Radiation dose computation algorithms employed in radiotherapy planning are developed after extensive research. However, as with every computerized algorithm, they need to undergo scrutiny and validation before clinical dose computation. As the algorithms are getting more and more complex, traditional approaches to validate them are no longer enough.
Commercial transport-based dose algorithm such as Acuros XB™ by Varian Medical Systems is typically validated by measurement in water equivalent (unit density) plastic phantoms. In order to evaluate dose computation in heterogeneous organs and tissues, commercial heterogeneous slabs and objects are available. The commercial heterogeneities are quite expensive.
By using 3D printing on Fused Deposition Modeling (FDM) printers, which are readily available on small budget (now around $500) we presented a cheap but quality alternative. This approach is equally valid if you are in small clinics in higher income or working in a low income country. After performing QA on the 3D printer, slab of variable density can be printed to a custom specification. The slabs can be scanned with a CT scanner, dose is computed, and plan is generated for the algorithm to be validated. The treatment plan is then delivered on radiochromic films embedded in between the 3D printed plastics. The radiation dose is measured from reading the films. The measured dose from the films can be compared to the computed dose under heterogeneous conditions and thus validated.
