Table 2.

Pros and cons of selected materials for the IMRT compensator application

Material	Pro	Con
Cerrobend (with and without mold)	• readily available • inexpensive • recyclable • high density	• need a milling machine
brass/steel/lead (cube or sheet)	• no milling required • recyclable • inexpensive	• poor IM resolution due to discreteness • can be labor‐intensive for assembly. • can be hazardous (lead)
Lucite (solid)	• easy to machine • nonhazardous	• low density thus low IM magnitude • need a milling machine • not recyclable thus can be expensive
brass/steel (solid)	• readily available • can produce smooth IM • nonhazardous	• not recyclable thus can be expensive • need a milling machine
tin granule‐wax (mixture in mold)	• recyclable • can produce smooth IM • nonhazardous	• low density thus low IM magnitude • need a milling machine • difficult to keep consistent packing density
tin/steel (granule in mold)	• high IM resolution • consistent packing • nonhazardous • recyclable	• medium density ‐medium IM magnitude • need a milling machine
tungsten (powder in mold)	• high IM resolution • consistent packing • high density • recyclable	• slightly hazardous to handle in coarse powder form (less than Cerrobend and lead) • need a milling machine