Radiotherapy/Experimental Runs/2022-09-07

Third experimental measurements with Cyberknife at Birmingham. Green and blue scintillator thin sheet measurements with measurements of green radiation damage.

Setup

Schematic

Photos of setup

Pre-data Taking Information and Notes

• Used 200mmx200mmx2mm green or blue scintillator sheet polystyrene base sandwiched by two 200mmx200mmx50mm polystyrene clear plastic blocks
• 53cm from "phi" symbol on camera to sheet
• Checked camera in focus with ruler in front/back and middle of two blocks.
• 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 closed by 1mm pelicase material.
• Check optical axis aligned with top surface using crosshair in the image analysis.
• Used shims to level top surface of plastic blocks and scintillator sheet

Camera settings

• Focal length 20mm
• lens focus distance – 0.5 (500mm)
• 53cm focal plane (phi on camera ) to sheet
• f-number 5.6

Data taking

Plan

• Take photos of blue sheet with blocks starting from 60mm collimator size to 5mm.
• Remove blue sheet – repeat measurements
• Use new set of blocks and blue sheet - repeat measurements

Blue scintillator sheet
Collimator Size (mm)	Exposure (s)	ISO	f-number	File no.	Comments	Image
60	10	400	5.6	69-73
50	10	400	5.6	74-78
40	13	400	5.6	79-83
35	15	400	5.6	84-88
30	15	400	5.6	89-93
25	20	400	5.6	94-98
20	25	400	5.6	99,101-104
15	30	400	5.6	106-110
12.5	30	400	5.6	111-115
10	30	400	5.6	116-120
7.5	30	400	5.6	121-130
5	30	400	5.6	131-140
60	4	400	5.6	161-165
60	5	400	5.6	166-170
60	6	400	5.6	171-175
5	30	800	5.6	141-145
5	30	1600	5.6	146-150
5	30	400	2.8	151-155
5	15	1600	5.6	156-160

No scintillator sheet
Collimator Size (mm)	Exposure (s)	ISO	f-number	File no.	Comments	Image
60	10	400	5.6	69-73
50	10	400	5.6	74-78
40	13	400	5.6	79-83
35	15	400	5.6	84-88
30	15	400	5.6	89-93
25	20	400	5.6	94-98
20	25	400	5.6	99,101-104
15	30	400	5.6	106-110
12.5	30	400	5.6	111-115
10	30	400	5.6	116-120
7.5	30	400	5.6	121-130
5	30	400	5.6	131-140
60	4	400	5.6	195-199
60	6	400	5.6	200-204

Green scintillator sheet
Collimator Size (mm)	Exposure (s)	ISO	f-number	File no.	Comments	Image
60	2	400	5.6	281-285
60	3	400	5.6	286-290
60	4	400	5.6	291-295
60	6	400	5.6	296-300
60	10	400	5.6	301-305
50	10	400	5.6	306-310
50	2	400	5.6	311-315
40	13	400	5.6	316-320
40	2	400	5.6	321-325
35	4	400	5.6	326-330
35	15	400	5.6	331-335
30	15	400	5.6	336-340
30	4	400	5.6	341-345
25	20	400	5.6	346-350
25	5	400	5.6	351-355
20	25	400	5.6	356-360
20	6	400	5.6	361-365
15	30	400	5.6	366-370
12.5	30	400	5.6	377-381
10	30	400	5.6	382-386
7.5	30	400	5.6	387-391
5	30	400	5.6	392-396

Background
Collimator Size (mm)	Exposure (s)	ISO	f-number	File no.	Comments	Image
None	4	400	5.6	176
None	5	400	5.6	177
None	6	400	5.6	178
None	8	400	5.6	179
None	10	400	5.6	180
None	13	400	5.6	181
None	15	400	5.6	182
None	20	400	5.6	183
None	25	400	5.6	184
None	30	400	5.6	185