How long after resection for brain metastasis do you wait to request a radiation planning MRI?

This is a good question, and I agree with the sentiments above. I think there are two competing issues here--1) evolution of the cavity and 2) regrowth of microscopic disease.

While intuitively, one might think that waiting longer might allow the brain to normalize and the cavity to shrink, our data ...

Assuming this is a patient with one or limited brain metastases and the resection is complete (gross total resection), I would consider obtaining an MRI within 30 days. For large resection cavities, there's data showing cavity reduction >= 1 month (Shah et al., PMID 27222693) which may help reduce S...

Unfortunately, there is not a hard & fast answer to this question. There are some general parameters but each patient might be different. The key is to obtain the MRI before you have obliteration of the cavity. My general rule of thumb is around 10-14 days post surgery. In my own experience, it is t...

I have always approached this question considering 3 factors to determine the timing of post op cavity planning MRI, CT sim, and starting treatment to brain met resection cavities. We deliver fractionated SRS for post op cavities (9 Gy x 3 or 6 Gy x 5). The timing of the planning MRI obviously impac...