Evaluation of Radiomics to Predict the Accuracy of Markerless Motion Tracking of Lung Tumors: A Preliminary Study

Template-based matching algorithms are currently being considered for markerless motion tracking of lung tumors. These algorithms use tumor templates derived from the planning CT scan, and track the motion of the tumor on single energy fluoroscopic images obtained at the time of treatment. In cases where bone may obstruct the view of the tumor, dual energy fluoroscopy may be used to enhance soft tissue contrast. The goal of this study is to predict which tumors will have a high degree of accuracy for markerless motion tracking based on radiomic features obtained from the planning CT scan, using peak-to-sidelobe ratio (PSR) as a surrogate of tracking accuracy. In this study, CT imaging data of 8 lung cancer patients were obtained and analyzed through the open source IBEX program to generate 2,287 radiomic features. Agglomerative hierarchical clustering was used to narrow down these features into 145 clusters comprised of the highest correlation to PSR. The features among the clusters with the least inter-correlation were then chosen to limit redundancy in the data. The results of this study demonstrated a number of radiomic features that are positively correlated to PSR. The features with the highest degree of correlation included complexity, orientation and range. This approach may be used to determine patients for whom markerless motion tracking would be beneficial

American Brachytherapy Task Group Report: Adjuvant vaginal brachytherapy for early-stage endometrial cancer: A comprehensive review

This article aims to review the risk stratification of endometrial cancer, treatment rationale, outcomes, treatment planning, and treatment recommendations of vaginal brachytherapy (VBT) in the post-operative management of endometrial cancer patients. The authors performed a thorough review of the literature and reference pertinent articles pertaining to the aims of this review. Adjuvant VBT for early stage endometrial cancer patients results in very low rates of vaginal recurrence (0–3.1%) with low rates of late toxicity which are primarily vaginal in nature. PORTEC-2 supports that VBT results in non-inferior rates of vaginal recurrence compared to external beam radiotherapy (EBRT) for the treatment of high-intermediate risk patients. VBT as a boost following EBRT, in combination with chemotherapy, and for high-risk histologies have shown excellent results as well though randomized data do not exist supporting VBT boost. There are many different applicators, dose-fractionation schedules, and treatment planning techniques which all result in favorable clinical outcomes and low rates of toxicity. Recommendations have been published by the American Brachytherapy Society and the American Society of Radiation Oncology to help guide practitioners in the use of VBT. Data support that patients and physicians both prefer joint decision-making regarding the use of VBT, and patients often desire additional treatment for a marginal benefit in risk of recurrence. Discussions regarding adjuvant therapy for endometrial cancer are best performed in a multi-disciplinary setting and patients should be counseled properly regarding the risks and benefits of adjuvant therapy

Resetting of Central and Peripheral Circadian Oscillators in Aged Rats

The mammalian circadian timing system is affected by aging. Analysis of the suprachiasmatic nucleus (SCN) and of other circadian oscillators reveals age-related changes which are most profound in extra-SCN tissues. Some extra-SCN oscillators appear to stop oscillating in vivo or display altered phase relationships. To determine whether the dynamic behavior of circadian oscillators is also affected by aging we studied the resetting behavior of the Period1 transcriptional rhythm of peripheral and central oscillators in response to a 6 h advance or delay in the light schedule. We employed a transgenic rat with a luciferase reporter to allow for real-time measurements of transcriptional rhythmicity. While phase resetting in the SCN following an advance or a delay of the light cycle appears nearly normal in 2-year-old rats, resynchronization of the liver was seriously disrupted. In addition, the arcuate nucleus and pineal gland exhibited faster resetting in aged rats relative to 4–8-month-old controls. The consequences of these deficits are unknown, but may contribute to organ and brain diseases in the aged as well as the health problems that are common in older shift-workers

ACR Appropriateness Criteria® Cranial Neuropathy: 2022 Update

Cranial neuropathy can result from pathology affecting the nerve fibers at any point and requires imaging of the entire course of the nerve from its nucleus to the end organ in order to identify a cause. MRI with and without intravenous contrast is often the modality of choice with CT playing a complementary role. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer-reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances in which peer-reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation