Stakeholders' perspectives on transplant metrics: the 2022 Scientific Registry of Transplant Recipients' consensus conference.

In July 2022, the Scientific Registry of Transplant Recipients (SRTR) hosted an innovative, multistakeholder consensus conference to identify information and metrics desired by stakeholders in the transplantation system, including patients, living donors, caregivers, deceased donor family members, transplant professionals, organ procurement organization professionals, payers, and regulators. Crucially, patients, caregivers, living donors, and deceased donor family members were included in all aspects of this conference, including serving on the planning committee, participating in preconference focus groups and learning sessions, speaking at the conference, moderating conference sessions and breakout groups, and shaping the conclusions. Patients constituted 24% of the meeting participants. In this report, we document the proceedings and enumerate 160 recommendations, 10 of which have been highly prioritized. SRTR will use the recommendations to develop new presentations of information and metrics requested by stakeholders to support informed decision-making.

Variation in adult living donor liver transplantation in the United States: Identifying opportunities for increased utilization.

In the United States, living donor liver transplantation (LDLT) is limited to transplant centers with specific experience. However, the impact of recipient characteristics on procedure selection (LDLT vs. deceased donor liver transplant [DDLT]) within these centers has not been described. Transplant registry data for centers that performed ≥1 LDLT in 2002-2019 were analyzed using hierarchal regression modeling to quantify the impact of patient and center factors on the adjusted odds ratio (aOR) of LDLT (vs DDLT). Among 73,681 adult recipients, only 4% underwent LDLT, varying from <1% to >60% of total liver transplants. After risk adjustment, the likelihood of receiving an LDLT rose by 73% in recent years (aOR 1.73 for 2014-2019 vs. 2002-2007) but remained lower for older adults, men, racial and ethnic minorities, and obese patients. LDLT was less commonly used in patients with hepatocellular carcinoma or alcoholic cirrhosis, and more frequently in those with hepatitis C and with lower severity of illness (Model for End-Stage Liver Disease (MELD) score < 15). Patients with public insurance, lower educational achievement, and residence in the Northwest and Southeast had decreased access. While some differences in access to LDLT reflect clinical factors, further exploration into disparities in LDLT utilization based on center practice and socioeconomic determinants of health is needed.

Living donor liver transplantation: A multi-disciplinary collaboration towards growth, consensus, and a change in culture.

INTRODUCTION: Living donor liver transplantation (LDLT) reduces liver transplant waitlist mortality and provides excellent long-term outcomes for persons with end stage liver disease. Yet, utilization of LDLT has been limited in the United States (US). METHODS: In October 2021, the American Society of Transplantation held a consensus conference to identify important barriers to broader expansion of LDLT in the US, including data gaps, and make recommendations for impactful and feasible mitigation strategies to overcome these barriers. Domains addressed encompassed the entirety of the LDLT process. Representation from international centers and living donor kidney transplantation were included for their perspective/experience in addition to members across disciplines within the US liver transplantation community. A modified Delphi approach was employed as the consensus methodology. RESULTS: The predominant theme permeating discussion and polling results centered on culture; the beliefs and behaviors of a group of people perpetuated over time. CONCLUSIONS: Creating a culture of support for LDLT in the US is key for expansion and includes engagement and education of stakeholders across the spectrum of the process of LDLT. A shift from awareness of LDLT to acknowledgement of benefit of LDLT is the primary goal. Propagation of the maxim "LDLT is the best option" is pivotal.

A survey of transplant providers regarding attitudes, barriers, and facilitators to living donor liver transplantation in the United States.

INTRODUCTION: A successful living donor liver transplant (LDLT) is the culmination of a multifaceted process coordinated among key stakeholders. METHODS: We conducted an electronic survey of US liver transplant (LT) centers (August 26, 2021-October 10, 2021) regarding attitudes, barriers, and facilitators of LDLT to learn how to expand LDLT safely and effectively in preparation for the American Society of Transplantation Living Donor Liver Transplant Consensus Conference. RESULTS: Responses were received from staff at 58 programs (40.1% of US LT centers). There is interest in broadening LDLT (100% of LDLT centers, 66.7% of non-LDLT centers) with high level of agreement that LDLT mitigates donor shortage (93.3% of respondents) and that it should be offered to all suitable candidates (87.5% of respondents), though LDLT was less often endorsed as the best first option (29.5% of respondents). Key barriers at non-LDLT centers were institutional factors and surgical expertise, whereas those at LDLT centers focused on waitlist candidate and donor factors. Heterogeneity in candidate selection for LDLT, candidate reluctance to pursue LDLT, high donor exclusion rate, and disparities in access were important barriers. CONCLUSION: Findings from this study may help guide current and future expansion of LDLT more efficiently in the US. These efforts require clear and cohesive messaging regarding LDLT benefits, engagement of the public community, and dedicated resources to equitably increase LDLT access.

Degree of leukochimerism with calf age in Angus-crossbred twin sets.

Twinning in cattle is infrequent and usually undesired. It can result in an increased occurrence of abortion and dystocia, reduced calf survival and a high likelihood of freemartinism in mixed-sex twins. Twin gestations are also commonly associated with the formation of placental vascular anastomoses (PVA) between twins. Through PVA they share blood, hormones (leading to freemartinism in mixed sex twins) and hematopoietic stem cells, which are the progenitors of white blood cells. The sharing of stem cells between twins can result in leukochimeric twin sets. These are twins that have white blood cells derived from both self and the co-twin owing to the fetal migration of hematopoietic stem cells from the extraembryonic mesoderm of the yolk sac to final sites like bone marrow and thymus. This study examined the degree to which this leukochimerism changes with age. DNA was extracted from hair bulbs containing mesenchymal dermal papilla to determine the individual's true genotype and blood samples were obtained at six time points from 1 week to 8 months of age to assess leukochimerism. Samples were genotyped using a medium density SNP chip, and quantitative estimates of allele frequency were determined using SNPs for which members of a twin set had alternative homozygous genotypes. The results indicate statistically significant changes in the proportion of self and co-twin with age and suggest that by 2-4 months of age the genotypic mix in white blood cells represents the hematopoetic stem cell population resident in the individual (i.e. permanently found in thymus and bone marrow).

Effects of Diabetes on Bone Material Properties.

PURPOSE OF REVIEW: Individuals with type 1 and type 2 diabetes mellitus (T1DM, T2DM) have an increased risk of bone fracture compared to non-diabetic controls that is not explained by differences in BMD, BMI, or falls. Thus, bone tissue fracture resistance may be reduced in individuals with DM. The purpose of this review is to summarize work that analyzes the effects of T1DM and T2DM on bone tissue compositional and mechanical properties. RECENT FINDINGS: Studies of clinical T2DM specimens revealed increased mineralization and advanced glycation endproduct (AGE) concentrations and significant relationships between mechanical performance and composition of cancellous bone. Specifically, in femoral cancellous tissue, compressive stiffness and strength increased with mineral content; and post-yield properties decreased with AGE concentration. In addition, cortical resistance to in vivo indentation (bone material strength index) was lower in patients with T2DM vs. age-matched non-diabetic controls, and this resistance decreased with worsening glycemic control. Recent studies on patients with T1DM and history of a prior fragility fracture found greater mineral content and concentrations of AGEs in iliac trabecular bone and correspondingly stiffer, harder bone at the nanosacle. Recent observational data showed greater AGE and mineral content in surgically retrieved bone from patients with T2DM vs. non-DM controls, consistent with reduced bone remodeling. Limited data on human T1DM bone tissue also showed higher mineral and AGE content in patients with prior fragility fractures compared to non-DM and non-fracture controls.

Social cognitive predictors of engineering students' academic persistence intentions, satisfaction, and engagement.

The demand for high quality engineers is of particular importance as engineering jobs are projected to grow in the next 10 years (United States Bureau of Labor Statistics, 2018). More work is needed to understand factors related to academic engagement, satisfaction, and persistence intentions of Latino/as and women in engineering: 2 underrepresented groups in the engineering pipeline. We present findings that explored the role of social-cognitive, environmental, and personality variables in engineering persistence intentions, engagement and satisfaction of a diverse sample of 1,335 engineering students using an extension of the integrative social cognitive career theory model (SCCT; Lent et al., 2013). Results indicated that (a) the hypothesized model fit the data well for the full sample and across 8 subsamples based on gender-ethnicity (i.e., Latinas, Latinos, White women, and White men) and ethnicity-school type (i.e., Latina/os at Hispanic-serving institutions [HSIs], Latina/os at predominantly White institutions [PWIs], Whites at HSIs, and Whites at PWIs), (b) all but 5 model parameters were significant and positive for the full sample, (c) a subset of model parameters differed by the interactions of race/ethnicity-gender and race/ethnicity-school type groups, and (d) the relations within the model explained a significant amount of variance in engineering academic engagement, satisfaction, and persistence intentions for the full sample and 8 subsamples. Implications of the findings for educational and career interventions aimed at retaining Latina/os and women in engineering are discussed in relation to building on social cognitions in engineering academic engagement, satisfaction, and persistence intentions. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Antimicrobial Coatings for Food Contact Surfaces: Legal Framework, Mechanical Properties, and Potential Applications.

Food contact surfaces (FCS) in food processing facilities may become contaminated with a number of unwanted microorganisms, such as Listeria monocytogenes, Escherichia coli O157:H7, and Staphylococcus aureus. To reduce contamination and the spread of disease, these surfaces may be treated with sanitizers or have active antimicrobial components adhered to them. Although significant efforts have been devoted to the development of coatings that improve the antimicrobial effectiveness of FCS, other important coating considerations, such as hardness, adhesion to a substrate, and migration of the antimicrobial substance into the food matrix, have largely been disregarded to the detriment of their translation into practical application. To address this gap, this review examines the mechanical properties of antimicrobial coatings (AMC) applied to FCS and their interplay with their antimicrobial properties within the framework of relevant regulatory constraints that would apply if these were used in real-world applications. This review also explores the various assessment techniques for examining these properties, the effects of the deposition methods on coating properties, and the potential applications of such coatings for FCS. Overall, this review attempts to provide a holistic perspective. Evaluation of the current literature urges a compromise between antimicrobial effectiveness and mechanical stability in order to adhere to various regulatory frameworks as the next step toward improving the industrial feasibility of AMC for FCS applications.

Balancing Academic Rigor and Creative Thinking: A Transformational Approach to Teaching Senior Design.

Innovation arises from creativity. "Thinking outside the box" has long been seen as a necessary precursor to innovation and invention in engineering. However, creativity is rarely part of traditional engineering curricula. In 2015, our group began to explore integrating theater-based creativity methods into bioengineering capstone design. Evaluation of student outcomes was encouraging, so we continued to develop the course in 2016 and 2017. As we worked to refine the pedagogical process, we discovered tensions (real or perceived) between providing academic rigor and allowing students to embrace their creativity; for instance, we experienced some resistance from engineering faculty and students toward adopting methods they viewed as "artsy" or lacking academic rigor. Here, we discuss the tensions we observed offer potential ways to mitigate such tensions and begin to consider how to expand on our successes.

Ultrasonic modulation of tissue optical properties in ex vivo porcine skin to improve transmitted transdermal laser intensity.

BACKGROUND AND OBJECTIVE: Applications of light-based energy devices involving optical targets within the dermis frequently experience negative side-effects resultant from surface scattering and excess optical absorption by epidermal melanin. As a broadband optical absorber, melanin decreases the efficacy of light-based treatments throughout the ultraviolet, visible, and near-infrared spectra while also generating additional heat within the surface tissue that can lead to inflammation or tissue damage. Consequently, procedures may be performed using greater energy densities to ensure that the target receives a clinically relevant dose of light; however, such practices are limited, as doing so tends to exacerbate the detrimental complications resulting from melanin absorption of treatment light. The technique presented herein represents an alternative method of operation aimed at increasing epidermal energy fluence while mitigating excess absorption by unintended chromophores. The approach involves the application of continuously pulsed ultrasound to modulate the tissue's optical properties and thereby improve light transmission through the epidermis. MATERIALS AND METHODS: To demonstrate the change in optical properties, pulsed light at a wavelength of 532 nm from a Q-switched Nd:YAG laser was transmitted into 4 mm thick samples of porcine skin, comprised of both epidermal and dermal tissue. The light was transmitted using an optical waveguide, which allowed for an ultrasonic transducer to be incorporated for simultaneous paraxial pulsation in parallel with laser operation. Light transmitted through the tissue was measured by a photodiode attached to an integrating sphere. RESULTS: Increasing the driving voltage of ultrasonic pulsation resulted in an increase in mean transmitted optical power of up to a factor of 1.742 ± 0.0526 times the control, wherein no ultrasound was applied, after which the optical power increase plateaued to an average amplification factor of 1.733 ± 0.549 times the control. CONCLUSIONS: The increase implies a reduction in light either back-scattered or absorbed within the tissue, which would allow for a greater proportion of incident energy to be delivered to the clinical target, thereby improving procedural efficacy and potentially reducing the severity of detrimental side-effects. Apparatus Lasers Surg. Med. 49:666-674, 2017. © 2017 Wiley Periodicals, Inc.

When Theater Comes to Engineering Design: Oh How Creative They Can Be.

The creative process is fun, complex, and sometimes frustrating, but it is critical to the future of our nation and progress in science, technology, engineering, mathematics (STEM), as well as other fields. Thus, we set out to see if implementing methods of active learning typical to the theater department could impact the creativity of senior capstone design students in the bioengineering (BE) department. Senior bioengineering capstone design students were allowed to self-select into groups. Prior to the beginning of coursework, all students completed a validated survey measuring engineering design self-efficacy. The control and experimental groups both received standard instruction, but in addition the experimental group received 1 h per week of creativity training developed by a theater professor. Following the semester, the students again completed the self-efficacy survey. The surveys were examined to identify differences in the initial and final self-efficacy in the experimental and control groups over the course of the semester. An analysis of variance was used to compare the experimental and control groups with p < 0.05 considered significant. Students in the experimental group reported more than a twofold (4.8 (C) versus 10.9 (E)) increase of confidence. Additionally, students in the experimental group were more motivated and less anxious when engaging in engineering design following the semester of creativity instruction. The results of this pilot study indicate that there is a significant potential to improve engineering students' creative self-efficacy through the implementation of a "curriculum of creativity" which is developed using theater methods.

Bone quality assessment techniques: geometric, compositional, and mechanical characterization from macroscale to nanoscale.

This review presents an overview of the characterization techniques available to experimentally evaluate bone quality, defined as the geometric and material factors that contribute to fracture resistance independently of areal bone mineral density (aBMD) assessed by dual energy x-ray absorptiometry. The methods available for characterization of the geometric, compositional, and mechanical properties of bone across multiple length scales are summarized, along with their outcomes and their advantages and disadvantages. Examples of how each technique is used are discussed, as well as practical concerns such as sample preparation and whether or not each testing method is destructive. Techniques that can be used in vivo and those that have been recently improved or developed are emphasized, including high resolution peripheral quantitative computed tomography to evaluate geometric properties and reference point indentation to evaluate material properties. Because no single method can completely characterize bone quality, we provide a framework for how multiple characterization methods can be used together to generate a more comprehensive analysis of bone quality to complement aBMD in fracture risk assessment.

PEG Functionalization of Whispering Gallery Mode Optical Microresonator Biosensors to Minimize Non-Specific Adsorption during Targeted, Label-Free Sensing.

Whispering Gallery Mode (WGM) optical microresonator biosensors are a powerful tool for targeted detection of analytes at extremely low concentrations. However, in complex environments, non-specific adsorption can significantly reduce their signal to noise ratio, limiting their accuracy. To overcome this, poly(ethylene glycol) (PEG) can be employed in conjunction with appropriate recognition elements to create a nonfouling surface capable of detecting targeted analytes. This paper investigates a general route for the addition of nonfouling elements to WGM optical biosensors to reduce non-specific adsorption, while also retaining high sensitivity. We use the avidin-biotin analyte-recognition element system, in conjunction with PEG nonfouling elements, as a proof-of-concept, and explore the extent of non-specific adsorption of lysozyme and fibrinogen at multiple concentrations, as well as the ability to detect avidin in a concentration-dependent fashion. Ellipsometry, contact angle measurement, fluorescence microscopy, and optical resonator characterization methods were used to study non-specific adsorption, the quality of the functionalized surface, and the biosensor's performance. Using a recognition element ratio to nonfouling element ratio of 1:1, we showed that non-specific adsorption could be significantly reduced over the controls, and that high sensitivity could be maintained. Due to the frequent use of biotin-avidin-biotin sandwich complexes in functionalizing sensor surfaces with biotin-labeled recognition elements, this chemistry could provide a common basis for creating a non-fouling surface capable of targeted detection. This should improve the ability of WGM optical biosensors to operate in complex environments, extending their application towards real-world detection.

Spatial patterns of sediment contamination and their influence on benthic infaunal communities in a highly tidal and industrial estuary in Atlantic Canada.

Sediment contamination can be elevated in ports, harbours, and estuaries with legacies of exploitation, negatively impacting infaunal invertebrate communities. Saint John Harbour (45.25° N, 66.05° W), New Brunswick, Canada, is an active harbour with strong tides and a long history of human activity. To examine spatial patterns of sediment contamination, samples were collected between 2011 and 2021 from subtidal sites near potential contaminant sources. Invertebrate data from the same samples were used to investigate potential effects on biological communities. Contaminant concentrations in the inner parts of the harbour were elevated compared to reference sites, but generally did not reach levels comparable to other highly contaminated harbours in the region. Effects on invertebrates were detectable, particularly at sites with higher contamination, although physical factors (depth, sediment grain size) were more important. Dynamic tidal conditions in the harbour may reduce the accumulation of contaminants in subtidal sediments and their impacts on infaunal communities.

Inactivation of Salmonella in nonintact beef during low-temperature sous vide cooking.

Sous vide cooking is a method of food preparation in which food is vacuum sealed and cooked in a water bath that is set to a precise temperature and circulated by a sous vide device. Due to ease of use and affordability, this cooking method has grown increasingly popular in food service kitchens and domestic settings. However, low-temperature, long holding time sous vide cooking recommendations from manufacturers and chefs in popular press raise food safety concerns - specifically those for the preparation of nonintact beef products. The objective of this experiment was to address these concerns by validating a 5 log reduction of Salmonella spp. in sous vide cooked, nonintact beef steaks. Beef semitendinosus sliced into 2.54 cm steaks were internally inoculated to 7 log with Salmonella Typhimurium, Enteritidis, and Heidelberg via a needle inoculation pin pad. Steaks were individually vacuum sealed, and sous vide cooked at 46.1, 51.6, and 54.4°C. The minimum time measured for a 5 log reduction at 51.6 and 54.4°C was 150 and 64.5 min, respectively (P < 0.01). Additionally, a 7.28 log final reduction was achieved at 51.6°C after 322.5 min (P < 0.01). However, 46.1°C was only able to achieve a final reduction of 2.01 log (P < 0.01) after a holding time of 420 min. The results of this experiment validate in sous vide cooked products the time and temperature combinations provided in the USDA-FSIS Appendix A guidance for a 5 log reduction of Salmonella spp. in meat products. Moreover, more research is needed with other relevant foodborne pathogens to determine if sous vide cooking below Appendix A recommendations could lead to unsafe products.

Temporal and Spatial Trends in Benthic Infauna and Potential Drivers, in a Highly Tidal Estuary in Atlantic Canada.

Infaunal invertebrate communities of coastal marine sediments are often impacted by human activities, particularly in harbours and estuaries. However, while many studies have attempted to identify the key factors affecting benthic infauna, few have done so for highly energetic tidal estuaries. Samples were collected over a decade (2011-2020) from a series of reference sites in Saint John Harbour (45.25° N, 66.05° W), a highly tidal estuary in the Bay of Fundy, Canada. These data were used to examine spatial and temporal trends in infaunal invertebrate communities and sediment properties and to determine the extent to which the biological patterns were driven by measured physical and chemical variables. There were substantial differences among sites in infaunal invertebrate abundance (median ranging from 688 to 13,700 individuals per square meter), infaunal species richness (median ranging from 8 to 22), and Shannon diversity (median ranging from 1.26 to 2.34); multivariate analysis also revealed variation in species composition among sites. Sediment contaminant concentrations also varied among sites, but differences tended to be smaller (e.g. median chromium concentrations ranging from 21.6 to 27.6 mg/kg). Sample contaminant concentrations were all below probable effect levels, and almost all below threshold effect levels (Canadian interim sediment quality guidelines), but relationships with biological data were still detectable. However, physical variables (depth, sediment characteristics) were better predictors of biological variables and community composition. These results confirm the importance of physical factors in shaping infaunal communities in soft-sediment habitats in tidally influenced coastal waters. Supplementary Information: The online version contains supplementary material available at 10.1007/s12237-023-01222-w.

Thermo-optic coefficient of polyisobutylene ultrathin films measured with integrated photonic devices.

The optical properties of polymeric materials, such as transmission loss and the thermo-optic coefficient, determine their utility in numerous applications, ranging from nanotechnology to the automotive and aerospace industries. However, because of the wide variation in the physical properties of polymers, many are unsuited for characterization using conventional techniques; consequently, their optical properties are unknown. One such polymer is polyisobutylene, which is viscous at room temperature and therefore is not compatible with conventional transmission loss and the thermo-optic coefficient characterization techniques because they rely on contact measurements. To overcome this, we have developed an integrated, microscale optical sensor that relies on an evanescent wave to study the material's optical behavior. Using this device, we successfully determined the refractive index, the transmission loss, and the thermo-optic coefficient of ultrathin films of polyisobutylene. The films are deposited on the sensor's silica surface using either spin coating or surface-initiated cationic polymerization, demonstrating the flexibility of this approach.

Tailoring the protein adsorption properties of whispering gallery mode optical biosensors.

Label-free biosensor technologies have the potential to revolutionize environmental monitoring, medical diagnostics, and food safety evaluation processes due to their unique combinations of high-sensitivity signal transducers and high-specificity recognition elements. This enables their ability to perform real-time detection of deleterious compounds at extremely low concentrations. However, to further improve the biosensors' performance in complex environments, such as wastewater, blood, and urine, it is necessary to minimize nonspecific binding, which in turn will increase their specificity, and decrease the rate of false positives. In the present work, we illustrate the potential of combining emerging high-sensitivity optical signal transducers, such as whispering gallery mode (WGM) microcavities, with covalently bound poly(ethylene glycol) (PEG) coatings of varying thickness, as an effective treatment for the prevention of nonspecific protein adsorption onto the biosensor surface. We monitor the sensitivity of the coated biosensor, and investigate the effect of PEG chain length on minimizing nonspecific adsorption via protein adsorption studies. Experimental results confirm not only that PEG-functionalization reduces nonspecific protein adsorption to the surface of the sensor by as much as a factor of 4 compared to an initialized control surface, but also that chain length significantly impacts the nonfouling character of the microcavity surface. Surprisingly, it is the short chain PEG surfaces that experience the best improvement in specificity, unlike many other systems where longer PEG chains are preferred. The combination of WGM microcavities with PEG coatings tuned specifically to the device will significantly improve the overall performance of biosensor platforms, and enable their wider application in complex, real-world monitoring scenarios.

Climate, currents and species traits contribute to early stages of marine species redistribution.

Anthropogenic climate change is causing a rapid redistribution of life on Earth, particularly in the ocean, with profound implications for humans. Yet warming-driven range shifts are known to be influenced by a variety of factors whose combined effects are still little understood. Here, we use scientist-verified out-of-range observations from a national citizen-science initiative to assess the combined effect of long-term warming, climate extremes (i.e., heatwaves and cold spells), ocean currents, and species traits on early stages of marine range extensions in two warming 'hotspot' regions of southern Australia. We find effects of warming to be contingent upon complex interactions with the strength of ocean currents and their mutual directional agreement, as well as species traits. Our study represents the most comprehensive account to date of factors driving early stages of marine species redistributions, providing important evidence for the assessment of the vulnerability of marine species distributions to climate change.

Radioembolization Dosimetry with Total-Body 90Y PET.

Transarterial radioembolization (TARE) is a locoregional radiopharmaceutical therapy based on the delivery of radioactive 90Y microspheres to liver tumors. The importance of personalized dosimetry to make TARE safer and more effective has been demonstrated in recent clinical studies, stressing the need for quantification of the dose-response relationship to ultimately optimize the administered activity before treatment and image it after treatment. 90Y dosimetric studies are challenging because of the lack of accurate and precise methods but are best realized with PET combined with Monte Carlo simulations and other image modalities to calculate a segmental dose distribution. The aim of this study was to assess the suitability of imaging 90Y PET patients with the total-body PET/CT uEXPLORER and to investigate possible improvements in TARE 90Y PET-based dosimetry. The uEXPLORER is the first commercially available ultra-high-resolution (171 cps/kBq) total-body digital PET/CT device with a 194-cm axial PET field of view that enables the whole body to be scanned at a single bed position. Methods: Two PET/CT scanners were evaluated in this study: the Biograph mCT and the total-body uEXPLORER. Images of a National Electrical Manufacturers Association (NEMA) image-quality phantom and 2 patients were reconstructed using our standard clinical oncology protocol. A late portal phase contrast-enhanced CT scan was used to contour the liver segments and create corresponding volumes of interest. To calculate the absorbed dose, Monte Carlo simulations were performed using Geant4 Application for Tomographic Emission (GATE). The absorbed dose and dose-volume histograms were calculated for all 6 spheres (diameters ranging from 10 to 37 mm) of the NEMA phantom, the liver segments, and the entire liver. Differences between the phantom doses and an analytic ground truth were quantified through the root mean squared error. Results: The uEXPLORER showed a higher signal-to-noise ratio at 10- and 13-mm diameters, consistent with its high spatial resolution and system sensitivity. The total liver-absorbed dose showed excellent agreement between the uEXPLORER and the mCT for both patients, with differences lower than 0.2%. Larger differences of up to 60% were observed when comparing the liver segment doses. All dose-volume histograms were in good agreement, with narrower tails for the uEXPLORER in all segments, indicating lower image noise. Conclusion: This patient study is compelling for the use of total-body 90Y PET for liver dosimetry. The uEXPLORER scanner showed a better signal-to-noise ratio than mCT, especially in lower-count regions of interest, which is expected to improve dose quantification and tumor dosimetry.