DICOM viewer for iPad · iPadOS 18 or later

See beyond the slice.

For radiologists, trainees and teachers. Open CT and MRI studies on your iPad. Reformat them in any plane, turn a CT into a 3D model for AR or a printer, and teach with notes, saved slides and recorded lectures.

No account, no analytics, no cloud. Your images stay on your iPad.

Download on the App Store Sample study What it is not
voXel on iPad: a volume render of a CT angiogram of the head and neck, bone in ivory and vessels in red.

Multiplanar reformats

Slice in any plane, including oblique.

A stack of slices is a volume, so it can be cut in any plane. voXel follows the geometry stored in the file, including a tilted gantry.

Below is a real chest, abdomen and pelvis CT, resliced in your browser with the app's own arithmetic and controls. It is reduced for the page; the full study is under Try real studies.

Axial · slice 136 of 270

Drag to use the tool · wheel scrolls · pinch or ctrl-wheel zooms · two fingers move · double tap resets

firstthrough the volumelast
  • Volume169 × 125 × 270
  • In-plane spacing2.65 mm
  • Slice thickness2.50 mm
  • WindowL 40 · W 400
  • SourceLNQ case_0164, TCIA

Spacing matters. These voxels are 2.65 mm across and 2.5 mm deep, and in the original they were 0.88 mm by 2.5 mm. voXel scales every plane by the real spacing, so a coronal cut keeps the patient's proportions.

Axial, coronal and sagittal reformats of a head and neck CT in three panels, with a linked crosshair.
In the app: axial, coronal and sagittal together, with a linked crosshair.

Three dimensions

A model you can hold, or print.

Render the whole CT in 3D, cut it into layers, and build the layers into a model for AR or a printer.

  1. 1Choose. Tap Bone, Vessels, Heart, Lungs, Airway, Colon, Skin or MIP, with more under More. On CT, a preset finds what it shows: the vessel presets find the aorta, or a carotid on a head and neck CTA, and take the bone out; Airway, Lungs and Colon find the air inside the body. A line over the render says what was found, so you can check it. Stack up to eight layers in one render, each in its own colour and opacity.
  2. 2Cut. Tap Keep on what you want, Remove on what you don't, or draw a loop with Lasso. Edge moves where the preset starts, and Auto puts it back. Undo takes back a cut; hold it to restore everything. B minus A makes a layer of one less another.
  3. 3Print. Tick the layers, set detail, smoothing and hollowing, and build. Fill marrow keeps a vertebra solid. Each layer becomes a closed mesh in its colour. Place drain holes, view it in AR, save it with the study, or export STL, OBJ, 3MF or USDZ.
Detail

Start at quarter

Quarter detail is quickest and suits AR and printing. Half shows more. Full makes very large files.

Layers

Open the skull, keep the vessels

Pick the bone layer and lasso it alone. The vessels stay whole inside it.

The 3D screen with Bone chosen from the presets along the top, a skull and neck vessels in the render, and the Adjust tab below.
1. Choose a preset.
A skull render with a lasso loop drawn beside it to cut a stray piece away.
2. Trim it with the lasso.
A pelvis and the leg arteries as two layers, Vessels and Bone, each with its own eye.
Vessels and bone as two layers.
A bone and vessel model standing on a table in AR.
3. Stand it on the table in AR.

Teaching

Ready when the class is.

Write notes beside the image, record the lecture into them, group cases into study sets, lay out the steps through each, and keep the best slices as saved slides. Open the iPad and teach.

My Notes

Every note in one place

Notes, cases and pins from every study in one table, sorted by name, kind, modality, diagnosis or date. File them in folders, tag them, and give a case its status, subspecialty and certainty. A case note keeps the history, findings, diagnosis and teaching points under seven headings. A note outlives its study. Save a view of the table, with its search and filters, to come back to.

Lectures

Record the talk into the note

Tap the mic in a note to record a lecture; a red dot and the time show while it records. Ask the lecturer first. The recording stays on the iPad. Transcribe Pro turns it into text on iPadOS 26 with Apple's speech recognition, on the iPad, knowing radiology words. Select a misheard word to fix it.

Study sets

Cases, grouped and named

A set lists cases in your order, with a note for the session. A case is the slices you pick from a series, copied into the set with the patient's name, IDs and dates written over, so it stays when the study is deleted. Text burned into the image stays. Hide patient details with one tap before you project.

Guided steps

Through the case, view by view

Save the views you want to show, each with its series, slice, window and a line of text. The arrows take the class from one to the next.

Note pins

Notes on the image

Drop a pin on a finding and write a note. Link it to a web page, or to a pin on another case, and tap through a case step by step.

Sequence notes

A notepad beside the image

Tap Notes and a lined page slides in beside the image, which you can still scroll and window, or fill the screen with it. Type, or write with the Apple Pencil in five colours. Pin this slice puts a link in the note that goes back to that sequence and slice, and a PDF can be attached from Files. Share it as an A4 PDF.

Saved slides

A library of slices

Save a slice with its marks into a named deck and write a note under it. The copy carries no name, ID or date, though a name burned into the pixels stays. Reorder the slides and export the deck as one PDF, or as an Anki deck with a card for each image.

Angiography

Arrows on a run

Label a vessel, point an arrow or trace a stenosis on an angiography run. Each mark stays on its own few frames, so the run scrolls clear of it.

My Notes: a table of notes and cases with kind, modality, subspecialty, status and date, the diagnosis hidden.
My Notes, with patient details hidden.
A deck of saved slides, each with its window and a note.
A deck of saved slides.
One saved slide: an axial MR slice of the lumbosacral spine with a marked finding.
One slide, with its mark.
A cerebral angiogram with an arrow and the note: what is this artery?
A question on an angiography run.

Everything it does

The feature list.

All of it is in the app. A Pro label marks what voXel Pro adds; everything else is free.

Viewing

Window, level and moving through

  • Ten CT presets for the modality, invert, or an exact centre and width
  • The file's own window and VOI LUT Function are honoured
  • Scroll by drag, trackpad or keyboard; cine, zoom, pan, rotate and mirror
  • One, two or four panels, scrolling together
  • Tag inspector, and seven icon styles
  • Show performance: CPU, memory, frame rate, power and heat
Teaching

Sets, notes and steps

  • My Notes: every note and case in one table, with folders and tags
  • Saved views of My Notes Pro
  • Record a lecture into a note, and play it back
  • Transcribe a recording on the iPad, iPadOS 26 Pro
  • Study sets of cases, in your order, with a note for the session
  • A case is the slices you pick, copied and anonymised
  • A case note under seven headings, history to teaching points
  • Guided steps, each keeping its series, slice and window
  • Notes outlive the study they were written on
  • Hide patient details with one tap
Reformats

Multiplanar Pro

  • Axial, coronal, sagittal and oblique
  • Thick slab as mean, MaxIP or MinIP
  • Linked crosshair and Locate
Three dimensions

Layers and printing Pro

  • Up to eight layers, each with its own preset, colour and opacity
  • Presets find the aorta, a carotid, the airway, the lungs or the colon, and say what they found
  • Bone taken out for vessels on CT, and the table taken away
  • Keep, Remove, Lasso and the brush, with Undo
  • B minus A, and the layers of a saved model loaded again
  • Build for printing: smoothing, hollowing, fill marrow, drain holes
  • Wall thickness, and the outline checked against the slices
Three dimensions

Volume rendering Pro

  • Shaded, MaxIP, MinIP or average
  • Airway, lungs and colon, with air outside the body removed
  • Clean up specks and noise
  • Hue and tint for each preset
  • View in AR, and save it with the study, layers and all
Marks

Measure, annotate, keep

  • Distance, angle, Cobb angle, area and Hounsfield units Pro
  • Labels, arrows and freehand, on angiography too Pro
  • Five note pins, with a list of them all; unlimited Pro
  • Three sequence notes, typed or in Apple Pencil; unlimited Pro
  • Ten saved images in Saved slides; unlimited Pro
  • Saved slides or a note as PDF, and Anki flashcards; PDF without footer Pro
In and out

Getting studies across

  • Folder, ZIP or RAR from Files, USB-C or AirDrop
  • Scan on a hospital CD? Copy it to a USB-C drive first
  • Send from a desktop browser on your Wi-Fi, encrypted Pro
  • PNG with a small footer
  • JPEG, GIF and MP4 Pro
  • STL, OBJ, 3MF, USDZ and DICOM, reduced to size if you like Pro
Encodings

What it reads

  • CT, MR, X-ray, mammography, ultrasound and angiography
  • Uncompressed, deflated, lossless and baseline JPEG, JPEG-LS and RLE
  • Colour, palette and multi-frame studies
  • Not yet: JPEG 2000
Free and Pro

What it costs

  • Free: everything without a label, for as long as you like
  • Pro: yearly with a 7-day free trial, or once for life
  • Buy once, and it carries to your other iPads

Roadmap

What comes next.

Planned, not promised. Teaching comes first, in this order. A dashed box is built and comes out with the app on 10 November; a box is ticked, with the date, when the feature reaches the App Store.

Next · teaching from the iPad
  • Case notes. History, findings, diagnosis and teaching points, written once for each case.Built, out 10 Nov
  • Guided steps. Walk through a case view by view, with Next and Previous.Built, out 10 Nov
  • Sequence notes. A lined notepad beside the image, typed or in Apple Pencil, with links back to the slice.Built, out 10 Nov
  • Layers and 3D printing. Tap to tune, up to eight layers, and a model built from them for printing.Built, out 10 Nov
  • My Notes. Every note and case in one table, with folders, tags and saved views.Built, out 10 Nov
  • Lecture recording. Record a talk into a note, and transcribe it on the iPad.Built, out 10 Nov
  • Flashcards. Export a notebook as an Anki deck, one card per saved image.Built, out 10 Nov
  • Coronary arteries. Trace an artery between taps, see it straightened with a cross-section you can turn, and show the heart with the traced arteries solid.Built, in testing
  • Case quiz. The story a piece at a time, findings marked on the slices, answers compared at the end.
  • Quiz files. Send a quiz to students for their own iPads. It carries its own images, with no patient details.
  • Presenter mode. A clean audience view on a connected display, recorded to video with your voice.
Being considered
  • Anonymised DICOM export. A published profile, with IDs replaced consistently across a study.
  • JPEG 2000. When enough people ask for it.
  • iPhone. If the iPad version shows people want it.

Scope

What it is for, and what it is not.

For

  • Reference and review of studies you already have
  • Teaching, with no login or portal
  • Showing patients their own scans
  • 3D models for AR and printing

Not for

  • Primary diagnostic interpretation. An iPad display is not calibrated to the DICOM Part 14 standard
  • Reporting. It writes and signs nothing
  • PACS. It does not query or retrieve

Networking. The app's only networking is a small web server that runs while Send from a desktop is open. It answers only to the code on screen, over an encrypted connection, and it receives files. Nothing is sent out.

The Send from a desktop sheet, showing the address to open, the certificate fingerprint and the files received.
Send from a desktop: the address to open and the fingerprint to check.

Try real studies

A brain MRI and a body CT to open in voXel.

The sample study is a phantom. For real scans, download a series from a public research archive. The archive removed each patient's identity before publishing.

Brain MRI. A 3D T1-weighted MRI with contrast, taken before tumour surgery: 151 slices, a 6.7 MB ZIP. The archive cut the face from the images.

Download the brain MRI

Chest, abdomen and pelvis CT. A contrast CT from the base of the neck to the pelvis: 270 slices of 2.5 mm, a 66 MB ZIP. Reformat it coronally or along the spine, and switch between lung, soft tissue and bone windows. It stops below the face, so there is no face to remove.

Download the CT

The files come from The Cancer Imaging Archive, not from this site. Save one to Files, then tap + in voXel and choose the ZIP. Each is shared as the archive publishes it, with its licence file inside, under CC BY 4.0 and the TCIA data usage policy. Neither the authors nor the archive endorse voXel.

Credits

MRI data. Juvekar P, Dorent R, Kögl F, Torio E, Barr C, Rigolo L, Galvin C, Jowkar N, Kazi A, Haouchine N, Cheema H, Navab N, Pieper S, Wells WM, Bi WL, Golby A, Frisken S, Kapur T. The Brain Resection Multimodal Imaging Database (ReMIND), version 1 [dataset]. The Cancer Imaging Archive, 2023. doi:10.7937/3RAG-D070. Brigham and Women's Hospital, Boston. Series: patient ReMIND-051, preoperative 3D_AX_T1_postcontrast.

MRI publication. Juvekar P, Dorent R, Kögl F, Torio E, Barr C, Rigolo L, Galvin C, Jowkar N, Kazi A, Haouchine N, Cheema H, Navab N, Pieper S, Wells WM, Bi WL, Golby A, Frisken S, Kapur T. ReMIND: The Brain Resection Multimodal Imaging Database. Scientific Data 11, 2024. doi:10.1038/s41597-024-03295-z.

CT data. Idris T, Somarouthu S, Jacene H, LaCasce A, Ziegler E, Pieper S, Khajavi R, Dorent R, Pujol S, Kikinis R, Harris G. Mediastinal Lymph Node Quantification (LNQ): Segmentation of Heterogeneous CT Data, version 1 [dataset]. The Cancer Imaging Archive, 2024. doi:10.7937/QVAZ-JA09. Tumor Imaging Metrics Core (Massachusetts General Hospital, Dana-Farber Cancer Institute and Brigham and Women's Hospital, Boston). Series: case_0164. The reformat demo above uses it reduced to 2.65 mm across and rounded to 4 HU.

Archive. Clark K, Vendt B, Smith K, Freymann J, Kirby J, Koppel P, Moore S, Phillips S, Maffitt D, Pringle M, Tarbox L, Prior F. The Cancer Imaging Archive (TCIA): maintaining and operating a public information repository. Journal of Digital Imaging 26(6):1045-1057, 2013. doi:10.1007/s10278-013-9622-7.