Systems, devices, and methods for delivering therapeutic particles are disclosed. In one variation, a device for delivering particles includes a gas supply configured for supplying gas under pressure, a particle cassette comprising the particles, a cassette housing, and a cassette membrane. The cassette housing can comprise an Ethylene Vinyl Acetate (EVA) copolymer of 18% to 28% by weight of Vinyl Acetate (VA). The device can also include a safety interlock to prevent or minimize the risk that the device will be unintentionally activated. The device can also have a silencer.
