Rapid predictive dosimetry for radioembolization

Economics of today’s busy clinical practice demand both time and cost-efficient methods of predictive dosimetry for liver radioembolisation. A rapid predictive schema adapted from the Medical Internal Radiation Dose (MIRD) method i.e., Partition Model, has been devised that can be completed within minutes. This rapid schema may guide institutions that do not have access to software capable of comprehensive auto-segmentation of lung, tumour and non-tumorous liver, or where rigorous artery-specific tomographic predictive dosimetry is unfeasible for the routine clinical workflow. This rapid schema is applicable to any beta-emitting radiomicrosphere, although absorbed dose-response thresholds will differ according to device. Sampling errors in lung, tumour and non-tumorous liver will compound and propagate throughout this schema. This rapid schema achieves efficiency in lieu of accuracy. The user must be mindful of potentially large sampling errors and assumes all responsibility. Any suspicion of significant error requires the user to revert back to standard-of-care methods

First Strike personalized predictive radioiodine prescription for inoperable metastatic differentiated thyroid cancer

Objective(s): The traditional practice of empiric radioiodine (I-131) prescription is scientifically obsolete and inappropriate for inoperable metastatic differentiated thyroid cancer. However, theranostically guided prescription is still years away for many institutions. A personalized predictive method of radioiodine prescription that bridges the gap between empiric and theranostic methods is presented. It is an adaptation of the “maximum tolerated activity” method, where serial blood sampling is replaced by population kinetics carefully chosen by the user. It aims to maximize crossfire benefits within safety constraints to overcome tumour absorbed dose heterogeneity for a safe and effective first radioiodine fraction i.e., the First Strike.Methods: The EANM method of blood dosimetry was incorporated with population kinetics, marrow and lung safety constraints, body habitus and clinical assessment of metastatic extent. Population data of whole body and blood kinetics in patients with and without metastases, prepared by recombinant human thyroid stimulating hormone or thyroid hormone withdrawal, and the maximum safe marrow dose rate were deduced from published data. For diffuse lung metastases, the lung safety limit was linearly scaled by height and separated into lung and remainder-of-body components.Results: The slowest whole body Time Integrated Activity Coefficient (TIAC) amongst patients with any metastases was 33.5±17.0 h and the highest percentage of whole body TIAC attributed to blood was 16.6±7.9%, prepared by thyroid hormone withdrawal. A variety of other average radioiodine kinetics is tabulated. Maximum safe marrow dose rate was deduced to be 0.265 Gy/h per fraction, where blood TIAC is normalised to administered activity. An easy-to-use calculator was developed which only requires height, weight and gender to populate recommendations for personalized First Strike prescription. The user decides by clinical gestalt whether the prescription is to be constrained by marrow or lung, then selects an activity depending on how extensive the metastases are likely to be. A Standard Female with oligometastasis and good urine output without diffuse lung metastasis is expected to safely tolerate 8.03 GBq of radioiodine as the First Strike.Conclusion: This predictive method will help institutions rationalise the First Strike prescription based on radiobiologically sound principles, personalised to individual circumstances

Rapid predictive dosimetry for Second Strike prescription based on whole body radioiodine kinetics in differentiated thyroid cancer

Objective(s): In systemic radionuclide therapy such as radioiodine (I-131) for differentiated thyroid cancer, post-therapy dosimetry is essential to verify pre-therapy predictions, which in turn informs the next treatment. However, post-therapy multi-time point dosimetry is resource intensive and unfeasible in many institutions. We devised a schema of rapid predictive dosimetry by circumventing post-First Strike multi-time point dosimetry with carefully assigned gestalt values of predicted kinetics to personalise the Second Strike prescription.Methods: Verification is performed after the First Strike. Patient-specific time-activity curve is plotted from serial measurements of whole body exposure rates to obtain its decay constant; its inverse is the whole body Time Integrated Activity Coefficient (TIAC). The percentage of whole body TIAC attributed to blood is carefully assigned by gestalt based on population kinetics tabulated in Part 1, adjusted by any metastasis on I-131 whole body scintigraphy. Marrow absorbed dose is calculated by EANM formularism. Lung safety threshold at 48h post-therapy is linearly scaled by height, where the patient’s risk of lung radiotoxicity is revealed from the whole body time-activity curve value at 48h. Predictive prescription for the second I-131 fraction (Second Strike) is by careful gestalt assessment based on predicted kinetics, remaining marrow and lung tolerance, marrow dose rate constraint per fraction (0.265 Gy/h), local regulatory and facility requirements in relation to radiation protection. Tumour dosimetry is obviated under the assumption of severe tumour absorbed dose heterogeneity. The final prescription for the Second Strike is usually the lowest I-131 activity amongst all clinical, dosimetric and regulatory constraints.Results: This schema is incorporated into a Predictive Calculator spreadsheet for rapid predictive dosimetry, and is freely available. Calculations may be completed within minutes to generate personalised predictive prescriptions, making it feasible for routine clinical implementation.Conclusion: Our innovative schema of rapid verification and predictive dosimetry bridges the technological gap between empiric vs theranostic prescription to help institutions modernise. Its expeditious design makes this schema feasible to be integrated into the routine clinical workflow. Its predictive estimates provide invaluable dosimetric insight to inform the next I-131 fraction, allowing every prescription to be scientifically rationalised and personalised according to individual circumstances

Crowdsourcing Detection of Sampling Biases in Image Datasets

Despite many exciting innovations in computer vision, recent studies reveal a number of risks in existing computer vision systems, suggesting results of such systems may be unfair and untrustworthy. Many of these risks can be partly attributed to the use of a training image dataset that exhibits sampling biases and thus does not accurately reflect the real visual world. Being able to detect potential sampling biases in the visual dataset prior to model development is thus essential for mitigating the fairness and trustworthy concerns in computer vision. In this paper, we propose a three-step crowdsourcing workflow to get humans into the loop for facilitating bias discovery in image datasets. Through two sets of evaluation studies, we find that the proposed workflow can effectively organize the crowd to detect sampling biases in both datasets that are artificially created with designed biases and real-world image datasets that are widely used in computer vision research and system development

Observing Human Mobility Internationally During COVID-19

This article analyzes visual data captured from five countries and three U.S. states to evaluate the effectiveness of lockdown policies for reducing the spread of COVID-19. The main challenge is the scale: nearly six million images are analyzed to observe how people respond to the policy changes

Corrigendum to “An Emerging Translational Model to Screen Potential Medicinal Plants for Nephrolithiasis, an Independent Risk Factor for Chronic Kidney Disease”

Pharmacological therapy for urolithiasis using medicinal plants has been increasingly adopted for the prevention of its recurrence. A Drosophila melanogaster model developed for translational research of urolithiasis was applied to evaluate agents with potential antilithic effects and calcium oxalate (CaOx) formation. Potential antilithic herbs were prepared in a mixture of food in a diluted concentration of 5,000 from the original extract with 0.5% ethylene glycol (EG) as the lithogenic agent. The control group was fed with food only. After 3 weeks, flies (n≥150 for each group) were killed using CO2 narcotization, and the Malpighian tubules were dissected, removed, and processed for polarized light microscopy examination of the crystals. The crystal formation rate in the EG group was 100.0%. In the study, 16 tested herbal drugs reached the crystal formation rate of 0.0%, including Salviae miltiorrhizae, Paeonia lactiflora, and Carthami flos. Scutellaria baicalensis enhanced CaOx crystal formation. Two herbal drugs Commiphora molmol and Natrii sulfas caused the death of all flies. Our rapid screening methods provided evidence that some medicinal plants have potential antilithic effects. These useful medicinal plants can be further studied using other animal or human models to verify their effects