The advantage of gel is 3D dosimetry. Why do you want to process a 3D dosimeter into 2D? For 2D, film dosimeters are commercially available, e.g., https://www.fujifilm.com/us/en/business/specialty-chemicals/cta-dosimeter-film. You need a reason why existing film dosimeters cannot work.

Thanks Dr: Kengo Shibuya for your answer , I want to do a study to compare between films and gel dosimetry and iwant to know are its applicable or not ??

(1) Difference between 3D and 2D

It should be considered based on the interactions between the radiation and material.

• Beta rays: the backscattering is negligible in 2D, but not in 3D.
• Gamma rays: the buildup effects need not be taken into account in 2D, but should be taken into account in 3D. Note that with low atomic numbers, Compton scattering is dominant and there is the little photoelectric effect.
• Heavy particles: the Bragg's Peak always appears in 3D; in 2D, it may not appear with a sufficiently thin film.

(2) 3D gels in 2D.

If the gel is hard enough, slice it with a razor blade. If it cannot stand on its own, hold it on another film etc.