Multichannel detectors for profile measurements in clinical proton fields

Journal Article · Sun Jul 15 04:00:00 EDT 2007 · Medical Physics

DOI:https://doi.org/10.1118/1.2746513· OSTI ID:20953318

Nichiporov, Dmitri; Solberg, Keith; Wen, Hsi; Wolanski, Mark; Mascia, Anthony; Farr, Jonathan; Schreuder, Andries ^[1]

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1. Indiana University Cyclotron Facility, 2401 Milo B. Sampson Lane, Bloomington, Indiana 47408 (United States)

Two beam profile measurement detectors have been developed at Indiana University Cyclotron Facility to address the need for a tool to efficiently verify dose distributions created with active methods of clinical proton beam delivery. The multipad ionization chamber (MPIC) has 128 ionization chambers arranged in one plane and is designed to measure lateral profiles in fields up to 38 cm in diameter. The MPIC pads have a 5 mm pitch for fields up to 20 cm in diameter and a 7 mm pitch for larger fields, providing the accuracy of field size determination about 0.5 mm. The multilayer ionization chamber (MLIC) detector contains 122 small-volume ionization chambers stacked at a 1.82 mm step (water-equivalent) for depth-dose profile measurements. The MLIC detector can measure profiles up to 20 cm in depth, and determine the 80% distal dose fall-off with about 0.1 mm precision. Both detectors can be connected to the same set of electronics modules, which comprise the detectors' data acquisition system. The detectors have been tested in clinical proton fields produced with active methods of beam delivery such as uniform scanning and energy stacking. This article describes detector performance tests and discusses their results. The test results indicate that the MPIC and MLIC detectors can be used for dosimetric characterization of clinical proton fields. The detectors offer significant time savings during measurements in actively delivered beams compared with traditional measurements using a water phantom.

• OSTI ID: 20953318
• Journal Information: Medical Physics, Journal Name: Medical Physics Journal Issue: 7 Vol. 34; ISSN 0094-2405; ISSN MPHYA6
• Country of Publication: United States
• Language: English

Related Subjects

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
62 RADIOLOGY AND NUCLEAR MEDICINE
ACCURACY
BEAM PROFILES
DATA ACQUISITION SYSTEMS
DEPTH DOSE DISTRIBUTIONS
DOSIMETRY
IONIZATION CHAMBERS
IU CYCLOTRON
PHANTOMS
PROTON BEAMS
RADIATION DOSES
RADIOTHERAPY