P13.21 PET-based dose painting radiation therapy strategy in a glioblastoma rat model using the small animal radiation research platform

2021 ◽  
Vol 23 (Supplement_2) ◽  
pp. ii37-ii37
Author(s):  
S Donche ◽  
J Verhoeven ◽  
C Bouckaert ◽  
B Descamps ◽  
R Raedt ◽  
...  
Keyword(s):  
Radiation Therapy ◽  
Treatment Planning ◽  
Rat Model ◽  
Planning Process ◽  
Radiation Treatment ◽  
Dose Delivery ◽  
Fet Pet ◽  
Irradiation System ◽  
Preclinical Treatment ◽  
Radiation Research

Abstract BACKGROUND Previously, a rat glioblastoma model to mimic chemo-radiation treatment of human glioblastoma in the clinic was established. Similarly to the clinic, CT and MRI were combined during the treatment planning process. PET imaging was subsequently added which allowed us to implement sub-volume boosting using a micro-irradiation system. However, combining three imaging modalities (CT, MRI and PET) using a micro-irradiation system, proved to be labour intensive because multimodal imaging, treatment planning and dose delivery have to be completed sequentially in the preclinical setting. MATERIAL AND METHODS Two different methodologies were compared in silico for performing preclinical [18F]FET PET based radiation therapy (20 Gy based on MRI, 8 Gy boost based on PET) based on three different cases. Method 1 is based on the previously published methods1,2. However, the process is automated using an in-house developed MATLAB code. Method 2 consists of a more sophisticated method where a series of isocenters and jaw dimensions for the motorised variable collimator were determined based on the [18F]FET PET uptake. Both methods were evaluated by means of the dose volume histograms (DVH) and Q-volume histograms. RESULTS The setup parameters for both methods were calculated. The DVHs for method 2 are systematically closer to the ideal dose distribution compared to method 1. These findings are confirmed by the D90 and D50 values which are considerably lower for method 1. When observing the Q-factor, method 2 always results in dose distributions that are closer to the dose objectives (method 1: 0.141±0.046; method 2: 0.064±0.011). CONCLUSION The described novel method to optimize the preclinical treatment planning process has many advantages in terms of dose delivery, time efficiency and variability, when compared to the previously used methods1,2. These improvements are important to narrow the gap between clinical and preclinical radiation research and for the development of new therapeutics and/or radiation therapy procedures for glioblastoma. 1. Bolcaen, J., Descamps, B., Boterberg, T., Vanhove, C. & Goethals, I. PET and MRI Guided Irradiation of a Glioblastoma Rat Model Using a Micro-irradiator. J. Vis. Exp. 1–10 (2017) doi:10.3791/56601. 2. Verhoeven, J. et al. Technical feasibility of [18F]FET and [18F]FAZA PET guided radiotherapy in a F98 glioblastoma rat model. Radiat. Oncol. 14, (2019).

Advances in Image-Guided Radiation Therapy

2007 ◽  
Vol 25 (8) ◽  
pp. 938-946 ◽  
Author(s):  
Laura A. Dawson ◽  
David A. Jaffray
Keyword(s):  
Radiation Therapy ◽  
Radiation Oncology ◽  
Planning Process ◽  
Radiation Treatment ◽  
Healthy Tissue ◽  
Tumor Control ◽  
Computer Assisted ◽  
Image Guided Radiation Therapy ◽  
Image Guided ◽  
Radiation Delivery

Imaging is central to radiation oncology practice, with advances in radiation oncology occurring in parallel to advances in imaging. Targets to be irradiated and normal tissues to be spared are delineated on computed tomography (CT) scans in the planning process. Computer-assisted design of the radiation dose distribution ensures that the objectives for target coverage and avoidance of healthy tissue are achieved. The radiation treatment units are now recognized as state-of-the-art robotics capable of three-dimensional soft tissue imaging immediately before, during, or after radiation delivery, improving the localization of the target at the time of radiation delivery, to ensure that radiation therapy is delivered as planned. Frequent imaging in the treatment room during a course of radiation therapy, with decisions made on the basis of imaging, is referred to as image-guided radiation therapy (IGRT). IGRT allows changes in tumor position, size, and shape to be measured during the course of therapy, with adjustments made to maximize the geometric accuracy and precision of radiation delivery, reducing the volume of healthy tissue irradiated and permitting dose escalation to the tumor. These geometric advantages increase the chance of tumor control, reduce the risk of toxicity after radiotherapy, and facilitate the development of shorter radiotherapy schedules. By reducing the variability in delivered doses across a population of patients, IGRT should also improve interpretation of future clinical trials.

scholarly journals Impact of Peer Review in the Radiation Treatment Planning Process: Experience of a Tertiary Care University Hospital in Pakistan

2019 ◽  
pp. 1-7
Author(s):  
Bilal Mazhar Qureshi ◽  
Muhammad Atif Mansha ◽  
Muneeb Uddin Karim ◽  
Asim Hafiz ◽  
Nasir Ali ◽  
...  
Keyword(s):  
Radiation Therapy ◽  
Peer Review ◽  
Clinical Target Volume ◽  
Planning Process ◽  
Radiation Treatment ◽  
Tertiary Care ◽  
Major Change ◽  
Target Volume ◽  
University Hospital ◽  
Treatment Plans

PURPOSE To evaluate and report the frequency of changes in radiation therapy treatment plans after peer review in a simulation review meeting once a week. MATERIALS AND METHODS Between July 1 and August 31, 2016, the radiation plans of 116 patients were discussed in departmental simulation review meetings. All plans were finalized by the primary radiation oncologist before presenting them in the meeting. A team of radiation oncologists reviewed each plan, and their suggestions were documented as no change, major change, minor change, or missing contour. Changes were further classified as changes in clinical target volume, treatment field, or dose. All recommendations were stratified on the basis of treatment intent, site, and technique. Data were analyzed by Statistical Package for the Social Sciences and are presented descriptively. RESULTS Out of 116 plans, 26 (22.4%) were recommended for changes. Minor changes were suggested in 15 treatment plans (12.9%) and a major change in 10 (8.6%), and only one plan was suggested for missing contour. The frequency of change recommendations was greater in radical radiation plans than in palliative plans (92.3% v 7.7%). The head and neck was the most common treatment site recommended for any changes (42.3%). Most of the changes were recommended in the technique planned with three-dimensional conformal radiation therapy (50%). Clinical target volume (73.1%) was identified as the most frequent parameter suggested for any change, followed by treatment field (19.2%) and dose (0.08%). CONCLUSION Peer review is an important tool that can be used to overcome deficiencies in radiation treatment plans, with a goal of improved and individualized patient care. Our study reports changes in up to a quarter of radiotherapy plans.

Sensitivity of plan re-optimizaton to errors in deformable image registration in online adaptive image-guided radiation therapy

2016 ◽  
Author(s):  
◽  
Brian Douglas McClain
Keyword(s):  
Radiation Therapy ◽  
Image Registration ◽  
Treatment Planning ◽  
Planning Process ◽  
Treatment Plan ◽  
Dose Calculation ◽  
Deformable Image Registration ◽  
University Of Missouri ◽  
Image Guided Radiation Therapy ◽  
Image Guided

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] Online adaptive image-guided radiation therapy has been a longstanding topic of interest in the field of radiation oncology due to its unique ability to tailor a dose distribution to account for inter-fractional variations and motion of critical structuresthrough daily online re-planning. Efforts are now being made to optimize steps of the adaptive process so that treatment planning and dose delivery can be practically administered while the patient is on the treatment couch. Automated image deformation and segmentation algorithms, along with fast dose calculation and plan re-optimization, have been implemented to streamline the online adaptive treatment planning process. Due to the complexity of inter-fractional anatomical deformations, obtaining precise delineation of target and structure volumes through deformable image registration (DIR) and auto-segmentation is a challenge. Mapping accurate organ at risk (OAR) contours through DIR and auto-segmentation is especially challenging for abdomen and pelvis treatment sites known to have significant interfractionaanatomical variations. While others have studied the accuracy of auto-deformed contours and potential errors and risk factors in the adaptive radiotherapy (ART) process, this study aims to determine if accounting for these errors within specific regions of interest (ROIs) can produce a comparable treatment plan without compromising PTV coverage, OAR sparing or overall plan quality. Once the correlation between dosimetric differences and geometric errors has been identified, a system will be developed to guide the physician in focusing their contour edits to the locations that matter most to the non-deterministic optimization algorithm.

SU-E-T-253: Treatment Planning and Dose Delivery of Photon Radiation Therapy of Cardiac Arrhythmias for Isolated Perfused Porcine Hearts

2013 ◽  
Vol 40 (6Part14) ◽  
pp. 262-262
Author(s):  
L Song ◽  
H Lehmann ◽  
J Cusma ◽  
J Misiri ◽  
K Parker ◽  
...  
Keyword(s):  
Radiation Therapy ◽  
Treatment Planning ◽  
Cardiac Arrhythmias ◽  
Photon Radiation ◽  
Dose Delivery

Dosimetric characterisation of anthropomorphic PRESAGE® dosimeter and EBT2 film for partial breast radiotherapy

2017 ◽  
Vol 17 (1) ◽  
pp. 96-103 ◽  
Author(s):  
Khalid Iqbal ◽  
Geoffrey S. Ibbott ◽  
Ryan Grant Lafratta ◽  
Kent A. Gifford ◽  
Saeed A. Buzdar
Keyword(s):  
Treatment Planning ◽  
Planning Process ◽  
Radiation Treatment ◽  
Tumour Volume ◽  
Planning System ◽  
Treatment Planning System ◽  
Partial Breast Irradiation ◽  
Dose Volume Histograms ◽  
Optical Computed Tomography ◽  
Ebt2 Film

AbstractPurposeWhole-breast external beam radiotherapy results in significant reduction in the risk for breast cancer-related death, but this may be offset by an increase in deaths from other causes and toxicity to surrounding organs. Partial breast irradiation techniques are approaches that treat only the lumpectomy area rather than the whole breast. Quality assurance in the radiation therapy treatment planning process is essential to ensure accurate dose delivery to the patient. For this purpose, this article compares the results from an anthropomorphic PRESAGE® dosimeter, radiation treatment planning system and from the GAFCHROMIC® EBT2 film.Materials and methodsA breast dosimeter was created and a three-field partial plan was generated in the Pinnacle3 treatment planning system. Dose distribution comparisons were made between Pinnacle3 treatment planning system, GAFCHROMIC® EBT2 film and PRESAGE® dosimeter. Dose–volume histograms (DVHs), gamma maps and line profiles were used to evaluate the comparison.ResultsDVHs of gross tumour volume, clinical tumour volume and planning tumour volume for the PRESAGE® dosimeter and Pinnacle3 treatment planning system shows that both measured and calculated statistics were in agreement, with a value of 97.8% of the prescribed dose. Gamma map comparisons showed that all three distributions passed 95% at the ±3%/±3 mm criteria. Comparisons of isodose line distribution between the PRESAGE® dosimeter, EBT2 film and planning system demonstrated agreement, with an average difference of 1.5%.ConclusionsThis work demonstrated the feasibility of PRESAGE® to function as an anthropomorphic phantom and laid the foundation for research studies in PRESAGE®/optical-computed tomography three-dimensional dosimetry with the most complex anthropomorphic phantoms.

Photon beam attenuation characteristics of three commercial radiation therapy treatment couch-tops

2018 ◽  
Vol 17 (4) ◽  
pp. 377-383
Author(s):  
Hamza Wajid ◽  
Andre Fleck ◽  
Johnson Darko ◽  
Ernest Osei
Keyword(s):  
Radiation Therapy ◽  
Treatment Planning ◽  
Radiation Treatment ◽  
Photon Beam ◽  
Photon Beams ◽  
Radiation Treatment Planning ◽  
Beam Attenuation ◽  
Attenuation Characteristics ◽  
Therapy Treatment

AbstractAimThe purpose of the study was to investigate the detailed angularly dependent attenuation characteristics of three different commercial couch-tops: Varian IGRT, Qfix kVue Standard and Qfix kVue Dose Max couch-tops used in radiation therapy.Materials and methodsThe attenuation of photon beams by the treatment couch-tops was measured using a farmer chamber inserted at the centre of a 16 cm diameter cylindrical acrylic phantom for five different photon energies: 6 MV, 6FFF MV, 10 MV, 10FFF MV and 15 MV photon beams. The Varian IGRT couch-top has three different thicknesses thus attenuation measurements were done at the three different longitudinal locations. Measurements were made with the sliding support rails of the Qfix kVue Standard and Qfix kVue Dose Max couch-tops at both ‘rails-in’ and ‘rails-out’ positions. All measurements were taken for several projections through 360° movement of the gantry and for two different field sizes; 5×5 cm2 and 10×10 cm2.Results and findingsThe results indicate that the maximum attenuation of the Varian IGRT couch-top at the thin, medium and thick portions are 5·1, 5·7 and 8·9%, respectively, the Qfix kVue Standard couch with the rails-in and rails-out are 11·2 and 13·7%, respectively, and Qfix kVue Dose Max couch-top with rails-in and rails-out are 9·7 and 13·8%, respectively. The results from this study can be used to account for the couch-top attenuation during radiation treatment planning of patients treated with these couch-tops.

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