Validation of a prototype optical computed tomography system

In radiation cancer treatments, the most of the side effects could be minimized using a proper dosimeter. Gel dosimeter is the only
three‑dimensional dosimeter and magnetic resonance imaging (MRI) is the gold standard method for gel dosimeter readout. Because
of hard accessibility and high cost of sample reading by MRI systems, some other alternative methods were developed. The optical
computed tomography (OCT) method could be considered as the most promising alternative method that has been studied widely.
In the current study, gel dosimeter scanning using a prototype optical scanner and validation of this optical scanner was performed.
Optical absorbance of the irradiated gel samples was determined by both of conventional spectrophotometer and the fabricated OCT
system at 632 nm. Furthermore, these irradiated vials were scanned by a 1.5 T MRI. The slope of the curves was extracted as the
dose‑response sensitivity. The R2‑dose sensitivity measured by MRI method was 0.1904 and 0.113 for NIPAM and PAGAT gels,
respectively. The optical dose sensitivity obtained by conventional spectrophotometer and the fabricated optical scanner was 0.0453
and 0.0442 for NIPAM gels and 0.0244 and 0.0242 for PAGAT gels, respectively. The scanning results of the absorbed dose values
showed that the new OCT and conventional spectrophotometer were in fair agreement. From the results, it could be concluded that
the fabricated system is able to quantize the absorbed dose values in polymer gel samples with acceptable accuracy