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Improved MAGIC gel for higher sensitivity and elemental tissue equivalent 3D dosimetry
Author(s) -
Zhu Xuping,
Reese Timothy G.,
Crowley Elizabeth M.,
El Fakhri Georges
Publication year - 2010
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.3260844
Subject(s) - dosimetry , dosimeter , imaging phantom , materials science , elemental analysis , analytical chemistry (journal) , nuclear medicine , radiochemistry , chemistry , chromatography , medicine , organic chemistry
Purpose Polymer‐based gel dosimeter (MAGIC type) is a preferable phantom material for PET range verification of proton beam therapy. However, improvement in elemental tissue equivalency (specifically O/C ratio) is very desirable to ensure realistic time‐activity measurements. Methods Glucose and urea was added to the original MAGIC formulation to adjust the O/C ratio. The dose responses of the new formulations were tested with MRI transverse relaxation rate (R2) measurements. Results The new ingredients improved not only the elemental composition but also the sensitivity of the MAGIC gel. The O/C ratios of our new gels agree with that of soft tissue within 1%. The slopes of dose response curves were 1.6–2.7 times larger with glucose. The melting point also increased by 5 ° C . Further addition of urea resulted in a similar slope but with an increased intercept and a decreased melting point. Conclusions Our improved MAGIC gel formulations have higher sensitivity and better elemental tissue equivalency for 3D dosimetry applications involving nuclear reactions.