Image Guided Radiation Therapy Strategies for Pelvic Lymph Node Irradiation in High-Risk Prostate Cancer: Motion and Margins
Autor: | Lucy E Kershaw, Floris J. Pos, Wilma D. Heemsbergen, Laila van Zadelhoff, Marcel van Herk |
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Přispěvatelé: | Other departments, CCA - Imaging and biomarkers |
Rok vydání: | 2017 |
Předmět: |
Male
Cancer Research medicine.medical_specialty medicine.medical_treatment Planning target volume 030218 nuclear medicine & medical imaging Pelvis 03 medical and health sciences Prostate cancer 0302 clinical medicine Prostate Medicine Humans Radiology Nuclear Medicine and imaging Organ Motion Lymph node Image-guided radiation therapy Radiation Lymphatic Irradiation business.industry Radiotherapy Planning Computer-Assisted Prostatic Neoplasms Seminal Vesicles medicine.disease Surgery Radiation therapy medicine.anatomical_structure Oncology 030220 oncology & carcinogenesis Tomography Lymph Nodes Anatomic Landmarks business Nuclear medicine Tomography X-Ray Computed Radiotherapy Image-Guided |
Zdroj: | International journal of radiation oncology, biology, physics, 100(1), 68-77. Elsevier Inc. |
ISSN: | 1879-355X 0360-3016 |
Popis: | Purpose To quantify the relative motion of the pelvic lymph nodes (LNs), seminal vesicles (SV) and prostate and define indicative margins for image-guided radiotherapy based on bony anatomy or prostate correction strategies for a 3 or 6 degrees-of-freedom couch. Methods and Materials Nineteen patients had a planning computed tomography (CT) scan followed by a mean of 11 repeated CT scans during radiation therapy. The prostate, SV, and external and internal iliac LN regions on the left and right were outlined on each CT scan. Systematic and random uncertainties were determined along with correlations between the motions of these regions. The clinical target volume to planning target volume margins required to take only motion into account were calculated for each guidance method. Results For bone guidance, motion of the prostate and LNs was largely uncorrelated. Margins to compensate for motion (left–right, superior–inferior, anterior–posterior, in cm) based on a 3-DOF couch were as follows: prostate (0.2, 0.6, 0.8), SV (0.4, 0.9, 1.0), and LNs (0.3, 0.4, 0.6). For prostate guidance, margins were calculated for correlated motion: prostate (0, 0, 0), SV (0.3, 0.5, 0.4), and LNs (0.3, 0.5, 0.9). For a 6-DOF couch, these margins were as follows: prostate (0.2, 0.6, 0.8), SV (0.3, 0.9, 1.0), and LNs (0.3, 0.4, 0.3) for bone guidance. For prostate guidance, margins were as follows: prostate (0, 0, 0), SV (0.2, 0.5, 0.4), and LNs (0.3, 0.6, 0.6). Conclusions Image guided radiation therapy based on bony anatomy requires larger prostate and SV margins, and guidance on prostate requires larger LN margins. Neither guidance strategy is optimal, and a combination of the 2 or treatment adaptation after a number of fractions might be preferable. Calculation of the total margin should also include delineation uncertainties. |
Databáze: | OpenAIRE |
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