Erratum: Yttrium-90 Radioembolization Dosimetry: What Trainees Need to Know Yttrium-90 radioembolization (Y90-RE), also known as transarterial radioembolization (TARE) or selective internal radiation therapy (SIRT), is a form of brachytherapy that has become an established liver-directed therapy for primary and secondary hepatic malignancies.[1] [2] [3] [4] [5] [6] [7] While a degree of embolization and ischemia may occur, the dominant mechanism of action for Y90-RE is radiation-induced necrosis from targeted transarterial administration of millions of Y90-labeled microspheres. The Y90 within these microspheres exert their effects primarily by undergoing β-decay to stable zirconium-90, which is not known to have any clinical effects.[8] [9] [10] The β-decay of Y90 results in the release of high-energy β-particles (i.e., electrons or β−) with an average energy of 0.9267 MeV (maximum of 2.28 MeV) and a half-life of 64.04 hours (2.67 days), which translates to 94% of the Y90 radiation being delivered within 11 days. These β-particles penetrate nearby tissues an average of 2.5 mm (maximum of 11 mm), resulting in the sought-after effect of radiation damage to nearby structures.[11] Additional types of radiation also occur as a result of Y90 decay. Although these are summarized in [Fig. 1], an in-depth discussion of them is beyond the scope of this article. Currently, there are two commercially available and Food and Drug Administration (FDA)-approved radioembolization microspheres in the United States: resin microspheres (SIR-Spheres; Sirtex Medical Inc, Woburn, MA), whose original formulations were developed in the mid-20th century, and glass microspheres (TheraSphere; Boston Scientific, Marlborough, MA), which were developed in the early 1980s.[9] Properties of these biocompatible and nonbiodegradable microspheres, at the time of calibration, are outlined in [Table 1].[9] [12] [13] Resin microspheres are FDA approved only for the treatment of unresectable metastatic liver tumors (MLTs) from primary colorectal cancer with adjuvant intrahepatic artery chemotherapy (IHAC) of FUDR (Floxuridine).[14] Glass microspheres are FDA approved, under a humanitarian drug exemption, only for the sole or neoadjuvant treatment of unresectable hepatocellular carcinoma (HCC).[15] Nevertheless, both types of microspheres are frequently used off-label for the treatment of various primary or secondary hepatic malignancies.[16] [17] As a result of the mounting evidence for a clear dose–effect relationship,[10] the goal of Y90-RE has evolved to reflect a classical principle of oncology—which is to deliver the maximum tolerated dose. Achieving this goal requires understanding of the multiple steps in the pre-, peri-, and posttherapy phases of Y90-RE. Several articles have sought to comprehensively explain the rationale and technical challenges found in each of these steps.[18] [19] However, a paucity of literature comprehensively describing the technical strengths and challenges of the commonly used Y90-RE dosimetry models remains. As an integral part of the team and an authorized user of Y90-RE devices, the interventional radiologist must have a fundamental understanding of the involved dosimetry. Therefore, the aim of this article is to provide a fundamental background of the rationale, limitations, and strengths involved in Y90-RE dosimetry planning, and the strategies employed in clinical practice when treating patients with Y90-RE. Publication Date: 11 December 2020 (online) © 2020. Thieme. All rights reserved. Thieme Medical Publishers, Inc. 333 Seventh Avenue, 18th Floor, New York, NY 10001, USA

To evaluate the safety and efficacy of combining yttrium-90 radioembolization (Y90-RE) with immune checkpoint inhibitor therapy, consecutive advanced unresectable hepatocellular carcinoma (HCC) patients treated between 2016 and 2022 with atezolizumab/bevacizumab or nivolumab within three-months pre- and post-Y90-RE were retrospectively evaluated. Tumor response and treatment-related clinical/laboratory adverse events (AE) were assessed at 1 and 6 months, as well as differences in clinical and laboratory variables and median overall survival (OS) from initial treatment (whether it was Y90-RE or systemic therapy) between the two cohorts. A total of 19 patients (10 atezolizumab/bevacizumab; 9 nivolumab), comprising 84% males with median age 69 years, met the inclusion criteria. Compared to the atezolizumab/bevacizumab group, there were less males (100% vs. 67%; p = 0.02) and more ECOG ≥ 2 patients in the nivolumab group (0% vs. 33%; p = 0.02). Baseline characteristics or incidence of 6-month post-treatment any-grade AE (60% vs. 56%; p = 0.7), grade ≥ 3 AE (0% vs. 11%; p = 0.3), objective response (58% total, 60% vs. 56%; p = 0.7), and complete response (16% total; 10% vs. 22%; p = 0.8) were similar between the atezolizumab/bevacizumab and the nivolumab cohorts. Median OS was 12.9 months for the whole cohort, 16.4 months for nivolumab, and 10.7 months for atezolizumab/bevacizumab. Among patients with advanced unresectable HCC, the utilization of Y90-RE concurrently or within 90 days of nivolumab or atezolizumab/bevacizumab immunotherapy, appears to be well-tolerated and with a low incidence of severe AE.

<!-- *** Custom HTML *** --> Computer vision syndrome (CVS) is an umbrella term for a pattern of symptoms associated with prolonged digital screen exposure, such as eyestrain, headaches, blurred vision, and dry eyes. Commercially available blue light filtering lenses (BLFL) are advertised as improving CVS. Our pilot study evaluates the effectiveness of BLFL on reducing CVS symptoms and fatigue in a cohort of radiologists. A prospective crossover study was conducted with ten radiology residents randomized into two cohorts: one wearing BLFL first then a sham pair (non-BLFL), and the other wearing a sham pair first then BLFL, over two weeks during normal clinical work. Participants filled out a questionnaire using the validated computer vision syndrome questionnaire (CVS-Q) and the Swedish Occupational Fatigue Inventory (SOFI). The majority of symptoms [11/16 (68.8%) and 13/16 (81.3%) symptoms on the CVS-Q and SOFI, respectively] were reduced (i.e., symptoms less severe) with the BLFL compared to the sham glasses. Females rated symptoms of sleepiness and physical discomfort in the SOFI, and overall CVS-Q, as more severe. Postgraduate year (PGY)-2 residents rated all symptoms as more severe than PGY-3/4s. BLFL may ameliorate CVS symptoms. Future studies with larger sample sizes and participants of different ages are required to verify the potential of BLFL.

As a form of brachytherapy, yttrium-90 radioembolization (Y90-RE), also known as selective internal radiation therapy (SIRT) or trans-arterial radioembolization (TARE), exerts its locoregional tumoricidal effects by its near-pure emission of beta-particles from the radioactive decay of yttrium-90 ([Table 1]). Since its early therapeutic use for the palliative treatment of patients with advanced unresectable hepatocellular carcinoma (HCC), there has been recognition that the tumor response to Y90-RE will be dependent on the relationship between the delivered activity and dose administered. This appreciation for the importance of dosimetry also stemmed from the recognition that liver toxicity can occur due to delivering “too much dose”—specifically, the recognition of radiation-induced liver disease (RILD).[1] Throughout the years, the need for accurate dosimetric analysis prior to dose delivery has been demonstrated to improve outcomes.[2] With this endeavor in mind, there have been many rapid developments within the Y90 dosimetry space. This amount of rapidly developing information has left the potential new Y90-RE user with a great deal of information to digest as they learn to “how much dose to give” and how to efficiently do so. As such, the aim of this article is to provide a central and easy-to-digest source of information for Y90-RE dosimetry. Tips and considerations, with the author's opinion whenever data are lacking, will be shared as it pertains to Y90-RE of HCC—which currently has the most published data. A.V.: Conceptualization, methodology, formal analysis, resources, data curation, writing—original draft, writing—review and editing, and visualization. J.L.D.P.: Writing—original draft, writing—review and editing, and visualization. R.T.G.: Writing—review and editing. N.K.: Conceptualization, methodology, resources, writing—review and editing, and supervision. Article published online: 14 March 2024 © 2024. Thieme. All rights reserved. Thieme Medical Publishers, Inc. 333 Seventh Avenue, 18th Floor, New York, NY 10001, USA