Radiotherapy/Experimental Runs/2022-07-26
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Second run
Replaced plastic blocks from first run with new un-irradiated plastic blocks, but using same green scintillator sheet.
Second experimental measurements with Cyberknife at Birmingham. Green scintillator thin sheet measurements only.
Setup
Schematic
Photos of setup
(Inside pelicase, outside pelicase, collimators, through pelicase window)
Pre-data Taking Information and Notes
- Used 2mm thick green scintillator sheet
- 53cm from lens to sheet
- Check camera in focus with ruler on the sheet
- Near/Far limit of focus 49.4cm 57.1cm calculated using https://dofmaster.com/dofjs.html
- Pelicase on couch
- Scintillator blocks aligned to laser cross hairs
- 785 mm source to surface distance suitable for output factor/PDD/profile measurements.
- Room lights out and pelicase window open.
- Check optical axis aligned with top surface using crosshair in the image analysis.
- Arrived at hospital at 11am, finished data taking at 5pm
Data Taking
- All images taken with Nikon D7000, 20mm lens, f/2.8, 400ISO
- Used camera control pro 2 app
- Image of ruler taken at sheet for pixels to mm conversion
- 5 images taken at each collimator size with 1 background image each.
- Change exposure time until near max saturation - get's best bit depth
- View data analysis here
First run
| With scintillator sheet | |||
|---|---|---|---|
| Collimator Size (mm) | Exposure (s) | Image | Comments |
| 5 | 30 |
| |
| 7.5 | 20 |
| |
| 10 | 15 |
| |
| 12.5 | 10 |
| |
| 15 | 8 |
| |
| 20 | 8 |
| |
| 25 | 6 |
| |
| 30 | 6 |
| |
| 35 | 5 |
| |
| 40 | 4 |
| |
| 50 | 3 |
| |
| 60 | 3 |
| |
| No scintillator sheet | |||
|---|---|---|---|
| Collimator Size (mm) | Exposure (s) | Image | Comments |
| 60 | 3 |
|
Can see green discolouration caused by previous irradiations. Blocks must have been rotated by 90 when re-assembling |
Second run
Replaced plastic blocks from first run with new un-irradiated plastic blocks, but using same green scintillator sheet.
| With scintillator sheet | |||
|---|---|---|---|
| Collimator Size (mm) | Exposure (s) | Image | Comments |
| 5 | 30 |
| |
| 7.5 | 20 |
| |
| 10 | 15 |
| |
| 12.5 | 10 |
| |
| 15 | 8 |
| |
| 20 | 8 |
| |
| 25 | 6 |
| |
| 30 | 6 |
| |
| 35 | 5 |
| |
| 40 | 4 |
| |
| 50 | 3 |
| |
| 60 | 3 |
|
Green discolouration probably from scintillator sheet. |
| No scintillator sheet | |||
|---|---|---|---|
| Collimator Size (mm) | Exposure (s) | Image | Comments |
| 5 | 30 |
| |
| 7.5 | 20 |
| |
| 10 | 15 |
| |
| 12.5 | 10 |
| |
| 15 | 8 |
| |
| 20 | 8 |
| |
| 25 | 6 |
| |
| 30 | 6 |
| |
| 35 | 5 |
| |
| 40 | 4 |
| |
| 50 | 3 |
| |
| 60 | 3 |
| |
