Equity in practice: Assigning competence to shape STEM student participation.

Improving equity in undergraduate STEM is a national imperative. Although there is a rapidly growing body of research in this area, there is still a need to generate empirical evidence for equitable teaching techniques. We ground our work in Complex Instruction, an extensively researched pedagogical approach based on sociological theories and the malleability of status. This approach has been applied primarily in K-12 classrooms. In this manuscript, we explore the application of one strategy from Complex Instruction-assigning competence-to undergraduate STEM classrooms. We provide an analysis of three instructors' implementation of assigning competence and track the impact on student participation. This work makes a unique contribution to the field, as the first study that directly documents changes in student participation resulting from assigning competence in undergraduate STEM.

A Pandemic Crash Course: Learning to Teach Equitably in Synchronous Online Classes.

This article describes an equity-focused professional learning community that used the EQUIP observation protocol to provide data analytics to instructors. The learning community met during Spring 2020, and due to the global coronavirus pandemic, it moved online midsemester. This article describes patterns of student participation and how they were impacted in moving online. We found that student participation dropped significantly in moving online, but instructors were able to implement new teaching strategies to increase participation. We document seven concrete strategies that instructors used to promote equitable participation in their online classes and that can be incorporated by biology educators into their online teaching. The strategies were: 1) re-establishing norms, 2) using student names, 3) using breakout rooms, 4) leveraging chat-based participation, 5) using polling software, 6) creating an inclusive curriculum, and 7) cutting content to maintain rigor. In addition, we describe the faculty learning process and how EQUIP data and the learning community environment supported instructors to change their practices.

Clinical workflow for MR-only simulation and planning in prostate.

PURPOSE: To describe the details and experience of implementing a MR-only workflow in the clinic for simulation and planning of prostate cancer patients. METHODS: Forty-eight prostate cancer patients from June 2016 - Dec 2016 receiving external beam radiotherapy were scheduled to undergo MR-only simulation. MR images were acquired for contouring (T2w axial, coronal, sagittal), synthetic-CT generation (3D FFE-based) and fiducial identification (3D bFFE-based). The total acquisition time was 25 min. Syn-CT was generated at the console using commercial software called MRCAT. As part of acceptance testing of the MRCAT package, external laser positioning system QA (< 2 mm) and geometric fidelity QA (< 2 mm within 50 cm LR and 30 cm AP) were performed and baseline values were set. Our current combined CT + MR simulation process was modified to accommodate a MRCAT-based MR-only simulation workflow. An automated step-by-step process using a MIM™ workflow was created for contouring on the MR images. Patient setup for treatment was achieved by matching the MRCAT DRRs with the orthogonal KV radiographs based on either fiducial ROIs or bones. 3-D CBCTs were acquired and compared with the MR/syn-CT to assess the rectum and bladder filling compared to simulation conditions. RESULTS: Forty-two patients successfully underwent MR-only simulation and met all of our institutional dosimetric objectives that were developed based on a CT + MR-based workflow. The remaining six patients either had a hip prosthesis or their large body size fell outside of the geometric fidelity QA criteria and thus they were not candidates for MR-only simulation. A total time saving of ~15 min was achieved with MR-based simulation as compared to CT + MR-based simulation. An automated and organized MIM workflow made contouring on MR much easier, quicker and more accurate compared with combined CT + MR images because the temporal variations in normal structure was minimal. 2D and 3D treatment setup localization based on bones/fiducials using a MRCAT reference image was successfully achieved for all cases. CONCLUSIONS: MR-only simulation and planning with equivalent or superior target delineation, planning and treatment setup localization accuracy is feasible in a clinical setting. Future work will focus on implementing a robust 3D isotropic acquisition for contouring.

Measurement of the internal diameter of plastic tubes from projection MR images using a model-based least-squares fit approach.

Hyperpolarized (HP) 3He MRI is an emerging tool in the diagnosis and evaluation of pulmonary diseases involving bronchoconstriction, such as asthma. Previously, airway diameters from dynamic HP 3He MR images of the lung were assessed manually and subjectively, and were thus prone to uncertainties associated with human error and partial volume effects. A model-based algorithm capable of fully utilizing pixel intensity profile information and attaining subpixel resolution has been developed to measure surrogate airway diameters from HP 3He MR static projection images of plastic tubes. This goal was achieved by fitting ideal pixel intensity profiles for various diameter (6.4 to 19.1 mm) circular tubes to actual pixel intensity data. A phantom was constructed from plastic tubes of various diameters connected in series and filled with water mixed with contrast agent. Projection MR images were then taken of the phantom. The favorable performance of the model-based algorithm compared to manual assessment demonstrates the viability of our approach. The manual and algorithm approaches yielded diameter measurements that generally stayed within 1 x the pixel dimension. However, inconsistency of the manual approach can be observed from the larger standard deviations of its measured values. The method was then extended to HP 3He MRI, producing encouraging results at tube diameters characteristic of airways beyond the second generation, thereby justifying their application to lung airway imaging and measurement. Potential obstacles when measuring airway diameters using this method are discussed.

Distribution of hyperpolarized xenon in the brain following sensory stimulation: preliminary MRI findings.

In hyperpolarized xenon magnetic resonance imaging (HP (129)Xe MRI), the inhaled spin-1/2 isotope of xenon gas is used to generate the MR signal. Because hyperpolarized xenon is an MR signal source with properties very different from those generated from water-protons, HP (129)Xe MRI may yield structural and functional information not detectable by conventional proton-based MRI methods. Here we demonstrate the differential distribution of HP (129)Xe in the cerebral cortex of the rat following a pain stimulus evoked in the animal's forepaw. Areas of higher HP (129)Xe signal corresponded to those areas previously demonstrated by conventional functional MRI (fMRI) methods as being activated by a forepaw pain stimulus. The percent increase in HP (129)Xe signal over baseline was 13-28%, and was detectable with a single set of pre and post stimulus images. Recent innovations in the production of highly polarized (129)Xe should make feasible the emergence of HP (129)Xe MRI as a viable adjunct method to conventional MRI for the study of brain function and disease.

Partial breast brachytherapy as the primary treatment for breast cancer diagnosed after mantle radiation therapy for Hodgkin's disease.

PURPOSE: Mastectomy is the most widely accepted treatment for managing breast cancer in patients who have previously received mantle radiation therapy (RT). With accumulating evidence supporting partial breast irradiation, we treated newly diagnosed breast cancer among lymphoma survivors who had history of RT with lumpectomy and breast brachytherapy. METHODS: Five patients, with history of Hodgkin disease (HD) underwent lumpectomy and sentinel lymphadenectomy +/- axillary dissection followed by low dose rate Ir-192 interstitial brachytherapy. A multicatheter technique was used and all patients received 45 Gy to the target volume over 4 to 5 day time interval. Adjuvant systemic therapy when indicated was administered after completion of brachytherapy. RESULTS: The median time from the treatment of the HD to the diagnosis of breast cancer was 242 months (range: 68-322 months). The median T-size of the invasive breast cancer is 0.7 cm. The range of follow up after brachytherapy is 5 to 67 months. All 5 patients have an intact breast and are without evidence of relapse. No patients developed an infection. No skin toxicity > or =grade 2 was observed. All patients have an excellent cosmetic result. No excessive fibrosis or necrosis has been observed. CONCLUSION: The preliminary experience using partial breast brachytherapy (PBB) in patients with previous history of mantle RT suggests low complication rates, and acceptable cosmetic results. The excellent local control and freedom from mastectomy for local recurrence warrants further investigation to establish brachytherapy as an acceptable alternative to mastectomy for early stage breast cancer among HD survivors with history of prior RT.

Comparison of airway diameter measurements from an anthropomorphic airway tree phantom using hyperpolarized 3He MRI and high-resolution computed tomography.

An anthropomorphic airway tree phantom was imaged with both hyperpolarized (HP) 3He MRI using a dynamic projection scan and computed tomography (CT). Airway diameter measurements from the HP 3He MR images obtained using a newly developed model-based algorithm were compared against their corresponding CT values quantified with a well-established method. Of the 45 airway segments that could be evaluated with CT, only 14 airway segments (31%) could be evaluated using HP 3He MRI. No airway segments smaller than approximately 4 mm in diameter and distal to the fourth generation were adequate for analysis in MRI. For the 14 airway segments measured, only two airway segments yielded a non-equivalent comparison between the two imaging modalities, while eight more had inconclusive comparison results, leaving only four airway segments (29%) that satisfied the designed equivalence criteria. Some of the potential problems in airway diameter quantification described in the formulation of the model-based algorithm were observed in this study. These results suggest that dynamic projection HP 3He MRI may have limited utility for measuring airway segment diameters, particularly those of the central airways.