scholarly journals Benefit of Replanning in MR-guided Online Adaptive Radiation Therapy in the Treatment of Liver Metastasis

2021 ◽  
Author(s):  
Michael Mayinger ◽  
Roman Ludwig ◽  
Sebastian M. Christ ◽  
Riccardo Dal Bello ◽  
Alex Ryu ◽  
...  
Keyword(s):  
Radiation Therapy ◽  
Liver Metastases ◽  
Organs At Risk ◽  
Treatment Plan ◽  
Target Volume ◽  
Target Coverage ◽  
Adaptive Replanning ◽  
Pre Treatment ◽  
Grade 3 ◽  
Dosimetric Analysis

Abstract Purpose: To assess the effects of daily adaptive MR-guided replanning in stereotactic body radiation therapy (SBRT) of liver metastases based on a patient individual longitudinal dosimetric analysis. Methods: Fifteen patients assigned to SBRT for oligometastatic liver metastases underwent daily MR-guided target localization and on-table treatment plan re-optimization. Gross tumor volume (GTV) and organs at risk (OARs) were adapted to the anatomy-of-the-day. A reoptimized plan (RP) and a rigidly shifted baseline plan (sBP) without re-optimization were generated for each fraction. After extraction of DVH parameters for GTV, planning target volume (PTV), and OARs (stomach, duodenum, bowel, liver, heart) plans were compared on a per-patient basis.Results: Median pre-treatment GTV and PTV were 14.9 cc (interquartile range (IQR): 7.7 – 32.85) and 62.7 cc (IQR: 42.4 – 105.5) respectively. SBRT with RP improved PTV coverage (V100%) for 47/75 of the fractions and reduced doses to the most proximal OARs (D1cc, Dmean) in 33/75 fractions compared to sBP. RP significantly improved PTV coverage (V100%) for metastases within close proximity to an OAR by 4.0 % (≤ 0.2 cm distance; n = 7; p = 0.01), but only by 0.2% for metastases farther away from OAR (> 2 cm distance; n = 7; p = 0.37). No acute grade 3 treatment-related toxicities were observed.Conclusion: MR-guided online replanning SBRT improved target coverage and OAR sparing for liver metastases with a distance of more < 2 cm to the nearest luminal OAR. Only marginal improvements in target coverage were observed for target distant to critical OARs, indicating that these patients do not benefit from daily adaptive replanning.

scholarly journals Benefit of replanning in MR-guided online adaptive radiation therapy in the treatment of liver metastasis

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Michael Mayinger ◽  
Roman Ludwig ◽  
Sebastian M. Christ ◽  
Riccardo Dal Bello ◽  
Alex Ryu ◽  
...  
Keyword(s):  
Radiation Therapy ◽  
Liver Metastases ◽  
Organs At Risk ◽  
Treatment Plan ◽  
Target Volume ◽  
Target Coverage ◽  
Adaptive Replanning ◽  
Pre Treatment ◽  
Grade 3 ◽  
Dosimetric Analysis

Abstract Purpose To assess the effects of daily adaptive MR-guided replanning in stereotactic body radiation therapy (SBRT) of liver metastases based on a patient individual longitudinal dosimetric analysis. Methods Fifteen patients assigned to SBRT for oligometastatic liver metastases underwent daily MR-guided target localization and on-table treatment plan re-optimization. Gross tumor volume (GTV) and organs at risk (OARs) were adapted to the anatomy-of-the-day. A reoptimized plan (RP) and a rigidly shifted baseline plan (sBP) without re-optimization were generated for each fraction. After extraction of DVH parameters for GTV, planning target volume (PTV), and OARs (stomach, duodenum, bowel, liver, heart) plans were compared on a per-patient basis. Results Median pre-treatment GTV and PTV were 14.9 cc (interquartile range (IQR): 7.7–32.9) and 62.7 cc (IQR: 42.4–105.5) respectively. SBRT with RP improved PTV coverage (V100%) for 47/75 of the fractions and reduced doses to the most proximal OARs (D1cc, Dmean) in 33/75 fractions compared to sBP. RP significantly improved PTV coverage (V100%) for metastases within close proximity to an OAR by 4.0% (≤ 0.2 cm distance from the edge of the PTV to the edge of the OAR; n = 7; p = 0.01), but only by 0.2% for metastases farther away from OAR (> 2 cm distance; n = 7; p = 0.37). No acute grade 3 treatment-related toxicities were observed. Conclusions MR-guided online replanning SBRT improved target coverage and OAR sparing for liver metastases with a distance from the edge of the PTV to the nearest luminal OAR < 2 cm. Only marginal improvements in target coverage were observed for target distant to critical OARs, indicating that these patients do not benefit from daily adaptive replanning.

scholarly journals A dummy-run evaluation of postoperative hypofractionated intensity-modulated radiation therapy (POHIM-RT) trials for cervical cancer

2020 ◽  
Vol 62 (1) ◽  
pp. 149-154
Author(s):  
Won Kyung Cho ◽  
Heejung Kim ◽  
Won Park ◽  
Sang-Won Kim ◽  
Jongwon Kim ◽  
...  
Keyword(s):  
Cervical Cancer ◽  
Quality Assurance ◽  
Radiation Therapy ◽  
Organs At Risk ◽  
Treatment Plan ◽  
Intensity Modulated Radiation Therapy ◽  
Target Volume ◽  
Similarity Coefficients ◽  
Intensity Modulated ◽  
And Performance

Abstract The postoperative hypofractionated intensity-modulated radiation therapy (POHIM-RT) trial is a phase II study to evaluate toxicity following hypofractionated intensity modulated radiation therapy (IMRT) for cervical cancer. This study describes the results of a benchmark procedure for RT quality assurance of the POHIM-RT trial. Six participating institutions were provided computed tomography for RT planning and an IMRT plan for a sample and were instructed to delineate volumes, create a treatment plan and quality assurance (QA) plan, and submit the results of all procedures. The inter-institutional agreements on RT volume and plan results were evaluated using the kappa value and dice similarity coefficients. The simultaneous truth and performance level estimation (STAPLE) method was employed to generate a consensus target volume. The treatment volumes, organs-at-risk volumes, and results of the RT plan and QA reported by the institutions were acceptable and adhered well to the protocol. In terms of clinical target volume (CTV) delineation, there were differences between the institutions, particularly in vaginal cuff and paracolpium subsites. Consensus CTV was generated from the collected CTVs with the STAPLE method. The participating institutions showed considerable agreement regarding volume, dose and QA results. To improve CTV agreement in CTV, we provided feedback with images of the consensus target volume and detailed written guidelines for specific subsites that were the most heterogeneous.

scholarly journals Impact of fiducial markers placements on the delineation of target volumes in radiation therapy for oesophageal cancer: final results of the FIDUCOR study

2020 ◽  
Author(s):  
Laurence Moureau-Zabotto ◽  
F. Caillol ◽  
A. Autret ◽  
M. Gilabert ◽  
J. Guiramand ◽  
...  
Keyword(s):  
Radiation Therapy ◽  
Ct Scan ◽  
Positive Impact ◽  
Organs At Risk ◽  
Treatment Plan ◽  
Target Volume ◽  
Fiducial Markers ◽  
Distant Lymph Node Metastasis ◽  
Significant Difference ◽  
The Impact

Abstract Purpose This prospective monocentric phase II study (FIDUCOR-study) aimed at the assessment of the impact of fiducial markers (FMs) implantation on conformal chemo-radiation therapy (CRT) planning in esophageal carcinoma (EC) patients. Methods/materials Fifteen EC patients were enrolled in the study. Each patient underwent two simulation CT-scans before (CT1) and after (CT2) FMs implantation, in the same position. FMs (3 mm length gold markers, preloaded in a 22G needle) were implanted after sedation, under EUS and X-Ray guidance, and were placed at the tumor’s extremities, and in the visible lymph nodes. Target delineation and treatment plan were both performed first on CT1 with the assistance of, diagnosis-CT, gastroscopy- and EUS-details, and second on CT2 using FMs and CT-data. The value of FMs implantation was assessed by the difference of growth-tumor-volume (GTV) and clinical-target-volume (CTV) between CT1-based and CT2-based delineation. A significant difference was defined as a ≥5 mm-difference on axial(x) or coronal(y) slices, a ≥10mm-difference on sagittal slices, or a ≥20%-difference in GTV. The impact on dose distribution in organs at risk (OAR) (lung, heart, liver) was also studied. Results Between 09/2014 and 12/2015, 15 patients could achieve fiducial procedures, without any complication. One FM migration occurred. We observed a significant modification of the GTV-dimension in 100% of the cases (15/15, 95%CI: [78.2;100.0]), mainly due to a difference in sagittal dimension with a mean variation of 11.2 mm and a difference> 10 mm for 8/15 patients (53.3%). One patient had a significant isocenter displacement as high as 20 mm. The esophagus tumor was not seen on the CT-scan in one patient due to its small size. One patient had a distant lymph node metastasis not visible on CT-scan. We observed no significant impact on OAR distribution. Conclusion In our study, FMs-implantation appeared to have positive impact on accurate volume definition in EC-patients. Registration trial number NCT02526134 since the 06-18-2013 ; URL https://clinicaltrials.gov/ct2/show/NCT02526134

scholarly journals Differential Dose Distribution in Transition from 3-D CRT to IMRT Treatment Plans for Glioblastoma Multiforme' at Stage III or IV: A Clinical Study of a Brain Tumor

2018 ◽  
Vol 19 (1) ◽  
pp. 64
Author(s):  
Sadiq R Malik ◽  
Shohel Reza ◽  
MM Shakhawat Hossain
Keyword(s):  
Radiation Therapy ◽  
Dose Distribution ◽  
Selection Process ◽  
Organs At Risk ◽  
Treatment Plan ◽  
Target Volume ◽  
Conformity Index ◽  
Tumor Control ◽  
Treatment Plans

<p><span>Advancement in Cancer Therapy Technology (CTT) due to Software, Hardware and precise delivery of radiation dose has enhanced the quality of life of cancer patients. This report aims at the application of 3-D CRT (Three Dimensional Conformal Radiation Therapy) and IMRT (Intensity Modulated Radiation Therapy) for a quality of treatment. Other anatomical sites viz. Prostate, Lung, etc. may also be treated provided a better tool is applied for target delineation for which FUSION of CT and MRI images are used to ascertain differences in tissue density. This Fusion image of 3 mm slices offer accurate contouring of the tumor. The oncologist and/or physicist perform delineation of (I) GTV (Gross Tumor Volume), (II) CTV (Clinical Target Volume), (III) PTV (Planning Target Volume), (IV) TV (Treated Volume) and (V) OARs (Organs at Risk). This is done to secure conformal dose distribution and justify the clinical objectives of Tumor Control Probability (TCP) by reducing the normal tissue complication probability (NTCP). <span> </span><span> </span>The implication of this study outlines the fundamental goal of effective treatment procedures by comparing treatment plans of 3-D CRT and IMRT. Tolerance levels of dose to different organs are optimized by the analysis of random and systemic geometrical deviations, margin on target volumes, conformity index (CI), patient selection process and, of course, the shape and stage of target. The comparative parameters of treatment plans are segmented and tabulated to implicate the application of necessary tools to decide on a treatment plan for similar patients.</span></p><p><span>Bangladesh J. Nuclear Med. 19(1): 64-67, January 2016</span></p>

scholarly journals Dosimetric comparison between 3D conformal and intensity-modulated radiation therapy for prostate cancer

2010 ◽  
Vol 9 (2) ◽  
pp. 77-85 ◽  
Author(s):  
Courtney Buckey ◽  
Gregory Swanson ◽  
Sotirios Stathakis ◽  
Nikos Papanikolaou
Keyword(s):  
Radiation Therapy ◽  
Organs At Risk ◽  
External Beam Radiotherapy ◽  
Radiation Therapy Oncology Group ◽  
Intensity Modulated Radiation Therapy ◽  
Standard Of Care ◽  
Target Volume ◽  
Conformal Radiation Therapy ◽  
Intensity Modulated ◽  
3D Crt

AbstractBackground and Purpose: Intensity-modulated radiation therapy (IMRT) is considered by many to be the standard of care in the delivery of external-beam radiotherapy treatments to the prostate. The purpose of this study is to assess the validity of the purported benefits of IMRT.Materials and Methods: Treatment plans were produced for 10 patients using both 3D conformal radiation therapy (3D-CRT) and IMRT, utilising the dose constraints recommended by the Radiation Therapy Oncology Group (RTOG) 0415 protocol. Three IMRT modalities used in this study were linear accelerator based IMRT, helical tomotherapy, and serial tomotherapy. The prescription to the target, 76 Gy, was the same for all plans.Results: In general the 3D-CRT plans satisfied the RTOG criteria for planning target volume (PTV) coverage, and met or bettered the dose criteria for the organs at risk. PTV coverage was more homogeneous for the IMRT plans than the 3D-CRT plans but not significantly improved.Conclusions: Technically, because the IMRT plans required greater effort for the optimisation, longer treatment times and higher monitor units, the use of IMRT for the fulfilment of the protocol’s dosimetric goals was not justified using these constraints.

scholarly journals Local Search Algorithms for the Beam Angles’ Selection Problem in Radiotherapy

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Guillermo Cabrera-Guerrero ◽  
Nibaldo Rodriguez ◽  
Carolina Lagos ◽  
Enrique Cabrera ◽  
Franklin Johnson
Keyword(s):  
Radiation Therapy ◽  
Local Search ◽  
Organs At Risk ◽  
Treatment Plan ◽  
Search Algorithms ◽  
Steepest Descent ◽  
Beam Angle ◽  
Local Search Algorithms ◽  
Descent Algorithm ◽  
Steepest Descent Algorithm

One important problem in radiation therapy for cancer treatment is the selection of the set of beam angles radiation will be delivered from. A primary goal in this problem is to find a beam angle configuration (BAC) that leads to a clinically acceptable treatment plan. Further, this process must be done within clinically acceptable times. Since the problem of selecting beam angles in radiation therapy is known to be extremely hard to solve as well as time-consuming, both exact algorithms and population-based heuristics might not be suitable to solve this problem. In this paper, we compare two matheuristic methods based on local search algorithms, to approximately solve the beam angle optimisation problem (BAO). Although the steepest descent algorithm is able to find locally optimal BACs for the BAO problem, it takes too long before convergence, which is not acceptable in clinical practice. Thus, we propose to use a next descent algorithm that converges quickly to good quality solutions although no (local) optimality guarantee is given. We apply our two matheuristic methods on a prostate case which considers two organs at risk, namely, the rectum and the bladder. Results show that the matheuristic algorithm based on the next descent local search is able to quickly find solutions as good as the ones found by the steepest descent algorithm.

scholarly journals FDG-PET Improves Management of Patients with Colorectal Liver Metastases Allocated for Local Treatment: A Consecutive Prospective Study

2007 ◽  
Vol 96 (3) ◽  
pp. 209-213 ◽  
Author(s):  
M. Sørensen ◽  
F. V. Mortensen ◽  
M. Høyer ◽  
H. Vilstrup ◽  
S. Keiding ◽  
...  
Keyword(s):  
Liver Metastases ◽  
Fdg Pet ◽  
Colorectal Liver Metastases ◽  
Imaging Modality ◽  
Treatment Plan ◽  
Local Treatment ◽  
Liver Lesions ◽  
Term Survival ◽  
Pre Treatment

Background and Aim: Colorectal cancer is a common cancer in the Nordic countries and 50% of the patients develop liver metastases. Liver resection may result in long term survival. Proper staging is therefore essential and CT is the standard imaging modality. We examined whether additional FDG-PET improves therapeutic management of patients with colorectal liver metastases. Patients and Methods: Fifty-four consecutive patients were enrolled. Each patient had a treatment plan made based on our standard evaluation. The patients then had a PET scan and the treatment plan was re-evaluated, taking these results into account. Results: In 76% of the cases, PET did not change the treatment plan due to complete concordance with CT. In another 19% of the cases, the plan was altered due to finding of more liver lesions by PET than by CT (four patients), fewer or no liver lesions (three patients), and extrahepatic lesions not visible on CT (three patients). In 5% of the cases, non-concordance between PET and CT did not change the therapeutic plan. Conclusion: Pre-treatment FDG-PET, used supplementary to CT, improved the treatment plan in one fifth of the patients with colorectal liver metastases.

scholarly journals The Dosimetric Comparisons of CRT, IMRT, ARC, CRT+IMRT, and CRT+ARC of Postoperative Radiotherapy in IIIA-N2 Stage Non-Small-Cell Lung Cancer Patients

2019 ◽  
Vol 2019 ◽  
pp. 1-16
Author(s):  
Yanqiu Zhang ◽  
A’meng Han ◽  
Zhanzhao Fu ◽  
Shufeng Xu ◽  
Zijian Zhang
Keyword(s):  
Radiation Therapy ◽  
Organs At Risk ◽  
Postoperative Radiotherapy ◽  
Volumetric Modulated Arc Therapy ◽  
Target Volume ◽  
Imrt Plan ◽  
Stage Iiia ◽  
Conformal Radiation Therapy ◽  
Resected Nsclc ◽  
Nsclc Patients

Currently, studies about PORT in stage IIIA-N2 NSCLC patients in recent years have mostly adopted the conformal radiation therapy (CRT) technique, while other modern techniques such as intensity modulated radiation therapy (IMRT), volumetric modulated arc therapy (VMAT, hereinafter referred to as ARC), helical tomotherapy (HT), and so forth are also developing quickly. In this paper, we intended to compare the dosimetric characteristics of CRT, IMRT, ARC, CRT+IMRT, and CRT+ARC of PORT in stage IIIA-N2 NSCLC patients. Ten patients with stage IIIA-N2 completely resected NSCLC, whom were treated by PORT in the radiotherapy department of our hospital from January 1, 2017, to January 1, 2018, were randomly selected in this study. For each patient, the CRT plan, IMRT plan, ARC plan, CRT+IMRT plan, and CRT+ARC plan were designed separately on the same set of CT images. The isodose distribution and dose-volume histogram (DVH) of the five plans were compared to determine the dosimetric parameters of the targets, OAR (organs at risk), and the normal tissue (defined as body subtracted to PTV (planning target volume), B-P). No plan had absolute dosimetry advantages than any other plans. In clinical practice, the plans could be chosen according to their dosimetry characteristics.

Radiotherapy (RT) dose escalation study with concurrent cisplatin and S-1 in patients with inoperable stage III non-small cell lung cancer (NSCLC)

2009 ◽  
Vol 27 (15_suppl) ◽  
pp. 7542-7542
Author(s):  
H. Harada ◽  
M. Nishio ◽  
H. Murakami ◽  
F. Ohyanagi ◽  
T. Kozuka ◽  
...  
Keyword(s):  
Radiation Dose ◽  
Febrile Neutropenia ◽  
Organs At Risk ◽  
Performance Status ◽  
Target Volume ◽  
Stage Iii ◽  
Eligibility Criteria ◽  
Metastatic Node ◽  
Dose Escalation Study ◽  
Grade 3

7542 Background: Standard treatment for inoperable stage III NSCLC is concurrent chemoradiotherapy using 3-D conformal RT to a total dose of 60 Gy, but the outcome is still dismal with median survival time (MST) of 16 months and 5-year survival of 15%. We conducted a phase II trial using cisplatin, S-1 and concurrent RT of 60 Gy (J Clin Oncol 2008;26:a7556). MST (33months) was encouraging, however, local failure rate with this trial remained still high. The purpose of this study was to establish the recommended dose (RD) of RT with concurrent cisplatin and S-1. Methods: The eligibility criteria were: histologically or cytologically proven NSCLC, 20–75 years old, performance status 0–1, without any prior chemotherapy or RT. Patients were treated with cisplatin (60 mg/m2 on day 1) and S-1 (orally at 40 mg/m2/dose b.i.d., on days 1–14) repeated every 4 weeks for 4 cycles and RT was started on day 1. Radiation dose was escalated from 66 Gy in 33 fractions (Arm 1) to 70 Gy in 35 fractions (Arm 2), then 74 Gy in 37 fractions (Arm 3). The dose was to be escalated if DLTs were observed in 2 or less patients. The target volume of RT included primary tumor and metastatic node only and elective nodal irradiation was not performed. Dose constraints to the organs at risk were: the lung, V20 < 30%; the esophagus, mean dose < 34 Gy and V55 < 30%; the spinal cord, max dose < 50 Gy. Results: Six patients in each arm were enrolled. Two patients in Arm 1 experienced DLTs: one patient developed grade 3 febrile neutropenia, grade 3 mucositis in oral cavity and grade 3 diarrhea and one patient developed grade 3 febrile neutropenia. One patient in Arm 3 has not been completed evaluation yet. Otherwise no DLT was observed. Conclusions: The radiation dose of 74 Gy in 37 fractions with concurrent cisplatin and S-1 seemed to be tolerable and was judged to be the RD. This study is still open to accrue another six patients to confirm the safety of the RD. No significant financial relationships to disclose.

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