Reading CT with Luminor

2Getting started

Start Luminor

1. Open a PowerShell window in the Claude-Radio folder.
2. Run .\start.ps1. It uses the DICOM Anaconda environment when it exists, starts the server on port 8770 and opens your browser after two seconds.
3. Leave the PowerShell window open while you work. Closing it stops Luminor.

Luminor runs at http://127.0.0.1:8770/ in Chrome, Edge, Safari or Firefox. Options:

Open a series

The library on the left lists every series in the data folder. Click a row to open it. Luminor first reads the DICOM files (a few seconds), then loads the volume into the browser. A progress card shows both steps.

• Search filters by series ID. Type any part of it.
• All · Cancer · No cancer filters by the dataset label. Rows show a red Cancer or grey Clear tag.
• Image counts appear as soon as the folders have been counted. Until then a row shows Counting….
• The next time you start Luminor, it reopens the last series you viewed.
• Exams with several series (bone and soft-tissue reconstructions, a coronal series, MRI sequences…) show a series bar above the images: ‹ Previous and Next › (or P / N) step through the series, the drop-down jumps to any of them, and the counter shows where you are (for example 2 / 3). Luminor keeps the same anatomical position when you switch, or the nearest slice if the other series does not cover it.
• Luminor displays CT and MRI volumes (including compressed DICOM and multi-frame MRI) and 2D images: ultrasound images and cine loops, screenshots, scout views. 2D images are shown one by one with the same tools (scroll, zoom, brightness/contrast, measurements), but without reformats, slabs or orientation letters. Lengths are in mm when the image is calibrated, otherwise in pixels.
• An exam's PDF reports appear as Report (PDF) buttons in the series bar and open in a new tab.

Change the images folder

The top of the library shows the current Images folder. To open another folder of medical images at any time:

1. Click Change… next to the folder name.
2. Click Browse… to pick a folder with the Windows folder picker, or paste its path (File Explorer → right-click the folder → Copy as path), then click Open folder.
3. Luminor checks that the folder contains DICOM series, closes the open studies, reloads the library and opens the first series.

Choose the folder in which each sub-folder is one series of .dcm files. If you choose a single series folder, Luminor opens its parent folder. A labels CSV in or just above the folder is picked up automatically. Your DICOM files are only read, never modified.

Images on Google Drive

You can also paste the link of a Google Drive folder (for example https://drive.google.com/drive/folders/…) in the same field and click Open folder. The folder must be shared with “Anyone with the link”. Luminor downloads it, with its sub-folders, to this computer, showing the progress, then opens it. Files already downloaded are kept, so opening the same link again is quick. Closing the sheet stops the download.

Interface language

The EN / FR button (with a globe) in the toolbar switches the whole interface between English and French without reloading the study: labels, help, findings, the report draft and the on-image text. Luminor remembers your choice; on first launch it follows the browser language.

In French, Luminor follows French conventions: UH for Hounsfield units, decimal commas, C/L (centre/largeur) for the window and D/G (droite/gauche) instead of R/L for orientation. Finding names stay exactly as you typed them.

3The interface

• 1Library: series list, search, label filter and the compare button.
• 2Toolbar: layout, plane, tools, cine, help, panel toggles.
• 3Viewer: one to three image panes. The active pane has a blue outline.
• 4Overlay: plane, image number, position, window, slab, HU and zoom.
• 5Status bar: HU, voxel and patient coordinates under the cursor.
• 6Inspector: window, slab, cine, findings and series details.

The toolbar

Reading the overlay

4Scrolling & cine

Scrolling through the stack is the heart of CT reading, so it is always on the mouse wheel, whatever tool is selected.

Set the cine speed (2–40 images per second) with the Cine slider in the inspector. Cine and the keyboard act on the active pane, the one under your mouse, which has a blue outline.

5Window & level

CT images contain far more grey levels than a screen can show. The window chooses which Hounsfield range is displayed: the centre (level) sets the middle grey and the width sets the contrast.

Presets

Adjust freely

• Right-drag on any image, with any tool selected. Drag left/right to narrow or widen the window. Drag down/up to raise or lower the level: the image gets darker as you drag down. The drag speed adapts to the current width, so fine adjustments stay easy in narrow windows.
• Or select the Window/level tool (W) and use the left button.
• Or type exact values in Center and Width in the inspector.
• I inverts the grey scale.

The window applies to every pane, including the comparison study, so both are always displayed the same way.

6MPR & crosshair

Multiplanar reconstruction (MPR) rebuilds coronal and sagittal images from the axial stack, with correct physical proportions and the head at the top.

1. Choose MPR in the layout control, or press L.
2. Select the Crosshair tool (X). Click or drag on any pane to place the crosshair. The other two panes jump to that point.
3. Scroll in any pane. The matching line moves in the other two.
4. Double-click a pane to enlarge it. Double-click again to return to three panes.

The crosshair lines take the colour of the plane they represent: blue for axial, green for coronal, orange for sagittal.

Zoom and pan

• Ctrl + wheel (or a trackpad pinch) zooms around the mouse position, from 25 % to 1200 %.
• Middle-drag pans with any tool. The Pan (H) and Zoom (Z) tools do the same with the left button.
• R resets zoom and pan.

7Measurements

HU probe

Move the mouse over any image. The overlay (bottom left) and the status bar show the Hounsfield value of the voxel, its indices, and its patient coordinates in millimetres (LPS convention: +X is the patient's left, +Y posterior, +Z superior). The probe always reads the original voxel, even when a slab is displayed.

Length

1. Select Length (M).
2. Drag from one edge of the structure to the other. The distance in millimetres updates as you drag.
3. Release to save it as a finding.

Lengths use the true pixel spacing of the plane, so they are also correct on coronal and sagittal reformats, where slice spacing and pixel size differ.

Ellipse ROI

1. Select Ellipse ROI (E).
2. Drag the bounding box of the ellipse over the region.
3. Release. Luminor shows the mean ± standard deviation, minimum / maximum HU and the area.

Markers

Press B (or the Marker button) to drop a marker at the crosshair position. It records the HU value at that point. This is useful for flagging a lesion you want to come back to.

Selecting and deleting

Measurements appear only on the image where they were drawn. Click one (with the Crosshair, Length or Ellipse tool) to select it. It turns light blue. Press Delete to remove the selected finding, or Esc to deselect it or cancel a drawing.

8MIP & slabs

A slab combines several adjacent images into one, centred on the current image. Choose the mode in the inspector's Slab card, or press T to cycle through them.

Set the thickness from 2 to 40 mm with the slider or + / −. The overlay shows the thickness actually used, which is rounded to a whole number of slices. Slabs work in every plane and in every pane.

9Comparison

1. In the library, hover over the series you want to compare with and click the ⧉ button on its row.
2. Luminor switches to the Compare layout. The comparison starts at the same relative height in the body as your current image.
3. Scroll either pane. While Linked is on, the other follows by the same distance in millimetres, even if the two studies have different slice spacing. Zoom and pan are mirrored too.

Aligning two studies

Patients are never positioned identically, so align the studies on an anatomical landmark (for example the carina or a lesion) once:

1. Press K to unlink.
2. Scroll each pane to the same landmark.
3. Press K again. Luminor records the offset between them, and they now scroll together at matching levels.

Changing the plane re-centres the comparison study, so re-align after switching between axial, coronal and sagittal. Measurements and markers are made on the current study (left pane).

10Findings & reports

Working with findings

• Rename: click the name, type (for example "RUL nodule"), and press Enter. The name also appears on the image.
• Go to: click a finding to jump straight to its image. The crosshair centres on it, and Luminor switches plane if needed.
• Delete: hover over a finding and click the trash icon, or select it and press Delete.
• Findings are saved automatically on your computer, one file per series in Claude-Radio/data/findings/. They come back when you reopen the series.

Report draft

Click Report in the Findings card. Luminor writes a draft with the series details, a technique line, a numbered list of your findings with values and locations, and an empty Impression section. Complete the contrast phase, protocol and impression yourself. Then click Copy to paste it into your report, or Download .md to save it.

Key images

Key image saves the active pane as a PNG, including measurements, the overlay text, orientation letters and a "research use only" watermark. The file name contains the series, plane and image number, for example key-image_0015ceb8_axial_98.png.

11A reading routine

A suggested systematic routine for a chest CT. Adapt it to your own practice.

1. Lungs: press 1, scroll from apex to base, then repeat with a 10 mm MIP (T) for nodules. Use MinIP for airways.
2. Mediastinum: press 2. Check the heart, great vessels, oesophagus and lymph node stations. Measure nodes on their short axis (M).
3. Bones: press 3. Read the spine in sagittal (S) and the sternum and ribs on axial and coronal images.
4. Upper abdomen: press 4 for the liver, then check the adrenals, kidneys and spleen.
5. Characterise: confirm each finding in MPR, measure it, and place ROIs to check density (fat, fluid, soft tissue, calcium).
6. Compare: open the prior study, align it, and check whether lesions are new, stable or changed.
7. Report: name your findings, save key images, then open Report and complete the impression.

12Keyboard & mouse

Press ? (or /) in Luminor for this list. Shortcuts are ignored while you are typing in a text field. Click an image to return to the viewer.

13HU reference

Typical unenhanced CT values, as orientation for the probe and ROI tool. Values vary with scanner, protocol, contrast and noise.

14Troubleshooting

15Privacy & limitations

• Local only. The server accepts connections from this computer only (127.0.0.1). Images and findings never leave it. The only outside request is for the Inter font from Google Fonts; without internet, Luminor uses your system font.
• Not for diagnosis. Luminor has not been validated or certified as a medical device. Use it for research, teaching and exploration.
• Data. Luminor reads CT series stored as folders of DICOM files. It does not connect to a PACS, and it does not support multi-frame or compressed formats that pydicom cannot decode.
• Geometry. Reformats assume a standard axial acquisition with evenly spaced slices, which is true of typical chest CT. Check the orientation letters on unusual series.
• Reports. The report draft lists only what you measured. Clinical context, technique details and the impression are always yours to write.