HR 2541: How May Its Implementation Impact Radiation Oncology Practice?

Thomas Hope, MD

University of California, San Francisco

HR 2541, the Nuclear Medicine Clarification Act of 2025, purports to increase transparency in reporting radiopharmaceutical leakage.1 However, some clinicians argue that its impact is opaque and may ultimately not address any clinically relevant outcomes in practice.

One such proponent, Thomas Hope, MD, vice chair of clinical operations and strategy and professor in the Department of Radiology at the University of California, San Francisco (UCSF), said he is unsure what clinical issue the bill is seeking to remedy.

In an interview with CancerNetwork®, Hope discussed the background of the legislation, as well as the benefit it may seek to deliver for radiopharmaceutical administration. Although Hope acknowledged the incidence of dose infiltrations, whereby nuclear material exits the vein and leaks into local tissue, in his experience, he has not observed a single adverse effect (AE) associated with such an event.

Addressing the aim of the bill, Hope posited that infiltrations may happen with any intravenously delivered medicine and that reporting requirements may help to better track their occurrence. However, he questioned whether effectively tracking the incidence of these events would fix any clinical issues, citing that at UCSF, infrequent infiltrations are reported with imaging agents, and radiopharmaceuticals are given at a volume too small to harm tissue.

Hope concluded by distinguishing between imaging agents and therapeutic agents, with a significantly greater potential for toxicity with therapeutic agents. For the latter, he highlighted ongoing research that is exploring the relationship between radioactive dose administration and extratumoral toxicities. Finally, he touched upon an ongoing initiative that the Nuclear Regulatory Commission (NRC) is undertaking that he believes is already addressing concerns the bill is aiming to resolve.2

CancerNetwork: Can you outline the issue HR 2541 is seeking to address?

Hope: [HR 2541] is trying to increase the reporting requirements for, in essence, nuclear medicine when they administer radioactive compounds through an IV into an arm. The idea here is that when you inject anything through an IV, sometimes it goes directly into the vein throughout your body, as it’s intended to. Other times, it can stay in the arm, what we call infiltration. It leaves the vein and then goes out into the tissue in the arm. That can happen with any type of IV that is being administered. [It can happen] with chemotherapies, it can happen with intravenous contrast for CT or MRI, and it can also happen in the setting of radiopharmaceutical administrations. Infiltration is a common issue. This bill is trying to increase the reporting requirements so that, presumably, we can track this better.

A better question is, what’s the clinical problem it’s trying to fix? Do we have an issue with infiltrations out there? Is there a high incidence of this with [AEs or] patients having injuries to their arm because of infiltrations in radiopharmaceuticals? I would probably argue no. At UCSF, we do 10,000 PET-CTs a year [and] nearly 1000 therapies with therapeutic doses a year, where we use IVs [and] administer radiopharmaceuticals––and I have never heard of a single case of an AE in the 10 to 15 years I have been working at [UCSF]. The goal of the bill is to increase reporting requirements, but I am not sure what it’s trying to address. Is there a clinical problem that we need to fix because of these increased reporting requirements?

What impact would the passage of this bill have on clinical practice?

The actual details of how [the bill] impacts clinical practice are not entirely clear. What I mean by that is it requires dosimetry evaluation of patients; to measure the amount of radioactivity left in the arm after a treatment. That, in a therapeutic setting, could require multiple imaging time points––a patient [might have] to come back in to measure the activity in the arm over multiple days, particularly for radiopharmaceuticals that have longer half-lives. That would obviously have a huge impact in terms of patient workflow, having patients come back and forth between the center to have these measurements being performed, and to measure the amount of activity that’s left in the arm. You would have to do that across all patients because you would not know which patients have any infiltration in their arms.

Maybe I did not address this earlier, but when something infiltrates into the arm, it gets reabsorbed. It does not stay in the arm permanently. Theoretically, when you have infiltrations, there is risk to damage the tissue from the physical mass of the infiltrate. Then, there is also potentially a risk of some radiation injury. We have radioactivity, and it sits in the arm. Could you injure the arm from radiation? With the mass, this happens all the time with CT scans [and] MRIs; we have infiltration. When I say all the time, I mean 1 in 1000 [or] 1 in 10,000 types of rates. When it does happen, we have physicians on site. I am in a building today where we [perform] probably 100 CT scans a day; maybe once a month, we have an infiltration [for which] we need to go down, do a physical exam, check on it, et cetera. With radiopharmaceuticals, the volumes are much [lower], so when you’re doing a CT scan, you are administering 100 to 150 mL––a soda can volume. When you are doing it with a radiopharmaceutical, typically, we are administering between 10 and 30 mLs. It is not enough to physically injure the tissue. It is a theoretical risk of some injury from the radioactivity, which, to date, has never been reported. That type of injury from the radiation does not happen. Or if it does happen, it is well less than 1 in 10,000, the rate at which that injury would occur.

If HR 2541 aims to modify regulations related to electronic health records, how might these changes affect the current workflows for documentation, data entry, and information retrieval within clinical practice?

At the moment, it is not entirely clear how one would address the requirements of this bill. How does it impact documentation? I think we will have to figure that out. What do we need to be able to meet the requirements of this bill? You must report the radioactivity that’s left behind in the arm, in all patients, and you must measure that amount [and] put it into the report. Sometimes, those measurements will take multiple days to do. You would be delaying the time when this report would be generated because you would have to either amend it or put the documentation in there. It is potentially an issue in terms of the workflow in the clinic and in terms of how we do this.

The other thing to keep in mind is the biggest issue in radiopharmaceutical therapies is access. Do we have enough sites that can do these types of therapies out there and getting more centers to be able to do these treatments and imaging studies? This would be another impediment to increasing the availability of sites and locations for patients to have access to these therapies and these imaging agents.

How can one effectively monitor the progress and potential impact of HR 2541 and advocate for amendments that best support patient care and clinical practice?

I would break that question up into 2 parts. One is, we will not be able to monitor it. What I mean by that is there is no clinical AE or something we are trying to fix. If you were to implement a bill to try to fix something, you measure how often that thing occurs, and then you minimize it. [Let’s say] a lot of people have injuries to their arm because of radiopharmaceuticals. We measure the rate of that, and we know that it’s going down because we are measuring the dose that goes in the arm. We would be measuring an improvement in some patient-centric care. We are not going to be able to measure that because there is no “that”; “that” does not actually exist.

On the other hand, it will allow us to measure how many people are reporting doses. We could measure the implementation and rate of uptake. We could measure that. That’s more of [measuring] our measurement. But it is not clinically relevant or helping patients out, which is [ultimately] the goal of most of what we do [in our] daily practice.

What other developments regarding the safe administration of radiation therapy do you believe have the potential to impact the treatment paradigm?

I am going to focus, here, on therapies. There are 2 broad categories in nuclear medicine: imaging agents and therapeutic agents. Acute toxicity with imaging agents is [quite] rare, but therapies, on the other hand, do have toxicities. We administer relatively high doses of radioactivity, they go into the body, and they hopefully go to treat the tumor. But they also go to the liver, the kidneys, the bone marrow, et cetera. There’s a ton of work going on right now to understand the relationship between that radioactivity—the energy that’s deposited—and the subsequent development of toxicity.

Many research groups are trying to understand that relationship so that we can better prepare and understand which patients may or may not have these subsequent, what I would call, systemic toxicities. That is not very common, but that happens in [approximately] 10% of patients. We need to understand what’s going on with that, and that is much more imperative for us to understand moving forward.

The other thing, here, that’s important to keep in mind is that [H.R. 2541] is being pushed through for specific reasons, but it disregards a natural process that’s going on. The NRC, the national regulatory oversight committee that manages radioactivity and safety in the US, is reviewing infiltration processes, reporting guidelines, et cetera. They are going to come up with a set of guidelines [in 2026] to consider various parties, influences, and ideas to see the best way to do something about this. [H.R. 2541] is overstepping that and, in essence, trying to legislate and force people to do something for what I would consider biased reasons, whereas the normal process is ongoing right now. I would recommend considering letting that move forward in its normal path to see what those recommendations come out to be.

References

1. HR2541 - Nuclear Medicine Clarification Act of 2025, 119th Cong (2025). Updated April 1, 2025. Accessed November 24, 2025. https://tinyurl.com/33n97vjr
2. Rulemaking: reporting nuclear medicine injection extravasations as medical events. US Nuclear Regulatory Commission. Accessed November 24, 2025. https://tinyurl.com/mryrxacd