= LhARA radiobiology; meeting: 27Nov25; 14:00 BST =

**ZOOM:** https://imperial-ac-uk.zoom.us/j/98220889714?pwd=SM90vOF7BKSXoU3mD9q7OwBQo4IVB3.1 

Attended: EM, JMcG, CW, DA, AFr, TP, AG, MB, MH, JP, RW, CD

== Meeting Notes == 

1. Minutes and actions:

2. Laser: RW \\
- RW: Explanation of the laser problem and the fix
 - That problem seems permanently fixed.

3. RCF: AFR, DA, CD \\
- Calibration
 - Rotation Issue
 - Rotating the films in the scanner can cause a ~30% change to the mean dose in a particular case. More generally causes a substantial difference.
 - Can combat by rotating the films each time we scan and always selecting the orientation that gives the highest mean pixel count
- Calculating Dose per Shot, Variation and Dose delivered to Cells
 - From RCF, average dose per shot of 0.61±0.25Gy (More data to be analysed)
 - Hard to spot a variation day to day
 - Variation in one showed a change after 8 films had been irradiated. Need to analyse the shots to get a better understanding of what this is
  - Robbie's suggestion is a defocussing laser spot effect
- Flatness and Uniformity of Dose
 - Average CV: 15.1±2.5%
 - Average Flatness in X: 26.4±5.5%
 - Average Flatness in Y: 29.6±4.7%
 - Beam is too non-uniform still
- Sim comparison
 - CV: 17%
 - Moving the Copper closer would bring CV down to 9% and the mean dose would also fall by 45%

4. Bio: EM, JP \\
- EM: Summary of Experiment
Dry Run
- Seeding density test
FaDu gave a plating efficiency of 40?%
- Marie Boyd update
 - Comet analysis
Alive dead stain can be done after a couple of hours?
That depends on the dose received to how to wait
- Collect pellets and do a western blot test for a rough idea
 - Could not tell between a 2 and 4Gy
H2X
-There is a way to select cells from all the same area. Though there is the issue that there are not enough cells then.

- IF might give an idea of hotspots
- x-ray irradiate with a known dose to do a comparison
- Marie will do a comet assay
- Plan for staining and delivery back to Birmingham 

- Move things to Marie's lab
- Can also do some control irradiations at Marie's as well


- From the colonies, no growth in the controls either
- Microscope is not great, so Marie can take their one to SCAPA
- Could be the microscope that means cannot see any cells
- Marie can do the staining check on Friday but will do on Monday
- The cells were dried out by 50%, incubator felt very hot and humid. Put a thermometer in it to check

5. Future: \\
- Current Problems:
 - Clear Communication of Requirements
 - RCF to Dose Procedure
  - Alfredo and Diaza are piecing together a protocol document to standardise how we complete this procedure
  - The rotation issue is taken into account
  - Diaza in favour of scanning at lower resolution to speed it up
 - Uniformity not good enough
  - Place the Copper scatterer closer
  - Results need to analysed
 - Shot-to-shot variation
  - Include a piece of RCF in front of the cells (Ideally delaminated but not possible to calibrate before the next visit)
   - Need to sim what the LET would be for our energy range into the cells with the RCF in place
  - Longer-term investigate an on-beam diagnostic
  - Another option is to find a correlation between the RCF mean dose and one of the laser diagnostics that the team already gathers

- Discussion of when to use the rollover days 
 - Plan to use Wednesday, Thursday and Friday next week
 - If good, then use the 3 days to do more cell irradiations
  - Emma will send the dishes up tomorrow 
 - If not work on more beam diagnostics and improving it to complete cell irradiations, tackling either uniformity or shot-to-shot variation

- IPAC abstract submission?
 - No takers and a belief that we should wait until we have a slam dunk result
 - Note: LhARA will have a general submission that will mention PoPLaR
- Book a longer discussion to analyse all the results and define a plan for the future
 - Not discussed

6. DoNM 
- 11th Dec

7. AoB
- Congratulations Dr Melia!!!




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