Evaluation of the correlation between dosimetric, geometric, and technical parameters of radiosurgery planning for multiple brain metastases

Camargo, André Vinícius de; Cao, Minsong; Silva, Diego da Cunha Silveira Alves da; Araújo, Raphael Leonardo Cunha de

doi:10.1002/acm2.13326

Cited by 3 publications

(5 citation statements)

References 21 publications

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“…No statistical correlation was observed between dosimetric and geometric variables and toxicities. The descriptive statistics of dosimetric, geometric, and technical variables have previously been published by our group[ 16 ].…”

Section: Resultsmentioning

confidence: 99%

“…According to dosimetric, geometric, and technical variables, the lack of correlation with toxicities does not imply they do not impact each other, especially considering dosimetric variables used for planning approval. It is known that the volume of targets, number of lesions, distance between lesions, and the isocenter impact these plan evaluation indexes[ 16 , 23 - 25 ]. What can be observed is that the indication of isolated radiosurgery for multiple brain metastases was safe, considering that the technique achieved dosimetric values good enough not to cause collateral effects.…”

Section: Discussionmentioning

confidence: 99%

“…Technical variables included were the total number of arcs, coplanar or non-coplanar arcs, number of non-coplanar arcs if used, and number of isocenters. The correlations between the dosimetric, geometric, and technical variables collected for this work were previously published by our group[ 16 ].…”

Section: Methodsmentioning

confidence: 99%

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Treatment of patients with multiple brain metastases by isolated radiosurgery: Toxicity and survival

de Camargo,

de Mattos,

Kawasaki

et al. 2023

World J Clin Oncol

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BACKGROUND Radiosurgery for multiple brain metastases has been more reported recently without using whole-brain radiotherapy. Nevertheless, the sparsity of the data still claims more information about toxicity and survival and their association with both dosimetric and geometric aspects of this treatment. AIM To assess the toxicity and survival outcome of radiosurgery in patients with multiple (four or more lesions) brain metastases. METHODS In a single institution, data were collected retrospectively from patients who underwent radiosurgery to treat brain metastases from diverse primary sites. Patients with 4-21 brain metastases were treated with a single fraction with a dose of 18 Gy or 20 Gy. The clinical variables collected were relevant to toxicity, survival, treatment response, planning, and dosimetric variables. The Spearman’s rank correlation coefficients, Mann-Whitney test, Kruskal-Wallis test, and Log-rank test were used according to the type of variable and outcomes. RESULTS From August 2017 to February 2020, 55 patients were evaluated. Headache was the most common complaint (38.2%). The median overall survival (OS) for patients with karnofsky performance status (KPS) > 70 was 8.9 mo, and this was 3.6 mo for those with KPS ≤ 70 ( P = 0.047). Patients with treated lesions had a median progression-free survival of 7.6 mo. There were no differences in OS (19.7 vs 9.5 mo) or progression-free survival (10.6 vs 6.3 mo) based on prior irradiation. There was no correlation found between reported toxicities and planning, dosimetric, and geometric variables, implying that no additional significant toxicity risks appear to be added to the treatment of multiple (four or more) lesions. CONCLUSION No associations were found between the evaluated toxicities and the planning dosimetric parameters, and no differences in survival rates were detected based on previous treatment status.

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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Treatment of patients with multiple brain metastases by isolated radiosurgery: Toxicity and survival

de Camargo,

de Mattos,

Kawasaki

et al. 2023

World J Clin Oncol

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“…To reduce variability in the HB contouring, recommendations, as reported in a study [11] were followed to evaluate the risk of brain necrosis, excluding certain structures in the dosimetric evaluation such as the brainstem and GTVs. This analysis presented shows that V 12 varies regarding if it is local, or global and if the evaluation is for WB or HB.…”

Section: Discussionmentioning

confidence: 99%

“…SRS requires high-dose delivery, high-dose gradient, and sub-millimeter precision. Thus, it is important to carefully define the sources of uncertainty [9][10][11][12][13][14][15][16] to ensure both coverage and maximize sparing. In particular, the impact of intra-and interfractional setup shifts on the dose distribution has been studied for rotations and translations [17][18][19][20][21][22].…”

Section: Introductionmentioning

confidence: 99%

Assessment of PTV margin adequacy for single isocenter multiple brain metastases using genetic algorithms

Rojas-López

Venencia²,

Chesta

et al. 2023

Biomed. Phys. Eng. Express

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Purpose: To study the impact on dose coverage and the dose to the healthy tissue applying optimized margins in single isocenter multiple brain metastases radiosurgery (SIMM-SRS) in linac machine based on setup rotations/translations induced errors calculated by a genetic algorithm (GA).Method: The following quality indices of SIMM-SRS were analyzed for 32 plans (256 lesions): Paddick conformity index (PCI), gradient index (GI), maximum (Dmax) and mean (Dmean) doses, local and global V12 for the healthy brain. A GA based on Python packages were used to determine the maximum shift produced by induced errors of 0.2º/0.2 mm, and 0.5º/0.5 mm in 6 degrees of freedom.Results: In terms of Dmax, and Dmean, the quality of the optimized-margin plans remains unchanged (p>0.072) concerning the original plan. However, considering the 0.5º/0.5 mm plans, PCI and GI decreased for ≥ 10 metastases, and local, and global V12 increased considerably in all cases. To consider 0.2º/0.2 mm plans, PCI and GI get worse but local, and global V12 improved in all cases.Conclusion: GA facilities to find the individualized margins automatically among the number of possible permutations of the setup order. The user-dependent margins are avoided. This computational approach takes into account more SRS sources of uncertainty, enabling the protection of the healthy brain by “smartly” reducing the margins, and maintaining clinically acceptable target volumes’ coverage in most cases.

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Insights into the dosimetric and geometric characteristics of stereotactic radiosurgery for multiple brain metastases: A systematic review

Mukwada,

Chamunyonga,

Rowshanfarzad

et al. 2024

PLoS ONE

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Background GammaKnife (GK) and CyberKnife (CK) have been the mainstay stereotactic radiosurgery (SRS) solution for multiple brain metastases (MBM) for several years. Recent technological advancement has seen an increase in single-isocentre C-arm linac-based SRS. This systematic review focuses on dosimetric and geometric insights into contemporary MBM SRS and thereby establish if linac-based SRS has matured to match the mainstay SRS delivery systems. Methods The PubMed, Web of Science and Scopus databases were interrogated which yielded 891 relevant articles that narrowed to 20 articles after removing duplicates and applying the inclusion and exclusion criteria. Primary studies which reported the use of SRS for treatment of MBM SRS and reported the technical aspects including dosimetry were included. The review was limited to English language publications from January 2015 to August 2023. Only full-length papers were included in the final analysis. Opinion papers, commentary pieces, letters to the editor, abstracts, conference proceedings and editorials were excluded. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed. The reporting of conformity indices (CI) and gradient indices, V12Gy, monitor units and the impact of translational and rotational shifts were extracted and analysed. Results The single-isocentre technique for MBM dominated recent SRS studies and the most studied delivery platforms were Varian. The C-arm linac-based SRS plan quality and normal brain tissue sparing was comparable to GK and CK and in some cases better. The most used nominal beam energy was 6FFF, and optimised couch and collimator angles could reduce mean normal brain dose by 11.3%. Reduction in volume of the healthy brain receiving a certain dose was dependent on the number and size of the metastases and the relative geometric location. GK and CK required 4.5–8.4 times treatment time compared with linac-based SRS. Rotational shifts caused larger changes in CI in C-arm linac-based single-isocentre SRS. Conclusion C-arm linac-based SRS produced comparable MBM plan quality and the delivery is notably shorter compared to GK and CK SRS.

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Evaluation of the correlation between dosimetric, geometric, and technical parameters of radiosurgery planning for multiple brain metastases

Cited by 3 publications

References 21 publications

Treatment of patients with multiple brain metastases by isolated radiosurgery: Toxicity and survival

Treatment of patients with multiple brain metastases by isolated radiosurgery: Toxicity and survival

Assessment of PTV margin adequacy for single isocenter multiple brain metastases using genetic algorithms

Insights into the dosimetric and geometric characteristics of stereotactic radiosurgery for multiple brain metastases: A systematic review

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