Planetary Health and Radiology: Why We Should Care and What We Can Do.

Climate change adversely affects the well-being of humans and the entire planet. A planetary health framework recognizes that sustaining a healthy planet is essential to achieving individual, community, and global health. Radiology contributes to the climate crisis by generating greenhouse gas (GHG) emissions during the production and use of medical imaging equipment and supplies. To promote planetary health, strategies that mitigate and adapt to climate change in radiology are needed. Mitigation strategies to reduce GHG emissions include switching to renewable energy sources, refurbishing rather than replacing imaging scanners, and powering down unused scanners. Radiology departments must also build resiliency to the now unavoidable impacts of the climate crisis. Adaptation strategies include education, upgrading building infrastructure, and developing departmental sustainability dashboards to track progress in achieving sustainability goals. Shifting practices to catalyze these necessary changes in radiology requires a coordinated approach. This includes partnering with key stakeholders, providing effective communication, and prioritizing high-impact interventions. This article reviews the intersection of planetary health and radiology. Its goals are to emphasize why we should care about sustainability, showcase actions we can take to mitigate our impact, and prepare us to adapt to the effects of climate change. © RSNA, 2024 Supplemental material is available for this article. See also the article by Ibrahim et al in this issue. See also the article by Lenkinski and Rofsky in this issue.

Advancing learning equity through virtual radiology grand rounds.

PURPOSE: The COVID-19 pandemic rapidly accelerated the adoption of virtual learning in medical education, including departmental grand rounds lectures in radiology. This retrospective study sought to assess the impact of an open access virtual grand rounds program. We tested the hypothesis that virtual grand rounds would advance learning equity by increasing access to learners outside of our institution. METHODS: Twenty-two open access virtual grand rounds lectures were presented and recorded using an online videoconferencing platform. After the lecture, registrants received online access to the lecture recording for later on-demand viewing. The email address, geographical location, institutional affiliation, and medical specialty for all virtual registrants and attendees were retrospectively collected from a required online registration form. The primary outcome measure included an assessment of geographical diversity using descriptive statistics. RESULTS: Attendees of the virtual lectures were from 75 academic institutions and 27 non-academic institutions and located in 32 states, 88 cities, and 9 countries. Twenty-seven medical specialties were represented. CONCLUSION: The virtual grand rounds program in radiology contributes to free and open access educational content online for learners around the world. To address learning equity and promote international inclusion, we recommend that grand rounds organizers consider including a virtual option that allows free sharing of knowledge.

J-Difference editing (MEGA) of lactate in the human brain at 3T.

PURPOSE: The need to detect and quantify brain lactate accurately by MRS has stimulated the development of editing sequences based on J coupling effects. In J-difference editing of lactate, threonine can be co-edited and it contaminates lactate estimates due to the spectral proximity of the coupling partners of their methyl protons. We therefore implemented narrow-band editing 180° pulses (E180) in MEGA-PRESS acquisitions to resolve separately the 1.3-ppm resonances of lactate and threonine. METHODS: Two 45.3-ms rectangular E180 pulses, which had negligible effects 0.15-ppm away from the carrier frequency, were implemented in a MEGA-PRESS sequence with TE 139 ms. Three acquisitions were designed to selectively edit lactate and threonine, in which the E180 pulses were tuned to 4.1 ppm, 4.25 ppm, and a frequency far off resonance. Editing performance was validated with numerical analyses and acquisitions from phantoms. The narrow-band E180 MEGA and another MEGA-PRESS sequence with broad-band E180 pulses were evaluated in six healthy subjects. RESULTS: The 45.3-ms E180 MEGA offered a difference-edited lactate signal with lower intensity and reduced contamination from threonine compared to the broad-band E180 MEGA. The 45.3 ms E180 pulse had MEGA editing effects over a frequency range larger than seen in the singlet-resonance inversion profile. Lactate and threonine in healthy brain were both estimated to be 0.4 ± 0.1 mM, with reference to N-acetylaspartate at 12 mM. CONCLUSION: Narrow-band E180 MEGA editing minimizes threonine contamination of lactate spectra and may improve the ability to detect modest changes in lactate levels.

Climate Change and Radiology: Impetus for Change and a Toolkit for Action.

This special report discusses the importance of climate change for health care and radiology. The impact of climate change on human health and health equity, the contribution of health care and medical imaging to the climate crisis, and the impetus for change within radiology to create a more sustainable future are covered. The authors focus on actions and opportunities to address climate change in our role as radiologists. A toolkit highlights actions we can take toward a more sustainable future, linking each action with the expected impact and outcome. This toolkit includes a hierarchy of actions from first steps to advocating for system-level change. This includes actions we can take in our daily lives, in radiology departments and professional organizations, and in our relationships with vendors and industry partners. As radiologists, we are adept at managing rapid technological change, which makes us ideally suited to lead these initiatives. Alignment of incentives and synergies with health systems are highlighted given that many of the proposed strategies also result in cost savings.

Modeling the Environmental and Financial Impact of Multi-dose vs. Single-dose Iodinated Contrast Media Packaging and Delivery Systems.

RATIONALE AND OBJECTIVES: Iodinated contrast media (ICM) is used in computed tomography (CT) imaging to better visualize pathophysiology. ICM is commonly sold in "single-dose" bottles that require any unused volume to be discarded. Multi-dose bottles have been developed as an alternative packaging method. The objective of this study was to compare ICM waste, plastic waste, and the associated financial costs for both the single-dose and multi-dose ICM delivery systems. METHODS: Institutional data was used to estimate the average ICM administered per CT scan, average ICM wasted per CT scan, and the total ICM volume wasted annually. Waste estimates for the multi-dose bottles were generated by applying the average ICM administered per CT scan to the larger, multi-dose bottle volumes. Single-dose bottles, multi-dose bottles and injection syringes were weighed and used to calculate plastic waste generated by both packaging methods. Financial analysis was performed to compare the cost of supplies for single-dose and multi-dose ICM delivery systems. RESULTS: We found that 100 mL single-dose ICM bottles waste an average of 19.7 mL per CT scan, representing over 964 L of ICM wasted per year. The multi-dose ICM delivery system was projected to decrease pharmaceutical waste by at least 73% and reduce plastic waste by approximately 93%. We also estimate $494,000 in annual savings using the multi-dose ICM delivery method at our institution. CONCLUSION: Multi-dose ICM packaging can help conserve ICM, an important pharmaceutical that was only recently severely affected supply chain disruptions. The multi-dose delivery system can also reduce plastic waste and generate substantial financial savings to offset capital investment.

The 2022 AUR Academic Radiology and Industry Leaders Roundtable.

The Association of University Radiologists (AUR) convened its sixth annual Academic-Industry Roundtable in a hybrid fashion in March 2022, with academic radiology and radiology industry leaders gathered in person and via remote videoconference. The open discussion centered around on challenges facing radiology and specifically focused on the people in our field, including patients, radiologists, and radiology staff. Participants identified numerous opportunities for industry and radiology departments to collaborate to improve equitable access to healthcare, communication with patients, use of appropriate imaging, and the state of the radiology workforce.

Five Years Later: Impact of a Focused Women in Radiology Program.

PURPOSE: Women are underrepresented in radiology and experience barriers to professional growth that can affect job satisfaction and career advancement. The authors hypothesized that a structured, intentional Women in Radiology (WiR) program would increase women faculty members' perceptions of workplace gender equity, satisfaction with pace of professional advancement, interest in research and teaching, and perceptions of work-life balance and mentorship opportunities. METHODS: Components and structure of a sustainable WiR program are described in detail. Baseline and summative 5-year surveys of women faculty members in the department were distributed. The primary outcome measure was perception of equitable access to professional development opportunities for women. The authors also assessed the impact of the WiR program on creating a departmental culture shift to improve career advancement for women. Secondary outcomes included WiR's impact on women's satisfaction with pace of professional advancement, mentorship opportunities, work-life balance, and interest in research and teaching. RESULTS: Compared with 5 years prior, more women faculty members now believe that there is equitable access to career advancement opportunities and that the formal WiR program has contributed to a positive culture shift in the department. Significant gains in women faculty members' satisfaction with pace of their professional advancement were demonstrated. During the study period, more women developed interest in teaching and research, served as mentors, and perceived improvements in work-life balance compared with baseline. CONCLUSIONS: A structured, intentional WiR program can contribute to improved workplace gender equity, career satisfaction for women, and a positive departmental culture shift to support the needs of women in radiology.

Yttrium-90 Radioembolization in the VX2 Rabbit Model: Radiation Safety and Factors Influencing Delivery Efficiency.

The purpose of this study was to define the optimal infusion parameters and operator radiation exposure for yttrium-90 (90Y) radioembolization in the VX2 rabbit model of liver cancer. Forty-one rabbits with VX2 were treated with glass microspheres with vial sizes of 1, 3, and 5 GBq. The mean administered activity was 51.5 MBq (95% CI, 39.1-63.9). Delivery efficiency improved with 1 GBq versus with 3 GBq (residual 11.0% vs 46.4%, respectively; P = .0013) and improved with 1 GBq versus with 5 GBq (residual 11.0% vs 33.8%, respectively; P = .0060). The mean operator extremity exposure was 41.7 µSv/infusion. The optimal minimum infusion volume and rate was 49 mL and 21 mL/min, respectively. Fecal elimination occurred with microsphere uptake in the gallbladder at 1 and 2 weeks. 90Y radioembolization can be safely and efficiently performed in the VX2 rabbit model. Methodological considerations as a "how-to" for the setup of a preclinical 90Y laboratory are included to support future translational research.

Yttrium-90 Radioembolization and Tumor Hypoxia: Gas-challenge BOLD Imaging in the VX2 Rabbit Model of Hepatocellular Carcinoma.

RATIONALE AND OBJECTIVES: To use a rapid gas-challenge blood oxygen-level dependent magnetic resonance imaging exam to evaluate changes in tumor hypoxia after 90Y radioembolization (Y90) in the VX2 rabbit model. MATERIALS AND METHODS: White New Zealand rabbits (n = 11) provided a Y90 group (n = 6 rabbits) and untreated control group (n = 5 rabbits). R2* maps were generated with gas-challenges (O2/room air) at baseline, 1 week, and 2 weeks post-Y90. Laboratory toxicity was evaluated at baseline, 24 hours, 72 hours, 1 hours, and 2 weeks. Histology was used to evaluate tumor necrosis on hematoxylin and eosin and immunofluorescence imaging was used to assess microvessel density (CD31) and proliferative index (Ki67). RESULTS: At baseline, median tumor volumes and time to imaging were similar between groups (p = 1.000 and p = 0.4512, respectively). The median administered dose was 50.4 Gy (95% confidence interval:44.8-55.9). At week 2, mean tumor volumes were 5769.8 versus 643.7 mm3 for control versus Y90 rabbits, respectively (p = 0.0246). At two weeks, ΔR2* increased for control tumors to 12.37 ± 12.36sec-1 and decreased to 4.48 ± 9.00sec-1 after Y90. The Pearson correlation coefficient for ΔR2* at baseline and percent increase in tumor size by two weeks was 0.798 for the Y90 group (p = 0.002). There was no difference in mean microvessel density for control versus Y90 treated tumors (p = 0.6682). The mean proliferative index was reduced in Y90 treated tumors at 30.5% versus 47.5% for controls (p = 0.0071). CONCLUSION: The baseline ΔR2* of tumors prior to Y90 may be a predictive imaging biomarker of tumor response and treatment of these tumors with Y90 may influence tumor oxygenation over time.

Correlation and Agreement of Yttrium-90 Positron Emission Tomography/Computed Tomography with Ex Vivo Radioembolization Microsphere Deposition in the Rabbit VX2 Liver Tumor Model.

PURPOSE: To demonstrate a stronger correlation and agreement of yttrium-90 (90Y) positron emission tomography (PET)/computed tomography (CT) measurements with explant liver tumor dosing compared with the standard model (SM) for radioembolization. MATERIALS AND METHODS: Hepatic VX2 tumors were implanted into New Zealand white rabbits, with growth confirmed by 7 T magnetic resonance imaging. Seventeen VX2 rabbits provided 33 analyzed tumors. Treatment volumes were calculated from manually drawn volumes of interest (VOI) with three-dimensional surface renderings. Radioembolization was performed with glass 90Y microspheres. PET/CT imaging was completed with scatter and attenuation correction. Three-dimensional ellipsoid VOI were drawn to encompass tumors on fused images. Tumors and livers were then explanted for inductively coupled plasma (ICP)-optical emission spectroscopy (OES) analysis of microsphere content. 90Y PET/CT and SM measurements were compared with reference standard ICP-OES measurements of tumor dosing with Pearson correlation and Bland-Altman analyses for agreement testing with and without adjustment for tumor necrosis. RESULTS: The median infused activity was 33.3 MBq (range, 5.9-152.9). Tumor dose was significantly correlated with 90Y PET/CT measurements (r = 0.903, P < .001) and SM estimates (r = 0.607, P < .001). Bland-Altman analyses showed that the SM tended to underestimate the tumor dosing by a mean of -8.5 Gy (CI, -26.3-9.3), and the degree of underestimation increased to a mean of -18.3 Gy (CI, -38.5-1.9) after the adjustment for tumor necrosis. CONCLUSIONS: 90Y PET/CT estimates were strongly correlated and had better agreement with reference measurements of tumor dosing than SM estimates.

Yttrium-90 Portal Vein Radioembolization in Sprague-Dawley Rats: Dose-Dependent Imaging and Pathological Changes in Normal Liver.

PURPOSE: Portal vein embolization (PVE) is an established neoadjuvant method to induce future liver remnant hypertrophy prior to surgical resection of hepatic tumors. The purpose of our study was to examine the feasibility of PVE with glass 90Y microspheres (Y90 PVE) in Sprague-Dawley rats. We tested the hypothesis that increased doses of Y90 PVE would increase target lobe fibrosis and atrophy. METHODS: Twenty-two rats were assigned to four groups for Y90 PVE to the right median lobe: very high- (273.8 MBq; n = 2), high- (99.9 MBq; n = 10), medium- (48.1 MBq; n = 5), and low-dose (14.8 MBq; n = 5). An untreated control group included seven rats. 90Y PET/CT of 90Y distributions confirmed lobar targeting. MRI volumes were measured at baseline, 2-, 4-, 8- and 12-weeks. Explanted hepatic lobes were weighed, sectioned, and stained for H&E and immunohistochemistry. Digitized slides allowed quantitative measurements of fibrosis (20 foci/slide). RESULTS: Ex vivo measurements confirmed 91-97% activity was localized to the target lobe (n = 4). The percent growth of the target lobe relative to baseline was - 5.0% (95% CI - 17.0-6.9%) for high-, medium dose rats compared to + 18.6% (95% CI + 7.6-29.7%) in the low-dose group at 12-weeks (p = 0.0043). Radiation fibrosis increased in a dose-dependent fashion. Fibrotic area/microsphere was 22,893.5, 14,946.2 ± 2253.3, 15,304.5 ± 4716.6, and 5268.8 ± 2297.2 µm2 for very high- (n = 1), high- (n = 4), medium- (n = 3), and low-dose groups (n = 5), respectively. CONCLUSION: Y90 PVE was feasible in the rat model, resulted in target lobe atrophy, and dose-dependent increases in hepatic fibrosis at 12 weeks. The onset of imaging-based volumetric changes was 8-12 weeks.

Feasibility of Combination Intra-arterial Yttrium-90 and Irinotecan Microspheres in the VX2 Rabbit Model.

PURPOSE: To evaluate the combination of 90Y radioembolization (Y90) and drug-eluting bead irinotecan (DEBIRI) microspheres in the VX2 rabbit model. MATERIALS AND METHODS: An initial dose finding study was performed in 6 White New Zealand rabbits to identify a therapeutic but subcurative dose of Y90. In total, 29 rabbits were used in four groups: Y90 treatment (n = 8), DEBIRI treatment (n = 6), Y90 + DEBIRI treatment (n = 7), and an untreated control group (n = 8). Hepatic toxicity was evaluated at baseline, 24 h, 72 h, 1 week, and 2 weeks. MRI tumor volume (TV) and enhancing tumor volume were assessed baseline and 2 weeks. Tumor area and necrosis were evaluated on H&E for pathology. RESULTS: Infused activities of 84.0-94.4 MBq (corresponding to 55.1-72.7 Gy) were selected based on the initial dose finding study. Infusion of DEBIRI after Y90 was technically feasible in all cases (7/7). Overall, 21/29 animals survived to 2 weeks, and the remaining animals had extrahepatic disease on necropsy. Liver transaminases were elevated with Y90, DEBIRI, and Y90 + DEBIRI compared to control at 24 h, 72 h, and 1 week post-treatment and returned to baseline by 2 weeks. By TV, Y90 + DEBIRI was the only treatment to show statistically significant reduction at 2 weeks compared to the control group (p = 0.012). The change in tumor volume (week 2-baseline) for both Y90 + DEBIRI versus control (p = 0.002) and Y90 versus control (p = 0.014) was significantly decreased. There were no statistically significant differences among groups on pathology. CONCLUSION: Intra-arterial Y90 + DEBIRI was safe and demonstrated enhanced antitumor activity in rabbit VX2 tumors. This combined approach warrants further investigation.