A Turkish viewer-factory DICOM app: on medical grossing charts in 40 countries, only China is actually paying

In 2026 October 13, someone on the China App Store gave "DICOM Medical Imaging Viewer - MesDICOM" one star, writing: "What is this junk, my free software works better than this, what did I buy!!?" That review tells two things: someone got a CT or MRI scan from a hospital, searched "DICOM" on their phone, found this app, paid on the spot, and then regretted it. Three weeks later, in November 5, the app reached #4 on Panama's medical grossing chart, yet it had zero ratings in Panama. This article covers what it is, how much of the chart numbers are real, where the money comes from, how crowded the space is, and whether you should follow it.

What it is: viewing your hospital scans on a phone

MesDICOM is a medical imaging viewer for iPhone and iPad. The first line of the China store page reads: "Open files, folders, ZIP archives, or individual DICOM files copied from an imaging disc to view exam images on your device." It covers the features fairly thoroughly: window width and level adjustment, 30 presets, multiplanar reconstruction in axial, coronal, and sagittal views, 3D volume rendering, measurement of distance, angle, and ROI, PDF export, and connection to DICOMweb servers. Images stay on the device, with no sign-up. The store page also clearly states that it is "not a medical device" and must not be used for diagnosis.

It's made by ONNEX YAZILIM in Eskişehir, Turkey, released in Aug 24, updated in Oct 16 to 1.2.5. The company has 12 apps under its name, mostly "viewers for some file type": WristDocs for reading PDFs on Apple Watch (399 ratings), Mes3D for viewing STL 3D models (released April 2026), and now one for DICOM. 3D rendering, file import, and the subscription paywall are all off-the-shelf. Swap the file format, add 13 languages, and you have a new app.

Free to download; Pro is a subscription: weekly $3.99 or $5.99, annual $19.99 or $29.99, lifetime $79.99.

What's behind the "40-country grossing chart" claim

From Oct 28 to Nov 6, it appeared on the charts of 31 to 41 countries each day, reaching the medical category charts of 65 storefronts in total. That sounds big, but checking the rating counts changes the picture. Its best rankings were Panama #4, Slovenia #4, Ecuador #6, Egypt #7, Iceland #13, and Singapore #20, and all of those storefronts had 0 ratings.

Panama's trend tells the story best. From 10-28 to 11-03, it hovered between #52 and #184 on the local free medical chart; on 11-05 it suddenly jumped to #4,11-06 and #8 on the medical grossing chart. A zero-rating app breaking into the top 5 overnight likely means a handful of subscriptions (inference). The bar for small-country medical grossing charts is nearly zero.

Strip out those storefronts and the volume is tiny: about 25 ratings worldwide in total, with 0 to 3 new ratings per day. The US storefront has 6 ratings and has never charted. The UK, Germany, and Japan only show up occasionally, around #63 to #196 on the medical grossing chart.

China is the only market with real volume. Ratings rose from 10-28 to 7 to 11-06 to 12, averaging 4.0 stars. It stayed on the medical grossing chart for 10 consecutive days, ranking between #35 and #86, mostly around #35 to #57. 11-06 It ranks #50, with "Piyo Log" ahead and "Discover the Human Body 3D" and AMBOSS behind it. In money terms, that's probably tens of dollars a day (estimate, unverified). The Google Play version launched in Sep 23, and as of 11-06 it had 1,331 installs.

Where users come from: search and "Open with"

We can't find any promotion of it anywhere: zero mentions on X in 90 days, no related TikTok videos in search, and no media or forum posts. It doesn't show up in the Meta, TikTok, or Google ad libraries (those cover only part of the market, so absence doesn't mean no spend; whether it runs Apple Search Ads is not visible from outside).

That leaves two routes, both inside the iPhone system:

1. Store search. The China store name is simply "DICOM Medical Imaging Viewer," with the keyword at the front. Titles in 13 languages follow the same approach. People searching "DICOM" know exactly what they want: they have a scan and want to view it right now.
2. File association. A patient copies the disc files to their phone, or gets a ZIP, and when they tap it iOS lists MesDICOM under "Open With". It even recognizes DICOM files with no extension. The mechanism is confirmed. How many people it brings in is unknown.

So the user is an anxious patient or family member. They just got the scans, have no computer nearby, and the hospital disc won't open on their device. They pay weekly for "see it right now", and once they've looked, they don't need it anymore. It's a one-time transaction with little retention. The only three written reviews in the China store are all one-star ("cumbersome", "not usable", plus the one at the top). The average rating is 4.0, which suggests people who only rate and don't write do like it more, but the sample is too small to show either way.

Who it's competing with

Search the App Store by name for DICOM, PACS, image viewer, medical imaging, and you'll find 100 apps. Only a few established ones have real scale. 2026 years on, a dozen or so newer ones have appeared:

The last row matters most for the China store. More and more hospitals just hand out a QR code, and a phone scan opens the images, so discs are used less and less. MesDICOM's only paying market is shrinking in demand.

What it does better than others, and whether that's enough

Feature-wise it really is more complete than most 2026-year-old newcomers. It has MPR, 3D, and DICOMweb, and is close to IDV. But patients searching for "DICOM" can't tell these features apart from the store page. What actually decides their download is the title, the icon, and the ranking. Its real difference is distribution: localized titles in 13 languages, plus file association. Both can be learned in a weekend. Ossidex's Chinese name uses the same approach, and it did so earlier.

If it were you

The verdict: don't go after DICOM as a format. A dozen-plus players have already crowded in, and the leader has reputation. What's worth copying is the "file viewer factory" behind it: a specialized format, multilingual keyword titles, the system Open With menu, and a subscription wall shown on first open.

Who it fits: a small team that already has code for file import, rendering, and a subscription paywall, can ship a new app a month, and lives off long-tail store search.

Who it doesn't fit: anyone who wants to build a brand or long-term subscriptions from one app. These users leave once they've seen their scans, and refunds and bad reviews pile up. Medical review is also stricter. It's also not for building pro reading software for doctors. That belongs to OsiriX and Falcon, and it requires credentials and hospital channels.

How to do it: look for professional formats that ordinary people end up with but can't open. DICOM, STL, and EPUB are already taken, so look at DWG, GPX, specific camera RAW formats, and various engineering or survey files. Search the format name on the App Store and check whether the top ten are just one or two old apps with few ratings and no update in the past year. First make it open and display files correctly, start each localized title with the format name, register as a system Open With handler, and only show the paywall after the first successful open.

How to get users: skip social media. Rely on store search and multilingual titles, plus file association. To judge whether it's really making money, look only at large-country or high-barrier charts (for example, the China-store medical Top Grossing, places 35 to 60), and ignore rankings in small-country stores.

When to move: for DICOM alone, the window has already closed. The first half of 2026 was already crowded. Other formats have no clear deadline. But AI-assisted coding makes building a viewer cheaper every day, and once a format is claimed, later entrants can only fight over the leftover long tail.

What would prove this wrong: if by December MesDICOM drops out of the top 100 in the China-store medical Top Grossing and its ratings stay in the low dozens, it means even this China-store revenue is short-lived, and each app in the "viewer factory" earns too little to be worth building. Conversely, if it holds steady on the Top Grossing charts in large markets like the US or Japan, the approach is worth more than we estimated, and the grade should go up.