If you build it, who will use it?

Nanox.Arc device, as it stands today, is fake.  But what if Nanox used its $200+ million cash to actually design and build its proposed device?  Will it be useful?

Nanox claims that its proposed device uses a modality ("imaging technique") - tomosynthesis - that is supposedly "widely used for early detection" of something.

Subject to receiving regulatory clearance, the first version of the Nanox.ARC that we expect to introduce to the market will be a 3D tomosynthesis imaging system. Tomosynthesis is an imaging technique widely used for early detection, that is designed to produce a high-resolution, 3D X-ray image reconstruction of the scanned human body part for review by a professional diagnostics expert (annual report, page 56)

Tomosynthesis (previously called x-ray tomography, focal plane tomography, etc) has been available since 1930s - it should not to be confused with CT or computed tomography, which can visualize axial slices and individual voxels.  

tomosynthesis vs. plain, per Nanox demo at RSNA 2020 

Even though various medical device manufacturers have pushed it over the years, its use has never been wide.  It never added much to simple x-rays taken from different views... 

In 1993, the American College of Radiology (ACR) started work on developing guidelines for radiology to eliminate inappropriate utilization of radiologic services.  Today,

ACR Appropriateness Criteria are evidence-based guidelines to assist referring physicians and other providers in making the most appropriate imaging or treatment decision for a specific clinical condition. Employing these guidelines helps providers enhance quality of care and contribute to the most efficacious use of radiology.

Of the nearly 1,000 radiological procedures covered by the criteria, only three are based on tomosynthesis, and all three involve breast tomosynthesis, which is usually appropriate for breast cancer screening and diagnosis:

• "Digital breast tomosynthesis diagnostic"
• "Digital breast tomosynthesis screening" 
• "Digital breast tomosynthesis short-interval follow-up"

Elsewhere, tomosynthesis is mentioned maybe a couple of times in the narrative discussion or literature search as part of the regular x-ray modality analysis (for example, here and here), but clearly it is not significant enough to deserve any attention as a specific imaging procedure indicated in specific diagnostic scenario.

The real problem is that the proposed Nanox.Arc cannot perform digital breast tomosynthesis, contrary to Nanox claims in March 2020 about no-squish mammography.  In its own mammography white paper, Nanox admits that breast tomosynthesis requires compression (squishing) and a completely different mechanical design, which makes scanning of other organs, such as lungs, impossible.

So here we have it.  According to the American College of Radiology evidence-based guidelines, the use of Nanox.Arc, as proposed, will not be "usually appropriate" under any clinical scenario.