If you want an investment to get to $1 million, you'll need a lot of patience. Buying and holding for not just years but decades is a strategy many of the world's most successful investors recommend, including billionaire Warren Buffett, who says, "All there is to investing is picking good stocks at good times and staying with them as long as they remain good companies."

Nano-X Imaging (NNOX 2.84%) has generated strong returns this year, but is it a good company worth holding in your portfolio for the long term? And can it be the type of investment that grows to $1 million in the future?

Why it might be a millionaire maker

Nano-X isn't a big stock today; its market cap is less than $900 million. The advantage of buying stocks at such low valuations is that if they succeed, there can be lots of upside and room for their valuations to get much bigger. Having even just a single successful product can be enough for a business that size to grow and generate strong returns for investors.

The company hopes that with its multi-source X-ray system, the Nanox.ARC, it might already be on the cusp of significant revenue growth. In May, the Food and Drug Administration granted clearance for the Nanox.ARC system, which includes the cloud-based infrastructure that it utilizes, the Nanox.Cloud.

The clearance allows Nano-X to begin marketing the products. The company expects the X-ray system to improve the accessibility of high-quality medical imaging in the U.S. and worldwide. Management says its system "has the potential to be a cost-effective and scalable imaging solution in healthcare settings that would otherwise be unable to deploy traditional medical imaging equipment."

In short, the X-ray system could be a game changer for many hospitals and other healthcare facilities. And if that turns out to be the case, the upside might be significant.

Even with its gains this year, analysts believe the stock of Nano-X can go even higher. Cantor Fitzgerald has set a price target of $30 for the healthcare stock, which is more than 90% higher than where it trades today. Price targets typically look at where analysts think a stock could go within the next year or so. In the long run, the investment can have even more upside.

Why Nano-X might struggle

The biggest obstacle for Nano-X stock is that its X-ray system still needs to prove that the business model works and can attract the demand level it would require to lead to meaningful revenue growth.

Nano-X wants to make its systems affordable and plans to use a pay-per-scan business model. That can certainly help the X-ray devices penetrate healthcare settings if the users know they won't have to pay a large lump sum to acquire them.

But it also means revenue may be slower to trickle in, and it may not be significant until Nano-X amasses a large user base -- assuming that it can. And time can be Nano-X's enemy since the company burned through $43 million in cash last year from its day-to-day operations, and that figure has been growing, as this chart shows:

NNOX Cash from Operations (Annual) Chart

NNOX cash from operations (annual) data by YCharts.

Now that Nano-X will likely ramp up operations as it markets and tries to place these X-ray devices, its costs will surely rise, which can significantly accelerate its rate of cash burn.

In at least the short term, while the company is building out its business and trying to acquire customers, it may be inevitable that Nano-X needs stock offerings to fund its operations. As of the end of March, its cash and investments totaled just $91 million, which doesn't provide a lot of runway for the business.

There's a high possibility that Nano-X will need to issue shares, and that could continue until it generates positive cash flow. 

You shouldn't expect Nano-X to make you a millionaire

If you were to invest $25,000 into Nano-X, which would be a lot for a relatively unproven healthcare company, you would need your investment to grow to 40 times its value to be worth $1 million.

Put another way, the company's valuation would need to skyrocket from roughly $850 million to a whopping $34 billion. The entire global medical-imaging market may be worth $56 billion by 2028, according to estimates from Fortune Business Insights. Nano-X would have to be a major player in medical imaging for it to likely get anywhere near a $30 billion-plus valuation.

It's not impossible for the company to reach that kind of valuation as growth investors can sometimes pay significant earnings and revenue multiples when they sniff out some fast-growing stocks. But Nano-X still has to prove itself, and with a pay-per-scan model, it can take a long time before the business generates profits and positive cash flow.

If you're comfortable with the risk, this can be a good stock to own, but I wouldn't put a lot of money into it or set expectations too high. It's far too early to tell if Nano-X will be successful.