Proton therapy offers incremental, if any advantage, over standard IMRT for non-pediatric cases. In the case of the prostate, recent evidence shows no benefit at all. It suffers from near hyperbolic marketing from debt-ridden therapy centers pushing dubious claims that are now being exposed by high quality phase III comparison trials.
HIFU for prostate also is a ripe area for grifters as it is advertised and marketed towards low risk cases that would probably benefit from active surveillance.
Non-Cartesian sampling of k-space is routinely used today in clinical practice and the reconstruction time or resources isn't a limiting factor. It is the reduced SNR among other effects that is limiting in these approaches.
If one MRI scanner can be more efficient, there is enough competition in the market for it to be wildly successful. The major vendors have enough technical parity for efficiency to be a key difference maker. Hospitals and health systems are the customer and they need throughput.
I'm not sure what the point this article is trying to make. The image isn't the data for a lot of imaging modalities. The process of image reconstruction is translation from raw signal to image in any modality.
Gaining access to raw data is difficult. For example, if I want access to raw projection data on CT, it requires specific research keys and agreements with the vendor. A typical end user, like a hospital, cannot get to this raw data as part of a standard purchase.
Shielding is not a crude term, it is indeed used as technical language in the world of radiation safety. You are also using the term attenuation incorrectly, as sibling comment points out.