Design, development, and implementation of the Radiological Physics Center’s pelvis and thorax anthropomorphic quality assurance phantoms

• Published in: Medical physics (Lancaster) 2007-06, Vol.34 (6), p.2070-2076
• Main Authors: Followill, David S., Evans, DeeAnn Radford, Cherry, Christopher, Molineu, Andrea, Fisher, Gary, Hanson, William F., Ibbott, Geoffrey S.
• Format: Article
• Language: English
• Subjects: ACCURACY; ANATOMY; Ancillary equipment; Anthropometry - instrumentation; anthropomorphic phantoms; Biomimetic Materials; CHEST; CLINICAL TRIALS; COMMISSIONING; Computed tomography; DOSIMETRY; Dosimetry/exposure assessment; Equipment Design; Equipment Failure Analysis; Health Physics - instrumentation; Health Physics - methods; Humans; Intensity modulated radiation therapy; Lungs; Medical imaging; Medical treatment planning; Pelvic Neoplasms - diagnosis; Pelvic Neoplasms - radiotherapy; PELVIS; PHANTOMS; Phantoms, Imaging; QUALITY ASSURANCE; Quality assurance in radiotherapy; Quality Assurance, Health Care - methods; radiation therapy; Radiation treatment; RADIOLOGY AND NUCLEAR MEDICINE; Radiometry - instrumentation; Radiometry - methods; RADIOTHERAPY; Radiotherapy Dosage; Radiotherapy Planning, Computer-Assisted - instrumentation; Radiotherapy Planning, Computer-Assisted - methods; Record and verify systems and applications; Reproducibility of Results; Sensitivity and Specificity; Stereotactic radiosurgery; THERMOLUMINESCENT DOSEMETERS; thermoluminescent dosimeters; Thoracic Neoplasms - diagnosis; Thoracic Neoplasms - radiotherapy
• ISSN: 0094-2405; 2473-4209
• DOI: 10.1118/1.2737158

The Radiological Physics Center (RPC) developed two heterogeneous anthropomorphic quality assurance phantoms for use in verifying the accuracy of radiation delivery: one for intensity-modulated radiation therapy (IMRT) to the pelvis and the other for stereotactic body radiation therapy (SBRT) to the thorax. The purpose of this study was to describe the design and development of these two phantoms and to demonstrate the reproducibility of measurements generated with them. The phantoms were built to simulate actual patient anatomy. They are lightweight and water-fillable, and they contain imageable targets and organs at risk of radiation exposure that are of similar densities to their human counterparts. Dosimetry inserts accommodate radiochromic film for relative dosimetry and thermoluminesent dosimetry capsules for absolute dosimetry. As a part of the commissioning process, each phantom was imaged, treatment plans were developed, and radiation was delivered at least three times. Under these controlled irradiation conditions, the reproducibility of dose delivery to the target TLD in the pelvis and thorax phantoms was 3% and 0.5%, respectively. The reproducibility of radiation-field localization was less than 2.5 mm for both phantoms. Using these anthropomorphic phantoms, pelvic IMRT and thoracic SBRT radiation treatments can be verified with a high level of precision. These phantoms can be used to effectively credential institutions for participation in specific NCI-sponsored clinical trials