The Radiation Boom — When the Beam-Shaper Was Left Out

The New York Times' 2010 investigation 'The Radiation Boom' documented modern linear-accelerator overdoses in New York hospitals. In one case a computer error during multileaf-collimator programming left the beam misshaped and directed errant radiation over three consecutive days; in another, a linac delivered repeated overdoses because a beam-modulating filter was missing. The consoles did not make the errors obvious to the operators.

These cases showed the Therac-25 lesson had not been fully learned: complex linac software, interrupted mid-programming or misconfigured, can deliver massive dose while the interface looks routine. The Times found beam-shaping devices were left out or misused on 133 occasions in New York alone. (Walt Bogdanich, 'Radiation Offers New Cures, and Ways to Do Harm,' The New York Times, 2010.)

1. A treatment plan is programmed on a modern linac using multileaf-collimator beam shaping.
2. The planning software crashes or is interrupted mid-programming, or a beam-modulating filter is left out.
3. The machine delivers a plan that was never correctly completed.
4. The console shows a routine treatment; the error is not obvious to the operator.
5. The overdose is repeated across successive sessions before it is caught.

Investigative record, not a frequency: 133 New York cases where beam-modifying devices were left out or misused. (NYT, 2010)

Repeated radiation far above plan. Shown through the linac gantry, the treatment console, and the empty vault — never the patient.