Abstract：
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 degrees 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.
journal_name
Med Physjournal_title
Medical physicsauthors
Zhu X,Reese TG,Crowley EM,El Fakhri Gdoi
10.1118/1.3260844subject
Has Abstractpub_date
2010-01-01 00:00:00pages
183-8issue
1eissn
0094-2405issn
2473-4209journal_volume
37pub_type
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