paramagnetic Resonance (EPR) Radiation Dosimetry (IABERD)

As COVID-19 emerged, there are parallels between the responses needed for managing SARS-CoV-2 infections and radiation injuries. While some SARS-CoV-2-infected individuals present as asymptomatic, others exhibit a range of symptoms including severe and rapid onset of high-risk indicators of mortality. Similarly, a variety of responses are also observed after a radiological exposure depending on radiation dose, dose heterogeneity, and biological variability. The impact of acute radiation syndrome (ARS) has guided the identification of many biomarkers of radiation exposure, the establishment of medical management strategies, and development of medical countermeasures in the event of a radiation public health emergency. Biodosimetry has a prominent role for identifying exposed persons during a large scale radiological emergency situation. Identifying exposed individuals is also critical in the case of pandemics such as COVID-19, with the additional goal of controlling the spread of disease. Conclusions and significance: IABERD has taken advantage of its competences in biodosimetry to draw lessons from current practices of managing the testing strategy for nuclear accidents to improve responses to SARS-CoV-2. Conversely, lessons learned from managing SARS-CoV-2 can be used to inform best practices in managing radiological situations. Finally, the potential need to deal with testing modalities simultaneously and effectively in both situations is considered.

Appropriateness of radiological diagnostic tests in otolaryngology.

OBJECTIVE: To evaluate the appropriateness of imaging tests associated with radiation in the field of otolaryngology according to the available recommendations, and to estimate the effective radiation dose associated. METHOD: Cross-sectional epidemiological study of the totality of the imaging test requests carried out by two Spanish hospitals (n = 1931). We collected the following information: patient demographic data, type of imaging test, imaging tests referred in the previous 12 months, referrer department and diagnostic suspicion. In accordance with the available guidelines, we considered the requests: (a) Appropriate; (b) Inappropriate; (c) Not adequately justified; (d) Not included in the guidelines. We calculated the prevalence of each category and their variation according to the different variables. Collective and per capita effective dose were calculated for each category. RESULTS: Of the 538 requests, 42% were considered appropriate, 34.4% inappropriate, 11.9% not adequately justified and 11.7% not included in the guidelines. Imaging tests requested by general partitioners (aOR: 0.18; 95% CI: 0.06-0.50) and clinical departments (aOR: 0.27; 95% CI: 0.11-0.60) were less likely to be considered appropriate than those requested by the Otolaryngology department. Patients with a diagnosis suspicion of tumour pathology were more likely to have a requested imaging test classified as appropriate (aOR: 7.12; 95% CI: 3.25-15.61). The cumulative effective dose was 877.8 mSv, of which 40% corresponded to tests classified as inappropriate. CONCLUSIONS: A high percentage of imaging tests are considered as inappropriate in the field of otolaryngology, with a relevant frequency of associated effective radiation dose. Type of department, the diagnostic suspicion and the type of imaging tests were variables associated to the inappropriateness of the test.

A national program for the implementation of lung Stereotactic Ablative Body Radiotherapy (SABR)

Purpose or Objective Following completion of an evaluation program of SABR for primary lung cancer and metachronous extracranial oligometastatic disease, NHS England & NHS Improvement funded a SABR expansion program to increase SABR provision to 50 radiotherapy centres. With reduced access to surgery due to the impact of the COVID-19 pandemic, efforts were focussed on implementing SABR for lung primary and oligometastatic disease in the first instance. Materials and Methods The program consisted of 3 elements, delivered by multi-disciplinary SABR experts from the SABR Consortium and the National Radiotherapy Trials Quality Assurance (RTTQA) Group: Education;Mentorship of RT centres new to SABR by those with extensive experience;QA to ensure the safe and consistent implementation of the technique. A contouring workshop for radiation oncologists was developed by the SABR Consortium Steering Committee. In addition, educational sessions were provided within the SABR Consortium Online Conference, offered free of charge to enable wide access to education and professional development. The Committee produced a Guide for SABR Mentorship, setting out a consistent framework under which mentorship would proceed (Table 1). Mentoring and local protocols followed implementation guidance from the UK SABR Consortium Guidelines. In parallel, RTTQA developed a comprehensive RT QA program (Table 2). Two radiation oncologists and one treatment platform were assessed per hospital. Credentialed clinicians then provided cascade training and education within their departments, formally documenting peer reviews through standard templates provided by RTTQA. (Table Presented) (Table Presented) Results 54 radiation oncologists participated in the contouring workshop. The conference had 1335 registrants, 65% of whom were UK multi-professionals. 15 experienced centres were invited to mentor 24 new SABR sites. Mentors were assigned by equipment for planning and delivery. The mentoring framework was adjusted to accommodate visiting restrictions due to the pandemic and performed remotely through email and video-conferencing instead. The RT QA program commenced in June 2020 with circulation of the facility questionnaire, collecting data on equipment, technique, intention to treat and expected level of mentoring. Responses were used to tailor mentoring and inform what components of the QA program were required for each centre. Contouring submissions were received from 46 radiation oncologists and planning benchmarks were completed by all 24 centres, 22 of which underwent the dosimetry audit. All assessments were reported through standard templates to ensure consistent feedback. Conclusion The implementation of lung SABR was completed in June 2021. Collaboration amongst all stakeholders ensured centres were trained and supported to safely deliver high-quality SABR for lung primary and oligometastatic disease. The education, mentoring and QA program proved effective and has now been rolled out to other oligometastatic sites.

Dose estimation in patients treated with radiotherapy for SARS-COVID disease based on EPID measurement

Introduction. COVID radiotherapy requires performance of all radiotherapy (RT) procedures during one site visit due to the infectious nature of the disease. The aim of the study was to develop methods of estimating the delivered dose based on electronic portal image device (EPID) signal during treatment. Material and methods. Electronic portal image device signal was measured as a function of the phantom dose. The dose in 14 COVID patients was estimated for two X6MV beams. Results. The method allows to estimate dose in phantom with uncertainty of 12%. In this case, a systematic error was reported. Therefore, coefficients for clinical data were calculated and used to determine the dose in patients. The mean difference between the dose calculated and the dose measured for the 14 patients was 1%, but the uncertainty of this method was estimated as ±6% Conclusions. The proposed method may be useful in clinical practice as in vivo method. However, due to high uncertainty, it should be dedicated to the detection of “big” errors.

Preliminary evaluation of 124I labeled virus receptor binding domain

Purpose: Research has shown that ACE2 is one of the important targets of SARS - CoV - 2 virus infection. And receptor binding domain (receptorbindingdomain, RBD), a recombinant spike protein extracted from SARS - CoV - 2 virus, can bind to the angiotensin converting enzyme 2 (ACE2) in human body. This study aims to observe the biodistribution of [124I]I-RBD in mammals, evaluate the ability of [124I]I-RBD to detect ACE2-positive lesions, and explore the potential of RBD against COVID-19. Method: The binding ability of RBD to human ACE2 receptor was studied by surface plasmon resonance (SPR). RBD was labeled with 124I by N-Bromosuccinimide (NBS) mediated method, and high quality radiopharmaceutics [124I]I-RBD were obtained after purification. The binding potency of [124I]I-RBD to human ACE2 was detected by a modified enzyme linked immunosorbent assay (ELISA) method. The biodistribution of [124I]I-RBD in normal BALC/c mice was observed at 0.5 h, 2 h, 24 h and 60 h after tail vein injection. The human radiation dosimetry was estimated based on the animal studies. Results: The labeled [124I] I-RBD was purified by size-exclusion chromatography (PD-10), yielding a radio-chemical purity over 99%, as tested by radio-TLC. Specific activity of the product [124I]I-RBD was 28.9 GBq/nmol, and the radio chemistry purity (RCP) was over in saline for seven days. RBD binds to ACE2 with K<INFD= 14.08 nM, while the binding potency of [124I]I-RBD to ACE2 was calculated as 75.7 nM. Biodistribution data in normal balc/c mice showed that, RBD had a moderate metabolic rate, and its 24-hours-p.i. distribution was basically consistent with the high expression distribution of ACE2 in human body. Human radiation dosimetry estimates an indicated effective dose of 6.42 x 10-2 mSv/MBq. Conclusion: These experimental results confirmed the penitential of 124I-RBD as a novel molecular targeting probe for COVID-19. (Figure Presented) The probing of ACE2 expression via radiolabeled RBD may not only be used for non-invasive ACE2 mapping in mammals, but also have the prospect of radiotherapy to suppress the pandemic of COVID-19 by simply changing the iodine isotopes.

The Impact of COVID-19 on Medical Dosimetry Education: Students' Perception on the Effectiveness of Program's Immediate Response.

In early 2020, many medical dosimetry programs began to offer lectures and clinical rotations remotely in response to COVID-19. Faculty instituted an IRB-approved study to investigate the effectiveness of medical dosimetry educational programs' immediate response to COVID-19 and modifications to teaching practices during the pandemic. The Program Response to COVID-19 Effectiveness Questionnaire (PRCEQ) survey was developed to measure students' perceptions of their learning experience during COVID-19. The subject of the study was the medical dosimetry current and former student population who received modified education delivery during the COVID-19 pandemic. This study suggests that generally students are satisfied with the quality of their virtual didactic and clinical education as well as communication between faculty and students and students to students. Programs should develop strategies to engage students during the virtual classes to motivate them to learn; utilize a variety of formats for the evaluation of students' learning, incorporate activities to help students make connections with real-world clinical situations, and schedule clinical visits for students to learn tasks that require their physical presence in clinic.

Proposal on the use of Xenon-133 against COVID-19.

Since we are able to bring ionizing radiation in the form of a gas cloud to the respiratory system, we have wondered whether Xenon-133 inhalation could be exploited as a treatment option against Covid-19 respiratory virus infections, and urge colleagues in the scientific research community who have the capability to do so to explore the merits of using Xenon-133 in this way to determine whether its usefulness against the Covid-19 virus is indeed genuine.

Use of robotic assistance to reduce proximity and air-sharing during percutaneous cardiovascular intervention.

Aim: Traditional percutaneous cardiovascular interventions require close physical proximity between the patients and the healthcare team, posing occupational hazards that range from radiation exposure to interpersonal air contamination. Materials & methods: Prospective single-arm pilot study (n = 10) to investigate robotic-assisted intervention as a strategy to reduce proximity during the procedure. Primary end point: composite of angiographic success, intervention performed with the team positioned >2 meters from the patient for ≥50% procedure duration, and absence of in-hospital death or acute target lesion occlusion. Results: The composite primary end point was achieved in 100% of cases. Conclusion: Robotic-assisted percutaneous intervention provided successful invasive treatment while reducing proximity and shared air space between the care-delivery team and the patient during the procedure. Trial registration number: NCT04379453 (Clinicaltrials.gov).

Lay abstract Minimally invasive therapies for cardiovascular diseases are techniques that limit the size of incisions needed and so lessen wound healing time, but traditionally require close contact between the patients and the healthcare team. This fact poses hazards that range from radiation exposure to the spread of airborne diseases. We developed a small study of ten patients to investigate whether a new method of robotic-assisted stent implantation for the treatment of a heart attack would reduce proximity between the patient and medical staff during the procedure. To evaluate the effectiveness of that strategy, we assessed the success of the procedure (by analyzing the images of the operation), the amount of time the team was positioned more than 2 meters from the patient and the occurrence of complications during the hospitalization. We concluded that this method of robotic-assisted stent implantation after a heart attack provided successful treatment while reducing proximity and shared air space between the care-delivery team and the patient.

Same day yttrium-90 radioembolization with single photon emission computed tomography/computed tomography: An opportunity to improve care during the COVID-19 pandemic and beyond.

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic has made it more challenging for patients to undergo yttrium-90 (Y-90) radioembolization (RE). Same day Y-90 RE provides an opportunity to minimize logistical challenges and infection risk associated with COVID-19, thus improving patient access. AIM: To describe the use of same day Y-90 RE with routine single photon emission computed tomography/computed tomography (SPECT/CT) in order to optimize therapy. METHODS: All patients were selected for Y-90 RE through a multidisciplinary tumor board, and were screened and tested for COVID-19 infection per institutional protocol. A same day procedure was developed, consisting of angiography, imaging, and Y-90 resin particle delivery. Routine SPECT/CT after technetium-99m macroaggregated albumin (Tc-99m MAA) administration was performed for assessment of arterial supply, personalized dosimetry, and extrahepatic activity. Post-treatment Y-90 bremsstrahlung SPECT/CT was performed for confirmation of particle delivery, by utilization of energy windowing to limit signal from previously administered Tc-99m MAA particles. RESULTS: A total of 14 patients underwent same day Y-90 RE between March and June 2020. Mean lung shunt fraction was 6.13% (range 3.5%-13.1%). Y-90 RE was performed for a single lesion in 7 patients, while the remaining 7 patients had treatment of multifocal lesions. The largest lesion measured 8.3 cm. All patients tolerated the procedure well and were discharged the same day. CONCLUSION: Same day Y-90 RE with resin-based microspheres is feasible, and provides an opportunity to mitigate infection risk and logistical challenges associated with the COVID-19 pandemic and beyond. We recommend consideration of SPECT/CT, especially among patients with complex malignancies, for the potential to improve outcomes and eligibility of patients to undergo same day Y-90 RE.