A simple and efficient method of covalently coupling the strong chelator diethylenetriaminepentaacetic acid to proteins was developed for radiolabeling immunoglobulin G antibodies. After being coupled and labeled with indium-111, a monoclonal antibody to carcinoembryonic antigen retained its ability to bind to its antigen in vitro and in vivo. In nude mice with a human colorectal xenograft, 41 percent of the injected radioactivity became localized in each gram of xenograft at 24 hours compared with 9 percent for control antibody and 19 percent for radioiodinated antibody to carcinoembryonic antigen.

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Introduction The widespread coronavirus disease 2019 (COVID-19) has resulted in significant changes in care delivery among radiation oncology practices and demanded the rapid incorporation of telehealth. However, the impact of a large-scale transition to telehealth in radiation oncology on patient access to care and the viability of care delivery are largely unknown. In this manuscript, we review our implementation and report data on patient access to care and billing implications. As telehealth is likely to continue after COVID-19, we propose a radiation oncology-specific algorithm for telehealth. Material and Methods In March 2020, our department began to use telehealth for all new consults, post-treatment encounters, and follow-up appointments. Billable encounters from January to April 2020 were reviewed and categorized into one of the following visit types: in-person, telephonic, or two-way audio-video. Logistic regression models tested whether visit type differed by patient age, income, or provider. Results There was a 35% decrease in billable activity from January to April. In-person visits decreased from 100% to 21%. Sixty percent of telehealth appointments in April were performed with two-way audio-video, and 40% by telephonic only. In-person consultation visits were associated with higher billing codes compared to two-way audio-video telehealth visits (p<0.01). No difference was seen for follow-up visits. Univariate and multivariable analysis identified that older patient age was associated with reduced likelihood of two-way audio-video encounters (p<0.01). The physician conducting the telehealth appointment was also associated with the type of visit performed (p<0.01). Patient income was not associated with the type of telehealth visit. Conclusions Since the onset of COVID-19 pandemic, we were able to move the majority of patient visits to telehealth but observed inconsistent utilization of the audio-video telehealth platform. We present guidelines and quality metrics for incorporating telehealth in radiation oncology practice, based on type of encounter and disease subsite.

Iodinated analogues 2, 7, and 8 were prepared from propranolol, practolol, and acebutolol in 30--50% yields. Radioisotopic exchange between carrier-free Na125I and the molten iodinated beta-adrenergic antagonist yielded the corresponding 125I-labeled product. The biodistribution in rats, determined at 15 and 60 min postinjection, indicated that the radioiodinated analogues of the cardioselective drugs practolol and acebutolol localized to a greater degree in the liver and heart than the analogue of propranolol. Conversely, [125I]iodopropranolol (2) was concentrated to a greater extent in the lungs than [125I]iodopractolol (7) or [125I]iodoacebutolol (8). Therefore, 123I- or 131I-labeled cardioselective beta-adrenergic antagonists, such as 7 or 8, may prove useful as radiodiagnostic agents for the external imaging of the myocardium.