Development of a PTV margin for preclinical irradiation of orthotopic pancreatic tumors derived from a well-known recipe for humans

In human radiotherapy a safety margin (PTV margin) is essential for successful irradiation and is usually part of clinical treatment planning. In preclinical radiotherapy research with small animals, most uncertainties and inaccuracies are present as well, but according to the literature a margin is...

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Main Authors: Severin Kampfer, Sophie Dobiasch, Stephanie E. Combs, Jan J. Wilkens
Format: Article
Language:English
Published: Elsevier 2024-11-01
Series:Zeitschrift für Medizinische Physik
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Online Access:http://www.sciencedirect.com/science/article/pii/S0939388923000429
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author Severin Kampfer
Sophie Dobiasch
Stephanie E. Combs
Jan J. Wilkens
author_facet Severin Kampfer
Sophie Dobiasch
Stephanie E. Combs
Jan J. Wilkens
author_sort Severin Kampfer
collection DOAJ
description In human radiotherapy a safety margin (PTV margin) is essential for successful irradiation and is usually part of clinical treatment planning. In preclinical radiotherapy research with small animals, most uncertainties and inaccuracies are present as well, but according to the literature a margin is used only scarcely. In addition, there is only little experience about the appropriate size of the margin, which should carefully be investigated and considered, since sparing of organs at risk or normal tissue is affected.Here we estimate the needed margin for preclinical irradiation by adapting a well-known human margin recipe from van Herck et al. to the dimensions and requirements of the specimen on a small animal radiation research platform (SARRP). We adjusted the factors of the described formula to the specific challenges in an orthotopic pancreatic tumor mouse model to establish an appropriate margin concept. The SARRP was used with its image-guidance irradiation possibility for arc irradiation with a field size of 10 × 10 mm2 for 5 fractions. Our goal was to irradiate the clinical target volume (CTV) of at least 90% of our mice with at least 95% of the prescribed dose. By carefully analyzing all relevant factors we gain a CTV to planning target volume (PTV) margin of 1.5 mm for our preclinical setup.The stated safety margin is strongly dependent on the exact setting of the experiment and has to be adjusted for other experimental settings. The few stated values in literature correspond well to our result. Even if using margins in the preclinical setting might be an additional challenge, we think it is crucial to use them to produce reliable results and improve the efficacy of radiotherapy.
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spelling doaj-art-c849e9cd23ad43ac95d73e6a3d3e645d2024-11-20T05:06:27ZengElsevierZeitschrift für Medizinische Physik0939-38892024-11-01344533541Development of a PTV margin for preclinical irradiation of orthotopic pancreatic tumors derived from a well-known recipe for humansSeverin Kampfer0Sophie Dobiasch1Stephanie E. Combs2Jan J. Wilkens3Department of Radiation Oncology, School of Medicine and Klinikum rechts der Isar, Technical University of Munich (TUM), Munich, Germany; Physics Department, Technical University of Munich (TUM), Garching, Germany; Corresponding author: Severin Kampfer, Klinikum rechts der Isar, Klinik und Poliklinik für RadioOnkologie und Strahlentherapie, Ismaninger Straße 22, 81675 München, Germany.Department of Radiation Oncology, School of Medicine and Klinikum rechts der Isar, Technical University of Munich (TUM), Munich, Germany; Institute of Radiation Medicine (IRM), Department of Radiation Sciences (DRS), Helmholtz Zentrum München, Neuherberg, GermanyDepartment of Radiation Oncology, School of Medicine and Klinikum rechts der Isar, Technical University of Munich (TUM), Munich, Germany; Institute of Radiation Medicine (IRM), Department of Radiation Sciences (DRS), Helmholtz Zentrum München, Neuherberg, Germany; German Cancer Consortium (DKTK), Partner Site Munich, GermanyDepartment of Radiation Oncology, School of Medicine and Klinikum rechts der Isar, Technical University of Munich (TUM), Munich, Germany; Physics Department, Technical University of Munich (TUM), Garching, Germany; Institute of Radiation Medicine (IRM), Department of Radiation Sciences (DRS), Helmholtz Zentrum München, Neuherberg, GermanyIn human radiotherapy a safety margin (PTV margin) is essential for successful irradiation and is usually part of clinical treatment planning. In preclinical radiotherapy research with small animals, most uncertainties and inaccuracies are present as well, but according to the literature a margin is used only scarcely. In addition, there is only little experience about the appropriate size of the margin, which should carefully be investigated and considered, since sparing of organs at risk or normal tissue is affected.Here we estimate the needed margin for preclinical irradiation by adapting a well-known human margin recipe from van Herck et al. to the dimensions and requirements of the specimen on a small animal radiation research platform (SARRP). We adjusted the factors of the described formula to the specific challenges in an orthotopic pancreatic tumor mouse model to establish an appropriate margin concept. The SARRP was used with its image-guidance irradiation possibility for arc irradiation with a field size of 10 × 10 mm2 for 5 fractions. Our goal was to irradiate the clinical target volume (CTV) of at least 90% of our mice with at least 95% of the prescribed dose. By carefully analyzing all relevant factors we gain a CTV to planning target volume (PTV) margin of 1.5 mm for our preclinical setup.The stated safety margin is strongly dependent on the exact setting of the experiment and has to be adjusted for other experimental settings. The few stated values in literature correspond well to our result. Even if using margins in the preclinical setting might be an additional challenge, we think it is crucial to use them to produce reliable results and improve the efficacy of radiotherapy.http://www.sciencedirect.com/science/article/pii/S0939388923000429CTV to PTV marginImage-guided high-precision radiationPancreatic cancerPreclinical tumor mouse modelSmall-animal radiation research platformTranslational research
spellingShingle Severin Kampfer
Sophie Dobiasch
Stephanie E. Combs
Jan J. Wilkens
Development of a PTV margin for preclinical irradiation of orthotopic pancreatic tumors derived from a well-known recipe for humans
Zeitschrift für Medizinische Physik
CTV to PTV margin
Image-guided high-precision radiation
Pancreatic cancer
Preclinical tumor mouse model
Small-animal radiation research platform
Translational research
title Development of a PTV margin for preclinical irradiation of orthotopic pancreatic tumors derived from a well-known recipe for humans
title_full Development of a PTV margin for preclinical irradiation of orthotopic pancreatic tumors derived from a well-known recipe for humans
title_fullStr Development of a PTV margin for preclinical irradiation of orthotopic pancreatic tumors derived from a well-known recipe for humans
title_full_unstemmed Development of a PTV margin for preclinical irradiation of orthotopic pancreatic tumors derived from a well-known recipe for humans
title_short Development of a PTV margin for preclinical irradiation of orthotopic pancreatic tumors derived from a well-known recipe for humans
title_sort development of a ptv margin for preclinical irradiation of orthotopic pancreatic tumors derived from a well known recipe for humans
topic CTV to PTV margin
Image-guided high-precision radiation
Pancreatic cancer
Preclinical tumor mouse model
Small-animal radiation research platform
Translational research
url http://www.sciencedirect.com/science/article/pii/S0939388923000429
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