Will you treat brain mets with SRS in patients who cannot undergo MRI?

I agree with all of the previous comments. In addition, I'd like to add my own anecdotal experience. I saw a patient with widely metastatic melanoma who underwent head CT instead of an MRI brain due to the presence of pacemaker. There was a nodular enhancing focus read as suspicious for metastasis, and we discussed possibly treating it with SRS.

Subsequently, the patient was able to undergo MRI using special monitoring and protocols at our main academic campus, and after undergoing cardiology an...

On occasion, I have treated patients with SRS using CT (with contrast) alone. This was reserved for the rare patient who was unable to undergo MRI, had excellent functional status, wanted to avoid WBRT, and had more factors favoring oligometastatic disease (controlled primary, long intracranial disease-free interval, neurologically intact, etc.). Though it is more difficult to see the lesion(s), I believe the known toxicity of WBRT was greater than the potential toxicity of missing small lesions...

I would be reluctant to treat with SRS alone and would favor whole brain RT with or without an SRS boost, as a CT scan can underestimate the extent of disease and number of lesions. If treated with SRS alone, there may be an increased risk of neuro deficits from progression of small untreated brain mets.

Reasonable to do. I usually do a 2 mm margin (as opposed to my usual 1 mm) as the exact end of the lesion is less difficult to visualize compared to the CT head with contrast. There is an inherent risk of not catching smaller lesions with MRI, but to me, it is not enough reason to remove it as a treatment option.

Consider shorter timeframe surveillance scans given the potential for the present, but non-visible disease that was missed due to no MRI.

Assuming that radiation is the only modality felt appropriate at the time (for example, the patient is not felt to be a resection candidate by neurosurgery), yes.

One could either treat with whole brain now and potentially treat at progression later with SRS, or one could treat with SRS now and potentially treat with whole brain later if there was progression. Either way, I would consider using both modalities at some point in a patient's care, as I don't think it would be appropriate after givi...