Optical CT scanning of crosslinked radiochromic gel without cylinder wall

1
Optical CT scanning of cross-linked radiochromic
gel without cylinder wall Kevin Jordan DOSGEL
2008 Hersonissos, Crete, Greece
Schulich School of Medicine Dentistry
The University of Western Ontario
2
Introduction

• wall less scanning simplifies refractive index
  matching, should eliminate external reflections
  (cone beam CT DOSGEL06), wall polarization
  effects (optical activity, DOSGEL99, 04)
• thin teflon walls best match
• no wall even better
• problems chemical isolation, mechanical support

3
Micelle gels Chromophore diffusion size, shape,
charge, polarity, ion strength, pH, temperature,
gel type
Jordan
4

• Genipin gel
• genipin extract of gardenia fruit, Chinese
• medicine, (diabetes?),
• genipin crosslinks polymers to form
• non-toxic, blue gel
• Applications
• tissue engineering, tissue scaffolding,
• drug delivery, wound healing
• 2) gels for food (replacements for gelatin due
• to Mad Cow disease),
• 3) forensics (finger print detection, absorption
• and fluorescence),

Jordan
5
Genipin gel preparation
98 H20 2 gelatin 0.0002 genipin
H2SO4 0.2 M
5 20 hr
45 C
Jordan
6
Jordan
7
Jordan
8
Jordan
9
dmulaser dmuVista , correct ROFs stray light
effect small for bleaching gel!
Jordan
10
Genipin gel photobleaching response image stable
at 22C, in dark for gt 10 months!! Application
writing high resolution images in optical CT for
QA phantoms
Jordan
11
Vista10 transmission image
10 MV, 20 mm x 20 mm, 25 Gy
Jordan
12
Transverse slice from 3D reconstruction
Vista10 cone beam CT 512 projections voxel
dimension 0.5 mm x 0.5 mm x 0.5 mm
note lateral shift of gel between pre and post
scans
Jordan
13
Jordan
14
Conclusions genipin cross-linked gelatin gel new
class of radiochromic hydrogel zero diffusion 2
gelatin by mass gels are essentially a water
equivalent 3D dosimeter because there is no
diffusion for the active species and
cross-linking strengthens matrix, vessel wall
can be removed gel will not dissolve at room
temperature in liquid surface dosimetry is
possible using genipin gel
Jordan
15
Optical CT of complex geometry
Jordan
16
Optical CT of complex geometry
Jordan
17
Genipin gelatin finger phantom finger
OD(25,12.5,4.5 mm)
Jordan
18
Vista CBCT Genipin fingers Attenuation
coefficient cm-1 0.118 0.130 0.114
Jordan
19
(No Transcript)