Abstract
Purpose: To evaluate a 2D ion chamber array detector as a quality assurance device for spot scanning proton beams at the Proton Therapy Center‐Houston (PTC‐H). Method and Materials The proton therapy machine at PTC‐H is equipped with a spot scanning delivery system in one of its gantry. The machine can deliver beams in energy range of 70–250 MeV corresponding to 4.08–37.94 cm depths in water, respectively. We have used a 2D ion chamber array detector to measure the depth dose curve and the dose profiles at different depths in a plastic water phantom for a single spot scanning proton beam with a nominal range in water of 10.5 cm. The 2D array device is equipped with 32 × 32 parallel plate ion chambers, each with 4.5 mm diameters and 7.5 cm center‐to‐center separation. The depth dose and profiles were compared with the ones measured using an ion chamber in the water. Results: The range of proton beam corresponding to the distal 90% depth dose was found to be within 1‐mm of that obtained from measurements using a Markus ion chamber measurement in water. The 2D lateral profile at depth of 10.39‐cm agreed well with the profile measured in a water phantom using a PinPoint ion chamber. A Gaussian fit of the profile data predicated one sigma parameter of 9.4‐mm at a depth in water of 10.39‐cm. Conclusion: The results indicate that the 2D in chamber array detector is a suitable device for quality assurance checks of spot scanning proton beams.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 2779 |
| Number of pages | 1 |
| Journal | Medical physics |
| Volume | 35 |
| Issue number | 6 |
| DOIs | |
| State | Published - Jun 2008 |
ASJC Scopus subject areas
- Biophysics
- Radiology Nuclear Medicine and imaging