Physical measurements with a high-energy proton beam using liquid and solid tissue substitutes

Constantinou, Christodoulos; Kember, N. F.; Huxable, G; Whitehead, Camilla Dunham; Stedeford, J. B. H.; Weatherburn, H.

doi:10.1088/0031-9155/25/3/008

Cited by 4 publications

(2 citation statements)

References 6 publications

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“…In no case did the readings at the depth differ by > 1% in each comparison. Similar tests were made with a 160 MeV synchrocyclotron proton beam and a neutron beam with average energy of 7.5 MeV (14,46). The results with the substitutes in place were generally within 0.5% of the readings for real tissues.…”

Section: Phantom Materials In Radiologysupporting

confidence: 58%

Phantom Materials in Radiology

Watanabe

Constantinou

2006

Encyclopedia of Medical Devices and Instrumentation

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In radiology, phantoms are utilized to estimate radiation dose delivered to patients and evaluate the quality of imaging systems. Hence, the material of the phantoms should closely mimic the human tissue; in particular, the radiological characteristics of the material must be similar to that of the tissue. This article reviews materials used to manufacture phantoms for radiology applications. In the first section, basic physics relevant to the phantom material and radiation interaction with matter is discussed. A brief history of the phantom material for radiology is offered. The second section gives extensive discussion on the materials mainly developed by D.R.White, C.Constantinou, and co‐workers in late 1970s to early 1980s. Their materials were made based on epoxy resin. They produced tissue‐equivalent materials mimicking 15 different tissue types. Detailed description on manufacturing methods and the results of evaluation is presented. Since their seminal work other investigators developed tissue‐equivalent materials by using polyethylene and polyurethane as base. Short discussion on those newer developments is given. The third section presents, how those materials are used for radiation dosimetry, radiation therapy, and diagnostic radiology. Our discussion on applications will be limited to the phantoms used with photons and electrons since most medical applications utilize those particles. The last section is devoted to speculative discussion on what types of phantom and material will be developed in the near future.

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Section: Phantom Materials In Radiologysupporting

confidence: 58%

Phantom Materials in Radiology

Watanabe

Constantinou

2006

Encyclopedia of Medical Devices and Instrumentation

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“…Dominiak developed a rectangular spine phantom to evaluate the craniospinal electron irradiation technique that was used by The University of Texas M. D. Anderson Cancer Center at that time (3) . To construct the phantom, human vertebral bodies were suspended in a container and tissue substitute material identified as “muscle substitute, solid rigid number 4” (MS/SR4) (4,5) was poured in around them. The MS/SR4 gradually hardened, resulting in a solid phantom with human vertebral bodies (T9 through L4) embedded within.…”

Section: Methodsmentioning

confidence: 99%

An anthropomorphic spine phantom for proton beam approval in NCI‐funded trials

Cho

Summers

2014

J Applied Clin Med Phys

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As part of the approval process for the use of scattered or uniform scanning proton therapy in National Cancer Institute (NCI)‐sponsored clinical trials, the Radiological Physics Center (RPC) mandates irradiation of two RPC anthropomorphic proton phantoms (prostate and spine). The RPC evaluates these irradiations to ensure that they agree with the institutions' treatment plans within criteria of the NCI‐funded cooperative study groups. The purpose of this study was to evaluate the use of an anthropomorphic spine phantom for proton matched‐field irradiation, and to assess its use as a credentialing tool for proton therapy beams. We used an anthropomorphic spine phantom made of human vertebral bodies embedded in a tissue substitute material called Muscle Substitute/Solid Rigid Number 4 (MS/SR4) comprising three sections: a posterior section containing the posterior surface and the spinous processes, and left and right (L/R) sections containing the vertebral bodies and the transverse processes. After feasibility studies at three institutions, the phantom, containing two thermoluminescent dosimeters (TLDs) for absolute dose measurements and two sheets of radiochromic film for relative dosimetry, was shipped consecutively to eight proton therapy centers participating in the approval study. At each center, the phantom was placed in a supine or prone position (according to the institution's spine treatment protocol) and imaged with computed tomography (CT). The images then were used with the institution's treatment planning system (TPS) to generate two matched fields, and the phantom was irradiated accordingly. The irradiated phantom was shipped to the RPC for analysis, and the measured values were compared with the institution's TPS dose and profiles using criteria of ± 7% for dose agreement and 5 mm for profile distance to agreement. All proton centers passed the dose criterion with a mean agreement of 3% (maximum observed agreement, 7%). One center failed the profile distance‐to‐agreement criterion on its initial irradiation, but its second irradiation passed the criterion. Another center failed the profile distance‐to‐agreement criterion, but no repeat irradiation was performed. Thus, seven of the eight institutions passed the film profile distance‐to‐agreement criterion with a mean agreement of 1.2 mm (maximum observed agreement 5 mm). We conclude that an anthropomorphic spine phantom using TLD and radiochromic film adequately verified dose delivery and field placement for matched‐field treatments.PACS number: 87.55.‐x, 87.55.N‐

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