Physical Phantoms for Experimental Radiation Dosimetry

Hintenlang, David E.; Moloney, W; Winslow, J

doi:10.1201/ebk1420059793-c16

Cited by 3 publications

(3 citation statements)

References 32 publications

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“…Commercial anthropomorphic phantoms such as the RANDO (The Phantom Laboratory Inc, Salem, NY) and ATOM Dosimetry Verification Phantoms (CIRS Inc, Norfolk, VA) have been used for decades to study the performance of imaging systems and to assess the radiation dose received by patients undergoing medical procedures 1 . These phantoms have human‐like geometry and are composed of materials designed to mimic the photon attenuation and scattering properties of tissue.…”

Section: Introductionmentioning

confidence: 99%

Fabrication of a pediatric torso phantom with multiple tissues represented using a dual nozzle thermoplastic 3D printer

Mille

Griffin

Maass‐Moreno

et al. 2020

J Applied Clin Med Phys

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Purpose: To demonstrate an on-demand and nearly automatic method for fabricating tissue-equivalent physical anthropomorphic phantoms for imaging and dosimetry applications using a dual nozzle thermoplastic three-dimensional (3D) printer and two types of plastic. Methods: Two 3D printing plastics were investigated: (a) Normal polylactic acid (PLA) as a soft tissue simulant and (b) Iron PLA (PLA-Fe), a composite of PLA and iron powder, as a bone simulant. The plastics and geometry of a 1-yr-old computational phantom were combined with a dual extrusion 3D printer to fabricate an anthropomorphic imaging phantom. The volumetric fill density of the 3D-printed parts was varied to approximate tissues of different radiographic density using a calibration curve relating the printer infill density setting to measured CT number. As a demonstration of our method we printed a 10 cm axial cross-section of the computational phantom's torso at full scale. We imaged the phantom on a CT scanner and compared HU values to those of a 1-yr-old patient and a commercial 5-yr-old physical phantom. Results: The phantom was printed in six parts over the course of a week. The printed phantom included 30 separate anatomical regions including soft tissue remainder, lungs (left and right), heart, esophagus, rib cage (left and right ribs 1 to 10), clavicles (left and right), scapulae (left and right), thoracic vertebrae (one solid object defining thoracic vertebrae T1 to T9). CT scanning of the phantom showed five distinct radiographic regions (heart, lung, soft tissue remainder, bone, and air cavity) despite using only two types of plastic. The 3D-printed phantom demonstrated excellent similarity to commercially available phantoms, although key limitations in the printer and printing materials leave opportunity for improvement. Conclusion: Patient-specific anthropomorphic phantoms can be 3D printed and assembled in sections for imaging and dosimetry applications. Such phantoms will be useful for dose verification purposes when commercial phantoms are unavailable for purchase in the specific anatomies of interest.

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Section: Introductionmentioning

confidence: 99%

Fabrication of a pediatric torso phantom with multiple tissues represented using a dual nozzle thermoplastic 3D printer

Mille

Griffin

Maass‐Moreno

et al. 2020

J Applied Clin Med Phys

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show abstract

“…Table 4 lists examples of several such phantoms by the CIRS and Kyoto Kagaku Co. that are used for image analysis. With anatomically realistic computational phantoms, the UF group led by David Hintenlang has fabricated several physical phantoms representing a newborn, 1-year old, and adult male (Hintenlang et al 2010). Rapid prototyping processes were also used to quickly produce physical phantoms from patient-specific data (Mille and Xu 2008).…”

Section: Physical Phantomsmentioning

confidence: 99%

An exponential growth of computational phantom research in radiation protection, imaging, and radiotherapy: a review of the fifty-year history

2014

Phys. Med. Biol.

225

227

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Radiation dose calculation using models of the human anatomy has been a subject of great interest to radiation protection, medical imaging, and radiotherapy. However, early pioneers of this field did not foresee the exponential growth of research activity as observed today. This review article walks the reader through the history of the research and development in this field of study which started some 50 years ago. This review identifies a clear progression of computational phantom complexity which can be denoted by three distinct generations. The first generation of stylized phantoms, representing a grouping of less than dozen models, was initially developed in the 1960s at Oak Ridge National Laboratory to calculate internal doses from nuclear medicine procedures. Despite their anatomical simplicity, these computational phantoms were the best tools available at the time for internal/external dosimetry, image evaluation, and treatment dose evaluations. A second generation of a large number of voxelized phantoms arose rapidly in the late 1980s as a result of the increased availability of tomographic medical imaging and computers. Surprisingly, the last decade saw the emergence of the third generation of phantoms which are based on advanced geometries called boundary representation (BREP) in the form of Non-Uniform Rational B-Splines (NURBS) or polygonal meshes. This new class of phantoms now consists of over 287 models including those used for non-ionizing radiation applications. This review article aims to provide the reader with a general understanding of how the field of computational phantoms came about and the technical challenges it faced at different times. This goal is achieved by defining basic geometry modeling techniques and by analyzing selected phantoms in terms of geometrical features and dosimetric problems to be solved. The rich historical information is summarized in four tables that are aided by highlights in the text on how some of the most well-known phantoms were developed and used in practice. Some of the information covered in this review has not been previously reported, for example, the CAM and CAF phantoms developed in 1970s for space radiation applications. The author also clarifies confusion about “population-average” prospective dosimetry needed for radiological protection under the current ICRP radiation protection system and “individualized” retrospective dosimetry often performed for medical physics studies. To illustrate the impact of computational phantoms, a section of this article is devoted to examples from the author’s own research group. Finally the author explains an unexpected finding during the course of preparing for this article that the phantoms from the past 50 years followed a pattern of exponential growth. The review ends on a brief discussion of future research needs (A supplementary file “3DPhantoms.pdf” to Figure 15 is available for download that will allow a reader to interactively visualize the phantoms in 3D).

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“…Seu objetivo foi avaliar testes de controle de qualidade e monitorar as doses a que o paciente é exposto em exames de TC (85) . Os materiais escolhidos para a construção de um simulador físico devem características equivalentes a tecidos humanos, como densidade e coeficiente de atenuação mais próxima possível dos tecidos simulados (86) . A calota craniana é constituída de duas camadas de osso cortical ou compacto, externa e interna, e entre elas uma camada de osso trabecular ou esponjoso, visto na Figura 24.…”

Section: Figura 22unclassified

Desenvolvimento e aplicação de um simulador pediátrico craniano para dosimetria em tomografia computadorizada

Martins¹

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To determine the exposure levels and the absorbed dose in patients undergoing CT scans, is necessary to calculate the CT dose index in measurements with a PMMA or water phantom. The phantom must be enough to simulate the attenuation and scattering characteristics of a human body or parts in a radiation field. The CT specific quantities : CT air kerma index (Ca,100) , weighted CT air kerma index (CW), a total volume CT air kerma index (Cvol) and the CT air kerma-lenght product (PKL) must be determined and compared to literature reference levels. In this work a head pediatric phantom was developed, considering that the Brazilian published Diagnostic Reference Levels (DRL) are based on adult phantom measurements. This developed phantom shows a construction innovation using materials to simulate the skullcap, cortical bone (aluminum) and cancellous bone (PVC), and it was filled with distilled water. The phantom dimension follows the recommendations of the World Health Organization and the International Commission on Radiation Units for children from 0 to 5 years old head size: diameter of 160 mm and height of 155 mm. The skullcap has 4 mm of thickness and 111.9 mm of internal diameter. In order to evaluate its behavior, tests were carried out in calibration laboratories and in clinical beams. The results showed attenuation up to 23% when different materials are used as skullcap, demonstrating that the DRL's adopted could be overestimating the dose received by pediatric patients. It is observed that the dose received by CT skull scans presents different distribution, due to the skullcap partially attenuation and/or backscattering which is not considered when the PMMA phantom is used.

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Physical Phantoms for Experimental Radiation Dosimetry

Cited by 3 publications

References 32 publications

Fabrication of a pediatric torso phantom with multiple tissues represented using a dual nozzle thermoplastic 3D printer

Fabrication of a pediatric torso phantom with multiple tissues represented using a dual nozzle thermoplastic 3D printer

An exponential growth of computational phantom research in radiation protection, imaging, and radiotherapy: a review of the fifty-year history

Desenvolvimento e aplicação de um simulador pediátrico craniano para dosimetria em tomografia computadorizada

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