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This article aims to compare the dosimetric performance between knowledge-based plan (KBP) libraries with and without trade-off (TO) exploration using multicriterial optimization (MCO) for tongue cancer patients. The trade-off optimized library (KBP&#95;MCO) contains a minimal number of constituent plans, whereas two nontrade-off optimized libraries contain a minimal and a large number of treatment plans, respectively. Three KBP libraries were created: KBP&#95;100 and KBP&#95;20, each comprising of 100 and 20 manually optimized plans, respectively. Additionally, another KBP library (KBP&#95;MCO&#95;20) was created by reoptimizing the constituent plans from KBP&#95;20 using MCO techniques. A total of 70 tongue plans were validated through these libraries. Validation plans were evaluated for PTV and organ at risk (OAR) doses. Greenhouse-Geisser analysis (ANOVA) and the Bonferroni procedure (t-test) were used for statistical evaluation. The mean PTVD95% for KBP&#95;100, KBP&#95;20, and KBP&#95;MCO&#95;20 was 98.4% ± 0.3%, 98.9% ± 0.2%, and 98.7% ± 0.2%, respectively. The statistical significance of PTVD95% for the 3 possible combinations-KBP&#95;100 vs KBP&#95;20, KBP&#95;100 vs KBP&#95;MCO&#95;20, and KBP&#95;20 vs KBP&#95;MCO&#95;20 were statistically significant with p < 0.001. Spinal cord doses for KBP&#95;100, KBP&#95;20, and KBP&#95;MCO&#95;20 were 29.6 ± 1.8 Gy, 31.2 ± 2.5 Gy, and 26.8 ± 1.9 Gy, respectively, with p(KBP&#95;100 vs KBP&#95;20) = 0.14, p(KBP&#95;100 vs KBP&#95;MCO&#95;20) = 0.001, and p(KBP&#95;20 vs KBP&#95;MCO&#95;20) < 0.001. Only the first comparison showed a statistically insignificant variation. A trade-off optimized plan library with a minimal number of patients (20) yields better performance for serial structures (spinal cord and brainstem) compared to large manually optimized KBP libraries. For other organs at risk (OARs) and target dose coverage, although statistical differences were significant in most instances, the differences in physical dose were small and probably will not yield any significant clinical differences., Competing Interests: Conflicts of Interest None., (Copyright © 2024 American Association of Medical Dosimetrists. Published by Elsevier Inc. All rights reserved.)

This study assesses the dosimetric effectiveness of the commercial trade-off optimization (TO) module in comparison to iterative optimization for volumetric modulated arc therapy (VMAT) in craniospinal irradiation technique.Fifteen patients who had previously undergone VMAT-based craniospinal irradiation (CSI) using manual optimization (TP) underwent re-optimization with trade-off optimization (MCO). All patients were treated using the Halcyon-E O-ring linear accelerator, with maximum field size of 28×28 cm², a 6MV unflattened beam, and adjacent isocenter field overlap of 10 cm. Plans were compared based on PTV dose coverage (D95%), maximum dose (Dmax), conformity index (CI), heterogeneity index (HI), maximum and mean dose to serial and parallel organs, respectively. Statistical evaluation was conducted using paired sample t-tests. The PTVD95% for TO and MCO plans were 98.0% ± 1.0% and 97.4% ± 0.7%, respectively. In the same sequence, HIs were 1.06 ± 0.01 and 1.07 ± 0.01. CIs for both arms were 0.9 ± 0.0 and its variation was statistically significant (p = 0.027). The differences in dose for bilateral cochlea and left optic nerves were statistically significant (0.022≤ p ≤0.049). The ΔDmax for serial organs and mean dose for parallel organs did not exceed 1%, except for the bilateral optic nerve, mandible, oral cavity, right parotid, and stomach. No parallel organ showed a statistically significant dose variation. Clinically significant reductions in dose were noted for three organs; the average dose reduction in MCO plans for bilateral optic nerves was 3.9%, and for the larynx, it was 8.5%. In this study, trade-off optimization did not demonstrate any significant improvement over the iteratively optimized plans, primarily because the planners were highly skilled and could already generate high-quality plans using iterative optimization alone. However, this finding may not necessarily apply universally to all treatment planners or clinical settings., (Copyright © 2024 American Association of Medical Dosimetrists. Published by Elsevier Inc. All rights reserved.)

RaySearch Laboratories is a world leader in the field of advanced software and creator of the RayStation treatment planning system for radiation therapy. The aim with RayStation is to deliver an unmatched user experience and leading functionality. Unique features described here include multiatlas based autosegmentation for contouring, deformable registration with 2 different algorithms, multicriteria optimization, Plan Explorer, fallback planning, ultrafast computation speed, and 4-dimensional (4D) adaptive radiation therapy. RayStation can be used to plan for electrons and photons on traditional linacs, for protons on various delivery systems, and for Accuray's helical TomoTherapy system. This paper describes some of these modalities, with reference to clinical cases and including descriptions of the impact on workflow., (Copyright © 2018 American Association of Medical Dosimetrists. Published by Elsevier Inc. All rights reserved.)

Efficacy of inverse planning is becoming increasingly important for advanced radiotherapy techniques. This study's aims were to validate multicriteria optimization (MCO) in RayStation (v2.4, RaySearch Laboratories, Sweden) against standard intensity-modulated radiation therapy (IMRT) optimization in Oncentra (v4.1, Nucletron BV, the Netherlands) and characterize dose differences due to conversion of navigated MCO plans into deliverable multileaf collimator apertures. Step-and-shoot IMRT plans were created for 10 patients with localized prostate cancer using both standard optimization and MCO. Acceptable standard IMRT plans with minimal average rectal dose were chosen for comparison with deliverable MCO plans. The trade-off was, for the MCO plans, managed through a user interface that permits continuous navigation between fluence-based plans. Navigated MCO plans were made deliverable at incremental steps along a trajectory between maximal target homogeneity and maximal rectal sparing. Dosimetric differences between navigated and deliverable MCO plans were also quantified. MCO plans, chosen as acceptable under navigated and deliverable conditions resulted in similar rectal sparing compared with standard optimization (33.7 ± 1.8 Gy vs 35.5 ± 4.2 Gy, p = 0.117). The dose differences between navigated and deliverable MCO plans increased as higher priority was placed on rectal avoidance. If the best possible deliverable MCO was chosen, a significant reduction in rectal dose was observed in comparison with standard optimization (30.6 ± 1.4 Gy vs 35.5 ± 4.2 Gy, p = 0.047). Improvements were, however, to some extent, at the expense of less conformal dose distributions, which resulted in significantly higher doses to the bladder for 2 of the 3 tolerance levels. In conclusion, similar IMRT plans can be created for patients with prostate cancer using MCO compared with standard optimization. Limitations exist within MCO regarding conversion of navigated plans to deliverable apertures, particularly for plans that emphasize avoidance of critical structures. Minimizing these differences would result in better quality treatments for patients with prostate cancer who were treated with radiotherapy using MCO plans., (Copyright © 2014 American Association of Medical Dosimetrists. Published by Elsevier Inc. All rights reserved.)

Background: Previously published studies reported an increased risk of gastrointestinal illness in the 14 days following trivalent influenza vaccination (TIV) in young children. While gastrointestinal illness may be a true adverse effect of TIV, other factors may influence this observed association, such as seasonal illness patterns and children being exposed to gastrointestinal pathogens at medical visits. The objective of this study was to examine factors influencing the association between TIV and gastrointestinal illness. Specifically, using data from a previous influenza vaccine safety study, we examined the association between medical encounters without TIV and gastrointestinal illness., Methods: Using electronic health record (EHR) data from 6 managed care organizations (MCOs), we identified medically attended gastrointestinal illness cases among children 24-59 months in the 2002-2006 influenza seasons. We matched each case to four controls on sex, birthdate (month/year), MCO, influenza season, and presence of a chronic condition. We then looked 1-14 days prior to the index date (gastrointestinal illness diagnosis date) to determine whether the child had a medical encounter. We excluded previous medical encounters with gastrointestinal-related diagnoses or TIV. Conditional logistic regression was used to calculate odds ratios and 95% confidence intervals., Results: We identified 2062 gastrointestinal illness cases and matched them to 8248 controls. We observed increased odds of gastrointestinal illness within 14 days after a medical encounter (odds ratio=1.9; 95% confidence interval [CI]: 1.7-2.2) among children without chronic conditions. Among children with chronic conditions, the odds ratio was 3.9 (95% CI: 2.5-6.2)., Conclusions: We demonstrated that another exposure related to vaccination, medical visits, is also associated with increased odds for gastrointestinal illness. This study highlights challenges of interpreting results from observational vaccine safety studies when there are co-occurring exposures, and the importance of investigating confounding in EHR data, which are an essential resource for vaccine safety research., (Copyright © 2013 Elsevier Ltd. All rights reserved.)