A spiral phantom for IMRT and tomotherapy treatment delivery verification

Bhudatt Paliwal, Wolfgang Tomé, Susan Richardson, T. Rockwell Mackie

Research output: Contribution to journalArticlepeer-review

20 Scopus citations


A solid water/cylindrical phantom is machined to create a spiral cavity for placing radiographic or radiochromatic film in a spiral configuration. This spiral phantom is used to sample, predict, and measure data in three-dimension subspace. The predicted data are obtained by projecting the patient plan data on the spiral phantom in the treatment planning software. The measured data are obtained by irradiating the spiral phantom (with film in the spiral cavity) as per the treatment plan. The predicted and measured data are converted to a two-dimensional matrix and plotted as a spiralogram. Comparison of these predicted and measured spiralograms provides a quantitative comparison and thus validation of treatment delivered as planned. The spiral phantom is a simple, cost-effective approach to sample 3D data from complexly shaped, intensity modulated or compensated multiple beams. A software script is being written to automate the entire process of projection, data sampling, and comparison. Design aspects and some examples of dose verification are presented. The usefulness of the spiral phantom for intensity modulated radiation therapy and dynamic field shaping are discussed.

Original languageEnglish (US)
Pages (from-to)2503-2507
Number of pages5
JournalMedical physics
Issue number11
StatePublished - Jan 1 2000
Externally publishedYes


  • IMRT treatment plan verification
  • QA phantom

ASJC Scopus subject areas

  • Biophysics
  • Radiology Nuclear Medicine and imaging


Dive into the research topics of 'A spiral phantom for IMRT and tomotherapy treatment delivery verification'. Together they form a unique fingerprint.

Cite this