Dr. Amy Nett: Okay, so I’m going to back up a little bit here. So when we think about it, I’m wondering why in the world they’re getting so many imaging studies. I mean that’s sort of the question here because yes, I absolutely think about how many imaging studies someone’s had and if someone has cancer, it’s justified because you need to follow up. Like sometimes you’re actually using that imaging to make changes and determine treatment course. So I think it might be helpful to have a little more context. Why is she getting all of these studies? The other thing that you have to consider, so you said several CT scans and several radiographs. You mentioned one MRI, but remember MRI is magnetic resonance imaging. So that doesn’t have any radiation. So MRIs are not associated with any radiation, they only use strong magnetic fields to affect hydrogen precession. Risks associated with MRI, incredibly, incredibly low especially if it’s a noncontrast MRI.
So MRI ultrasound, don’t worry about it. CT scans and radiographs. The problem with understanding the approximate effective radiation dose from each of these tests is that you need to take into account how big the person is and, somewhat unfortunately, how good the radiology techs are at lowering radiation dose. Most of the CT scanners and radiograph machines, as long as the settings are on appropriately for automatic dose lowering, they are going to adjust. So a smaller person with less fat is going to have much lower of the radiation dose than a thin person who really doesn’t have a lot of body fat. Because you’re thinking about x-ray penetration here. So you kind of have to know the person’s size.
The other thing is what body parts are being imaged. If you’re doing like a chest, abdomen, pelvis CT versus lower extremity CT, and I’m guessing anyone who’s getting multiple CT scans, I’m guessing it’s probably abdomen and pelvis because it’s probably some chronic pain something like that. So have we refused to do studies on patients because they’ve had so many exams? I personally have. As a radiologist I would, particularly when I was a pediatric radiologist, it was more because I would see clinicians ordering studies that I thought were absolutely unnecessary. And I would look through their file and see how many studies have been done let’s say in the past year, and I would say no way. Like I’m not going to do another CT scan, I’m not going to do another radiograph. We can consider MRI, we can consider ultrasound, but yeah I think it’s very reasonable for people to say no we’re not going to do more CTs, radiographs.
Again, we can’t know exactly. Unless she’s wearing a radiation dosimeter to measure her dose, then we’re not going to know how much radiation she had specifically. Radiographs are relatively low in radiation. That said, they’re also pretty uninformative, especially if you’re just looking at abdomen or pelvis. You don’t get a lot of information. So again, the question really needs to be what are you looking what you looking for with the imaging studies because I would almost, you can almost always answer an imaging question with an MRI or an ultrasound. It’s rare that you actually need a CT.
So it’s off-topic so I’ll sort of end my answer there because obviously I could talk about it for a lot longer. So let me know if there’s a more specific question about that. But the answer is basically yes, she should be refused imaging if it’s unnecessary because of the amount of prior radiation. You’re not going to get a lot more information from a fifth or sixth CT scan done in one year, unless you’re specifically tracking something like nodal metastases, cancer growth, or something like that. So hopefully that answers your question. But again, if there are more specifics let me know.