scholarly journals Daily dose to organs at risk predicts acute toxicity in pancreatic stereotactic radiotherapy

2020 ◽  
Vol 59 (8) ◽  
pp. 944-948
Author(s):  
Mauro Loi ◽  
Alba Magallon-Baro ◽  
Mustafa Suker ◽  
Casper Van Eijck ◽  
Mischa Hoogeman ◽  
...  
Keyword(s):  
At Risk ◽  
Acute Toxicity ◽  
Stereotactic Radiotherapy ◽  
Organs At Risk ◽  
Daily Dose

scholarly journals 70P 4D CT analysis of organs at risk (OARs) in stereotactic radiotherapy

2021 ◽  
Vol 16 (4) ◽  
pp. S733
Author(s):  
V. Nardone ◽  
F.M. Giugliano ◽  
A. Reginelli ◽  
S. Cappabianca ◽  
M. Mormile ◽  
...  
Keyword(s):  
At Risk ◽  
Stereotactic Radiotherapy ◽  
Organs At Risk ◽  
4D Ct ◽  
Ct Analysis

scholarly journals Dosimetric Validation of a GAN-Based Pseudo-CT Generation for MRI-Only Stereotactic Brain Radiotherapy

Cancers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 1082
Author(s):  
Vincent Bourbonne ◽  
Vincent Jaouen ◽  
Clément Hognon ◽  
Nicolas Boussion ◽  
François Lucia ◽  
...  
Keyword(s):  
At Risk ◽  
Brain Metastases ◽  
Stereotactic Radiotherapy ◽  
Organs At Risk ◽  
Treatment Plan ◽  
Ct Scans ◽  
Generative Adversarial Network ◽  
Electronic Density ◽  
Planning Ct ◽  
Synthetic Ct

Purpose: Stereotactic radiotherapy (SRT) has become widely accepted as a treatment of choice for patients with a small number of brain metastases that are of an acceptable size, allowing for better target dose conformity, resulting in high local control rates and better sparing of organs at risk. An MRI-only workflow could reduce the risk of misalignment between magnetic resonance imaging (MRI) brain studies and computed tomography (CT) scanning for SRT planning, while shortening delays in planning. Given the absence of a calibrated electronic density in MRI, we aimed to assess the equivalence of synthetic CTs generated by a generative adversarial network (GAN) for planning in the brain SRT setting. Methods: All patients with available MRIs and treated with intra-cranial SRT for brain metastases from 2014 to 2018 in our institution were included. After co-registration between the diagnostic MRI and the planning CT, a synthetic CT was generated using a 2D-GAN (2D U-Net). Using the initial treatment plan (Pinnacle v9.10, Philips Healthcare), dosimetric comparison was performed using main dose-volume histogram (DVH) endpoints in respect to ICRU 91 guidelines (Dmax, Dmean, D2%, D50%, D98%) as well as local and global gamma analysis with 1%/1 mm, 2%/1 mm and 2%/2 mm criteria and a 10% threshold to the maximum dose. t-test analysis was used for comparison between the two cohorts (initial and synthetic dose maps). Results: 184 patients were included, with 290 treated brain metastases. The mean number of treated lesions per patient was 1 (range 1–6) and the median planning target volume (PTV) was 6.44 cc (range 0.12–45.41). Local and global gamma passing rates (2%/2 mm) were 99.1 CI95% (98.1–99.4) and 99.7 CI95% (99.6–99.7) respectively (CI: confidence interval). DVHs were comparable, with no significant statistical differences regarding ICRU 91′s endpoints. Conclusions: Our study is the first to compare GAN-generated CT scans from diagnostic brain MRIs with initial CT scans for the planning of brain stereotactic radiotherapy. We found high similarity between the planning CT and the synthetic CT for both the organs at risk and the target volumes. Prospective validation is under investigation at our institution.

scholarly journals Multicatheter interstitial brachytherapy versus stereotactic radiotherapy with CyberKnife for accelerated partial breast irradiation: a comparative treatment planning study with respect to dosimetry of organs at risk

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
András Herein ◽  
Gábor Stelczer ◽  
Csilla Pesznyák ◽  
Georgina Fröhlich ◽  
Viktor Smanykó ◽  
...  
Keyword(s):  
At Risk ◽  
Stereotactic Radiotherapy ◽  
Organs At Risk ◽  
Contralateral Breast ◽  
Interstitial Brachytherapy ◽  
Accelerated Partial Breast Irradiation ◽  
Partial Breast Irradiation ◽  
Breast Irradiation ◽  
Ipsilateral Lung ◽  
Dose Volume

Abstract Background The aim of the study was to dosimetrically compare multicatheter interstitial brachytherapy (MIBT) and stereotactic radiotherapy with CyberKnife (CK) for accelerated partial breast irradiation (APBI) especially concerning the dose of organs at risk (OAR-s). Patients and methods Treatment plans of thirty-two MIBT and CK patients were compared. The OAR-s included ipsilateral non-target and contralateral breast, ipsilateral and contralateral lung, skin, ribs, and heart for left-sided cases. The fractionation was identical (4 x 6.25 Gy) in both treatment groups. The relative volumes (e.g. V100, V90) receiving a given relative dose (100%, 90%), and the relative doses (e.g. D0.1cm3, D1cm3) delivered to the most exposed small volumes (0.1 cm3, 1 cm3) were calculated from dose-volume histograms. All dose values were related to the prescribed dose (25 Gy). Results Regarding non-target breast CK performed slightly better than MIBT (V100: 0.7% vs. 1.6%, V50: 10.5% vs. 12.9%). The mean dose of the ipsilateral lung was the same for both techniques (4.9%), but doses irradiated to volume of 1 cm3 were lower with MIBT (36.1% vs. 45.4%). Protection of skin and rib was better with MIBT. There were no significant differences between the dose-volume parameters of the heart, but with MIBT, slightly larger volumes were irradiated by 5% dose (V5: 29.9% vs. 21.2%). Contralateral breast and lung received a somewhat higher dose with MIBT (D1cm3: 2.6% vs. 1.8% and 3.6% vs. 2.5%). Conclusions The target volume can be properly irradiated by both techniques with similar dose distributions and high dose conformity. Regarding the dose to the non-target breast, heart, and contralateral organs the CK was superior, but the nearby organs (skin, ribs, ipsilateral lung) received less dose with MIBT. The observed dosimetric differences were small but significant in a few parameters at the examined patient number. More studies are needed to explore whether these dosimetric findings have clinical significance.

Use of machine learning methods for prediction of acute toxicity in organs at risk following prostate radiotherapy

2011 ◽  
Vol 38 (6Part1) ◽  
pp. 2859-2867 ◽  
Author(s):  
Andrea Pella ◽  
Raffaella Cambria ◽  
Marco Riboldi ◽  
Barbara Alicja Jereczek-Fossa ◽  
Cristiana Fodor ◽  
...  
Keyword(s):  
Machine Learning ◽  
At Risk ◽  
Acute Toxicity ◽  
Organs At Risk ◽  
Learning Methods ◽  
Prostate Radiotherapy ◽  
Machine Learning Methods

PO-1693 4D CT analysis of organs at risk (OARs) in stereotactic radiotherapy

2021 ◽  
Vol 161 ◽  
pp. S1420
Author(s):  
V. Nardone ◽  
F.M. Giugliano ◽  
A. Reginelli ◽  
M. Mormile ◽  
L. Iadanza ◽  
...  
Keyword(s):  
At Risk ◽  
Stereotactic Radiotherapy ◽  
Organs At Risk ◽  
4D Ct ◽  
Ct Analysis

4D CT analysis of organs at risk (OARs) in stereotactic radiotherapy

2020 ◽  
Vol 151 ◽  
pp. 10-14
Author(s):  
Valerio Nardone ◽  
Francesca Maria Giugliano ◽  
Alfonso Reginelli ◽  
Angelo Sangiovanni ◽  
Maria Mormile ◽  
...  
Keyword(s):  
At Risk ◽  
Stereotactic Radiotherapy ◽  
Organs At Risk ◽  
4D Ct ◽  
Ct Analysis

scholarly journals Use of a Head-Tilting Baseplate During Tomotherapy to Shorten the Irradiation Time and Protect the Hippocampus and Lens in Hippocampal Sparing-Whole Brain Radiotherapy

2021 ◽  
Vol 20 ◽  
pp. 153303382098682
Author(s):  
Kosei Miura ◽  
Hiromasa Kurosaki ◽  
Nobuko Utsumi ◽  
Hideyuki Sakurai
Keyword(s):  
At Risk ◽  
Planning Target Volume ◽  
Irradiation Time ◽  
Organs At Risk ◽  
Absorbed Dose ◽  
Whole Brain Radiotherapy ◽  
Target Volume ◽  
Whole Brain ◽  
Brain Radiotherapy ◽  
Hippocampal Sparing

Purpose: The aim of this study is to comparatively examine the possibility of reducing the exposure dose to organs at risk, such as the hippocampus and lens, and improving the dose distribution of the planned target volume with and without the use of a head-tilting base plate in hippocampal-sparing whole-brain radiotherapy using tomotherapy. Methods: Five paired images of planned head computed tomography without and with tilt were analyzed. The hippocampus and planning target volume were contoured according to the RTOG 0933 contouring atlas protocol. The hippocampal zone to be avoided was delineated using a 5-mm margin. The prescribed radiation dose was 30 Gy in 10 fractions. The absorbed dose to planning target volume dose, absorbed dose to the organ at risk, and irradiation time were evaluated. The paired t-test was used to analyze the differences between hippocampal-sparing whole-brain radiotherapy with head tilts and without head tilts. Results: Hippocampal-sparing whole-brain radiotherapy with tilt was not superior in planning target volume doses using the homogeneity index than that without tilt; however, it showed better values, and for Dmean and D2%, the values were closer to 30 Gy. Regarding the hippocampus, dose reduction with tilt was significantly greater at Dmax, Dmean, and Dmin, whereas regarding the lens, it was significantly greater at Dmax and Dmin. The irradiation time was also predominantly shorter. Conclusion: In our study, a tilted hippocampal-sparing whole-brain radiotherapy reduced the irradiation time by >10%. Therefore, our study indicated that hippocampal-sparing whole-brain radiotherapy with tomotherapy should be performed with a tilt. The head-tilting technique might be useful during hippocampal-sparing whole-brain radiotherapy. This method could decrease the radiation exposure time, while sparing healthy organs, including the hippocampus and lens.

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