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3D dosimeters
Advantages
•
Dosimeter is the phantom
(negligible to small p
phant
depending on type)
•
3D character
facilitates
concurrent measurements and
processing for minimizing
positional
and type A
uncertainty
•
negligible to small
f
rel
(depending on type)
•
No dose rate dependence
(except for methacrylic acid
based gels-MAGIC & PRESAGE
at very low dose rates)
Figure from: Rogers & Cygler (Eds), Clinical dosimetry measurements in radiotherapy (2009 AAPM Summer
School), Monograph No. 34, Medical Physics Publishing 2011
Disadvantages
•
Sensitivity varies with type and batch
•
k
rel
bq
can be significant for some dosimeters @
low E
•
3D character augments influences and problems
similar to that of films increasing type B
uncertainty