Benchmarking beam alignment for a clinical helical tomotherapy device

• Published in: Medical physics (Lancaster) 2003-06, Vol.30 (6), p.1118-1127
• Main Authors: Balog, John, Mackie, T. R., Pearson, D., Hui, Susanta, Paliwal, Bhudatt, Jeraj, Robert
• Format: Article
• Language: English
• Subjects: Accelerators; beam alignment; Benchmarking - methods; Benchmarking - standards; Calibration - standards; Cancer; Collimation; collimators; commissioning dosimetry; Computed radiography; computerised tomography; dosimetry; Dosimetry/exposure assessment; Equipment Failure Analysis; Film Dosimetry - instrumentation; Film Dosimetry - methods; Film Dosimetry - standards; Gas‐filled counters: ionization chambers, proportional, and avalanche counters; Humans; ionisation chambers; linear accelerators; multileaf collimator; Physicists; Quality Control; Radiation detectors; radiation therapy; Radiometry - instrumentation; Radiometry - methods; Radiometry - standards; Radiotherapy Dosage; Radiotherapy, Computer-Assisted - methods; Radiotherapy, Computer-Assisted - standards; Radiotherapy, Conformal - instrumentation; Radiotherapy, Conformal - standards; Reproducibility of Results; Sensitivity and Specificity; Tomography, Spiral Computed - methods; Tomography, Spiral Computed - standards; tomotherapy; Wedges and compensators; X‐ and γ‐ray sources, mirrors, gratings, and detectors; X‐ray detection; X‐ray optics
• ISSN: 0094-2405; 2473-4209
• DOI: 10.1118/1.1576395

A clinical helical tomotherapy treatment machine has been installed at the University of Wisconsin Comprehensive Cancer Center. Beam alignment has been finalized and accepted by UW staff. Helical tomotherapy will soon be clinically available to other sites. Clinical physicists who expect to work with this machine will need to be familiar with its unique dosimetric characteristics, and those related to the geometrical beam configuration and its verification are described here. A series of alignment tests and the results are presented. Helical tomotherapy utilizes an array of post-patient xenon-filled megavoltage radiation detectors. These detectors have proved capable of performing some alignment verification tests. That is particularly advantageous because those tests can then be automated and easily performed on an ongoing basis.