Evaluation of dose distribution to organs-at-risk in a prospective phase 1 trial of pembrolizumab and multi-site stereotactic body radiotherapy (SBRT)

2021 ◽  
Author(s):  
Annie Xiao ◽  
Jason J. Luke ◽  
Julien Partouche ◽  
Ted Karrison ◽  
Steven Chmura ◽  
...  
Keyword(s):  
At Risk ◽  
Stereotactic Body Radiotherapy ◽  
Dose Distribution ◽  
Organs At Risk ◽  
Phase 1 ◽  
Phase 1 Trial ◽  
Prospective Phase

scholarly journals Repeat radiation with bevacizumab and minocycline in bevacizumab-refractory high grade gliomas: a prospective phase 1 trial

2020 ◽  
Vol 148 (3) ◽  
pp. 577-585
Author(s):  
Adam L. Cohen ◽  
Christopher J. Anker ◽  
Brett Johnson ◽  
Lindsay M. Burt ◽  
Dennis C. Shrieve ◽  
...  
Keyword(s):  
Phase 1 ◽  
High Grade ◽  
Phase 1 Trial ◽  
Prospective Phase ◽  
High Grade Gliomas

scholarly journals Dosimetric and radiobiological comparison of treatment plan between CyberKnife and EDGE in stereotactic body radiotherapy for pancreatic cancer

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Zhi-tao Dai ◽  
Li Ma ◽  
Ting-ting Cao ◽  
Lian Zhu ◽  
Man Zhao ◽  
...  
Keyword(s):  
Pancreatic Cancer ◽  
Spinal Cord ◽  
Stereotactic Body Radiotherapy ◽  
Dose Distribution ◽  
Normal Tissue ◽  
Organs At Risk ◽  
Treatment Plan ◽  
Locally Advanced ◽  
Conformity Index ◽  
Homogeneous Dose

AbstractTo perform a comparison of the different stereotactic body radiotherapy (SBRT) plans between the Varian EDGE and CyberKnife (CK) systems for locally advanced unresectable pancreatic cancer. Fifteen patients with pancreatic cancer were selected in this study. The median planning target volume (PTV) was 28.688 cm3 (5.736–49.246 cm3). The SBRT plans for the EDGE and CK were generated in the Eclipse and Multiplan systems respectively with the same contouring and dose constrains for PTV and organs at risk (OARs). Dose distributions in PTV were evaluated in terms of coverage, conformity index (CI), new conformity index (nCI), homogeneity index (HI), and gradient index (GI). OARs, including spinal cord, bowel, stomach, duodenum and kidneys were statistically evaluated by different dose-volume metrics and equivalent uniform dose (EUD). The volume covered by the different isodose lines (ISDL) ranging from 10 to 100% for normal tissue were also analyzed. All SBRT plans for EDGE and CK met the dose constraints for PTV and OARs. For the PTV, the dosimetric metrics in EDGE plans were lower than that in CK, except that D99 and GI were slightly higher. The EDGE plans with lower CI, nCI and HI were superior to generate more conformal and homogeneous dose distribution for PTV. For the normal tissue, the CK plans were better at OARs sparing. The radiobiological indices EUD of spinal cord, duodenum, stomach, and kidneys were lower for CK plans, except that liver were higher. The volumes of normal tissue covered by medium ISDLs (with range of 20–70%) were lower for CK plans while that covered by high and low ISDLs were lower for EDGE plans. This study indicated that both EDGE and CK generated equivalent plan quality, and both systems can be considered as beneficial techniques for SBRT of pancreatic cancer. EDGE plans offered more conformal and homogeneous dose distribution for PTV, while the CK plans could minimize the exposure of OARs.

scholarly journals Toxicities of Organs at Risk in the Mediastinal and Hilar Regions Following Stereotactic Body Radiotherapy for Centrally Located Lung Tumors

2014 ◽  
Vol 9 (9) ◽  
pp. 1370-1376 ◽  
Author(s):  
Shuichi Nishimura ◽  
Atsuya Takeda ◽  
Naoko Sanuki ◽  
Satoshi Ishikura ◽  
Yohei Oku ◽  
...  
Keyword(s):  
At Risk ◽  
Stereotactic Body Radiotherapy ◽  
Organs At Risk ◽  
Lung Tumors

Evaluation of plan optimisers in prostate VMAT using the dose distribution index

2019 ◽  
Vol 18 (4) ◽  
pp. 323-328 ◽  
Author(s):  
James C. L. Chow ◽  
Runqing Jiang ◽  
Lu Xu
Keyword(s):  
At Risk ◽  
Dose Distribution ◽  
Organs At Risk ◽  
Volumetric Modulated Arc Therapy ◽  
Target Volume ◽  
Weighting Factor ◽  
Target Coverage ◽  
Dose Volume Histograms ◽  
Dose Volume ◽  
Distribution Index

AbstractPurpose:Dose distribution index (DDI) is a treatment planning evaluation parameter, reflecting dosimetric information of target coverage that can help to spare organs at risk (OARs) and remaining volume at risk (RVR). The index has been used to evaluate and compare prostate volumetric modulated arc therapy (VMAT) plans using two different plan optimisers, namely photon optimisation (PO) and its predecessor, progressive resolution optimisation (PRO).Materials and methods:Twenty prostate VMAT treatment plans were created using the PO and PRO in this retrospective study. The 6 MV photon beams and a dose prescription of 78 Gy/39 fractions were used in plans with the same dose–volume criteria for plan optimisation. Dose–volume histograms (DVHs) of the planning target volume (PTV), as well as of OARs such as the rectum, bladder, left and right femur were determined in each plan. DDIs were calculated and compared for plans created by the PO and PRO based on DVHs of the PTV and all OARs.Results:The mean DDI values were 0·784 and 0·810 for prostate VMAT plans created by the PO and PRO, respectively. It was found that the DDI of the PRO plan was about 3·3% larger than the PO plan, which means that the dose distribution of the target coverage and sparing of OARs in the PRO plan was slightly better. Changing the weighting factors in different OARs would vary the DDI value by ∼7%. However, for plan comparison based on the same set of dose–volume criteria, the effect of weighting factor can be neglected because they were the same in the PO and PRO.Conclusions:Based on the very similar DDI values calculated from the PO and PRO plans, with the DDI value in the PRO plan slightly larger than that of the PO, it may be concluded that the PRO can create a prostate VMAT plan with slightly better dose distribution regarding the target coverage and sparing of OARs. Moreover, we found that the DDI is a simple and comprehensive dose–volume parameter for plan evaluation considering the target, OARs and RVR.

Stereotactic body radiotherapy for T1 glottic cancer: dosimetric data in 27 consecutive patients

2021 ◽  
pp. 030089162110004
Author(s):  
Giuseppe Sanguineti ◽  
Raul Pellini ◽  
Antonello Vidiri ◽  
Simona Marzi ◽  
Pasqualina D’Urso ◽  
...  
Keyword(s):  
Stereotactic Body Radiotherapy ◽  
Organs At Risk ◽  
Glottic Cancer ◽  
True Vocal Cord ◽  
Dosimetric Data ◽  
Planning Treatment ◽  
Target Volumes ◽  
Treatment Volume ◽  
Planning Treatment Volume ◽  
Prospective Phase

Aim: Because the clinical feasibility of stereotactic body radiotherapy (SBRT) for early glottic cancer (T1) is controversial, we report dosimetric results in 27 consecutive patients from a prospective phase I and II study that started in 2017. Methods: In our approach, only the parts of the true vocal cord containing cancer and those immediately adjacent are planned to be treated to 36 Gy and 30 Gy, respectively, in 3 fractions. Several dosimetric metrics for both target volumes and organs at risk were extracted from individual plans and results were compared to those achieved by other authors in a similar setting. Results: Proper coverage was reached at planning in 2/3 of planning treatment volume 30 Gy, but only 4 planning treatment volume 36 Gy; conversely, the maximum dose objective was met for most of the patients on either arytenoid cartilage, but this was not the case for 51.9% and 96.3% of cricoid and thyroid cartilages, respectively. Our dosimetric results are similar to if not better than those achieved by others. Conclusion: SBRT in 3 fractions for T1 glottic lesions is dosimetrically challenging. Clinical validation is awaited.

Toxicity and Efficacy of Stereotactic Body Radiotherapy for Ultra-central Lung Tumours: a Single Institution Real Life Experience

2021 ◽  
Author(s):  
Elodie GUILLAUME ◽  
Ronan TANGUY ◽  
Myriam AYADI ◽  
Line CLAUDE ◽  
Coralie MONCHARMONT ◽  
...  
Keyword(s):  
At Risk ◽  
Local Control ◽  
Survival Data ◽  
Stereotactic Body Radiotherapy ◽  
Life Experience ◽  
Organs At Risk ◽  
Prospective Trial ◽  
Real Life ◽  
Lung Tumour ◽  
Lung Tumours

Abstract Purpose: The use of stereotactic body radiotherapy (SBRT) to treat ultra-central lung tumours remains more controversial than for peripheral and central tumours. We carried out a study about SBRT in patients with ultra-central lung tumours treated in our Cancer Centre. Our objectives were to assess toxicities, local control (LC) rate and survival data.Methods: We conducted a retrospective and monocentric study about 74 patients with an ultra-central lung tumour, consecutively treated between 2012 and 2018. Ultra-central tumours were defined as tumours whose PTV (planning target volume) overlapped one of the following organs at risk (OAR): the trachea, right and left main bronchi, intermediate bronchus, lobe bronchi, oesophagus, heart. Patients with primary or secondary tumour were enrolled in the study.Results: Median follow-up was 25 months. Two patients (2.7%) showed grade 3 toxicity. No grade 4 or 5 toxicity was observed. Eleven per cent of patients experienced primary local relapse. Local control rate was 96.7% at 1 year and 87.6% at 2 years. Median progression free survival (PFS) was 12 months. Median overall survival (OS) was 31 months. Conclusions: SBRT for ultra-central tumours remains safe and effective. Thus, SBRT can be considered to be well tolerated as long as protecting organs at risk remains treatment planning priority. Besides, as the results of ongoing prospective trial have not been published yet, SBRT for ultra-central tumours should be performed with caution.

Analysis of rectal dose during prostate stereotactic body radiotherapy in MR-guided radiotherapy.

2021 ◽  
Vol 39 (6_suppl) ◽  
pp. 242-242
Author(s):  
Kobika Sritharan ◽  
Alex Dunlop ◽  
Adam Mitchell ◽  
Jonathan Mohajer ◽  
Gillian Smith ◽  
...  
Keyword(s):  
At Risk ◽  
Stereotactic Body Radiotherapy ◽  
Organs At Risk ◽  
Treatment Plan ◽  
Adaptive Radiotherapy ◽  
Post Treatment ◽  
Rectal Dose ◽  
Dose Constraint ◽  
Fraction Dose ◽  
Rectal Filling

242 Background: The Unity MR-Linac combines a 7-MV Linac with 1.5T magnetic resonance (MR) imaging capability and it enables adaptive radiotherapy, whereby the target and organs at risk are recontoured and a plan is optimised daily. During treatment a session MR image is taken first, on which the target and organs-at-risk are contoured, and a plan created. A verification image is taken prior to dose delivery to identify intra-fractional changes. If present, the daily treatment plan is shifted to reflect the anatomy. A post-treatment image is acquired at the end of treatment. This study evaluates the dosimetric changes to the rectum caused by intra-fractional changes during treatment delivery for prostate stereotactic body radiotherapy (SBRT) calculated on the verification and post-treatment images. Methods: The first five patients treated on the MR-Linac with 5-fraction SBRT to the prostate are included in this study. For each patient, the rectum was contoured on the verification and post-treatment MR images for each of the five fractions. The dose delivered to the rectum with the original treatment plan was then calculated on each image and the V36Gy rectal dose constraint was noted. Results: Out of the 25 fractions, a post treatment image was not performed in one fraction; 24 fractions were therefore analysed in total. The rectal V36Gy dose constraint exceeded the mandatory target of 2cc on 50% of the verification images and 46% of the post-treatment images. In 6 fractions the rectal V36Gy was greater than 2cc on both the verification and post-treatment images suggesting this rectal constraint was exceeded throughout treatment. In 17% of patients, the volume of rectum receiving 36Gy increased at each timepoint an image was taken during the treatment workflow. Conclusions: The rectal V36Gy dose constraint is susceptible to minor changes in rectal filling, which may often lead to higher than the accepted dose constraint. Thus, a single planning CT scan is unlikely to be representative of dose delivered. Adaptive radiotherapy can reduce this uncertainty somewhat, but intra-fraction dose re-optimisation would be required to ensure the rectal V36Gy remains acceptable at all times.

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