Patient specific quality control for Stereotactic Ablative Body Radiotherapy (SABR): it takes more than one phantom

Kron, Tomas; Ungureanu, E; Antony, Rachitha; Hardcastle, Nicholas; Clements, Natalie; Ukath, J; Fox, C.; Lonski, Peta; Wanigaratne, D; Haworth, Annette

doi:10.1088/1742-6596/777/1/012017

Cited by 8 publications

(6 citation statements)

References 17 publications

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“… Abbreviations: AM, additive manufacturing; DMD, digital micromirror device; FDM, Fused Deposition Modelling; LENS, laser engineering net shape; LOM, laminated object material; PJT, polymer jetting technology; SLA, stereolithography; SLS, selective laser sintering; 3D, three-dimensional printing. a The heterogeneity found in the human body is becoming more important as more sophisticated radiotherapy techniques are employed such as stereotactic radiotherapy. 89 Therefore, simulating patient-specific tissue contrast requires the utilization of available standard AM printing parameters and AM polymers to manufacture clinically usefull imaging and dosimetry phantoms. …”

Section: Discussionmentioning

confidence: 99%

“… a The heterogeneity found in the human body is becoming more important as more sophisticated radiotherapy techniques are employed such as stereotactic radiotherapy. 89 Therefore, simulating patient-specific tissue contrast requires the utilization of available standard AM printing parameters and AM polymers to manufacture clinically usefull imaging and dosimetry phantoms. …”

Section: Discussionmentioning

confidence: 99%

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A Systematic Review on 3D-Printed Imaging and Dosimetry Phantoms in Radiation Therapy

Tino

Yeo

Leary

et al. 2019

Technol Cancer Res Treat

112

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Introduction: Additive manufacturing or 3-dimensional printing has become a widespread technology with many applications in medicine. We have conducted a systematic review of its application in radiation oncology with a particular emphasis on the creation of phantoms for image quality assessment and radiation dosimetry. Traditionally used phantoms for quality assurance in radiotherapy are often constraint by simplified geometry and homogenous nature to perform imaging analysis or pretreatment dosimetric verification. Such phantoms are limited due to their ability in only representing the average human body, not only in proportion and radiation properties but also do not accommodate pathological features. These limiting factors restrict the patient-specific quality assurance process to verify image-guided positioning accuracy and/or dose accuracy in “water-like” condition. Methods and Results: English speaking manuscripts published since 2008 were searched in 5 databases (Google Scholar, Scopus, PubMed, IEEE Xplore, and Web of Science). A significant increase in publications over the 10 years was observed with imaging and dosimetry phantoms about the same total number (52 vs 50). Key features of additive manufacturing are the customization with creation of realistic pathology as well as the ability to vary density and as such contrast. Commonly used printing materials, such as polylactic acid, acrylonitrile butadiene styrene, high-impact polystyrene and many more, are utilized to achieve a wide range of achievable X-ray attenuation values from −1000 HU to 500 HU and higher. Not surprisingly, multimaterial printing using the polymer jetting technology is emerging as an important printing process with its ability to create heterogeneous phantoms for dosimetry in radiotherapy. Conclusion: Given the flexibility and increasing availability and low cost of additive manufacturing, it can be expected that its applications for radiation medicine will continue to increase.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

A Systematic Review on 3D-Printed Imaging and Dosimetry Phantoms in Radiation Therapy

Tino

Yeo

Leary

et al. 2019

Technol Cancer Res Treat

112

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“…PSQA has proved challenging for stereotactic spine cases, even more so for those with surgical implants 12 . Surgical implants complicate the dosimetry further due to the presence of high‐density materials such as titanium 9 .…”

Section: Introductionmentioning

confidence: 99%

“…PSQA has proved challenging for stereotactic spine cases, even more so for those with surgical implants. 12 Surgical implants complicate the dosimetry further due to the presence of high-density materials such as titanium. 9 More recently carbon fiber-based implants have become available with the aim of improving radiotherapy treatment accuracy.…”

Section: Introductionmentioning

confidence: 99%

Investigation of the effects of spinal surgical implants on radiotherapy dosimetry: A study of 3D printed phantoms

et al. 2021

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Purpose The use of three‐dimensional (3D) printing to develop custom phantoms for dosimetric studies in radiotherapy is increasing. The process allows production of phantoms designed to evaluated specific geometries, patients, or patient groups with a defining feature. The ability to print bone‐equivalent phantoms has, however, proved challenging. The purpose of this work was to 3D print a series of three similar spine phantoms containing no surgical implants, implants made of titanium, and implants made of carbon fiber, for future dosimetric and imaging studies. Phantoms were evaluated for (a) tissue and bone equivalence, (b) geometric accuracy compared to design, and (c) similarity to one another. Methods Sample blocks of PLA, HIPS, and StoneFil PLA‐concrete with different infill densities were printed to evaluate tissue and bone equivalence. The samples were used to develop CT to physical (PD) and effective relative electron density (REDeff) conversion curves and define the settings for printing the phantoms. CT scans of the printed phantoms were obtained to assess the geometry and densities achieved. Mean distance to agreement (MDA) and DICE coefficient (DSC) values were calculated between contours defining the different materials, obtained from design and like phantom modules. HU values were used to determine PD and REDeff and subsequently evaluate tissue and bone equivalence. Results Sample objects showed linear relationships between HU and both PD and REDeff for both PLA and StoneFil. The PD and REDeff of the objects calculated using clinical CT conversion curves were not accurate and custom conversion curves were required. PLA printed with 90% infill density was found to have a PD of 1.11 ± 0.03 g.cm−3 and REDeff of 1.04 ± 0.02 and selected for tissue‐ equivalent phantom elements. StoneFil printed with 100% infill density showed a PD of 1.35 ± 0.03 g.cm−3 and REDeff of 1.24 ± 0.04 and was selected for bone‐equivalent elements. Upon evaluation of the final phantoms, the PLA elements displayed PD in the range of 1.10 ± 0.03 g.cm−3–1.13 ± 0.03 g.cm−3 and REDeff in the range of 1.02 ± 0.03–1.06 ± 0.03. The StoneFil elements showed PD in the range of 1.43 ± 0.04 g.cm−3–1.46 ± 0.04 g.cm−3 and REDeff in the range of 1.31 ± 0.04–1.33 ± 0.04. The PLA phantom elements were shown to have MDA of ≤1.00 mm and DSC of ≥0.95 compared to design, and ≤0.48 mm and ≥0.91 compared like modules. The StoneFil elements displayed MDA values of ≤0.44 mm and DSC of ≥0.98 compared to design and ≤0.43 mm and ≥0.92 compared like modules. Conclusions Phantoms which were radiologically equivalent to tissue and bone were produced with a high level of similarity to design and even higher level of similarity of one another. When used in conjunction with the derived CT to PD or REDeff conversion curves they are suitable for evaluating the effects of spinal surgical implants of varying material of construction.

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“…En dicha técnica se administran dosis altas por fracción a lesiones pequeñas que, sumados al movimiento de la lesión y la heterogeneidad del medio, hacen que se requiera de una radioterapia moderna y avanzada, como en el caso de: la radioterapia de intensidad modulada (IMRT), la arcoterapia volumétrica de intensidad modulada (VMAT) y la radioterapia de imagen guiada (IGRT) (Teoh et al, 2011). Teniendo en cuenta lo anterior, es de esperar que el control de calidad de paciente específico (PSQA por sus siglas en inglés) sea riguroso y se considere esencial para garantizar la entrega del tratamiento (Kron et al, 2017).…”

Section: Introductionunclassified

Análisis dosimétrico de paciente específico considerando movimiento respiratorio en cáncer de pulmón

Díaz¹

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En la actualidad, los simuladores físicos usados en la mayoría de los centros de radioterapia en Colombia no consideran incertidumbres por cambio de medio y movimiento de los tumores en las medidas de control de calidad de paciente específico. Por el contrario, estos consideran realizar los controles en medios homogéneos y condiciones estáticas. Al no tener en cuenta dichas variables se genera un sesgo, específicamente en casos de alta heterogeneidad y movimiento causando un error dosimétrico que llega a ser sistemático. En este trabajo se presenta el análisis dosimétrico retrospectivo llevado a cabo en el proceso de control de calidad de paciente específico en casos de radiocirugía de pacientes con cáncer de pulmón tratados en los años (2017-2019) del Centro Javeriano de Oncología del Hospital Universitario San Ignacio (CJO-HUSI). En el mismo, se realizó una cuantificación de la diferencia dosimétrica a partir del cálculo y la medición de la dosis absorbida con dos sistemas de detección (cámara de ionización y película radiocrómica), se usó el inserto de cavidad (densidad homogénea) del simulador físico ArcCHECK (de ahora en adelante simulador Cavity-plug) para condiciones estáticas y el simulador físico CIRS 002FLC heterogéneo en condiciones estáticas-dinámicas. Para hacer medidas dinámicas con este último, se diseñó un sistema electromecánico que permitió simular el movimiento asociado a la respiración con las amplitudes y frecuencias relacionadas con el movimiento pulmonar de un paciente tipo para evaluar su efecto en la distribución de la dosis. Con esto se buscó establecer valores de tendencia en los tratamientos de radiocirugía de pulmón dado el análisis de las diferencias dosimétricas a un número representativo de pacientes, para evaluar el control de calidad de paciente específico en el CJO-HUSI. Como conclusión, el incorporar el movimiento en los SPQA y analizarlo con el sistema de detección película radiocrómica (PRC) hizo que se presente un aumento en la diferencia dosimétrica debido a los efectos físicos (heterogeneidad de la dosis y efecto interacción) y demás variables que deben ser consideradas (parámetros de planeación, protocolos, etc.). Además, se determinó que es necesario realizar correcciones en las mediciones con cámara de ionización y el simulador heterogéneo debido a la determinación de dosis absoluta en medios de baja densidad. Por último, la PRC permitió obtener mayor información de la dosis depositada en una región de interés, sin embargo, es necesario considerar la realización de un proceso cuantificado (en el CJO-HUSI) que permita complementar la información obtenida en este trabajo. El uso del simulador heterogéneo dinámico responde a una recomendación internacional y permite evaluar los SPQA en condiciones más reales de tratamiento.

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Patient specific quality control for Stereotactic Ablative Body Radiotherapy (SABR): it takes more than one phantom

Cited by 8 publications

References 17 publications

A Systematic Review on 3D-Printed Imaging and Dosimetry Phantoms in Radiation Therapy

A Systematic Review on 3D-Printed Imaging and Dosimetry Phantoms in Radiation Therapy

Investigation of the effects of spinal surgical implants on radiotherapy dosimetry: A study of 3D printed phantoms

Análisis dosimétrico de paciente específico considerando movimiento respiratorio en cáncer de pulmón

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