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PURPOSE: The purpose of this study is to investigate inter-planner plan quality variability using a manual forward planning (MFP)- or fast inverse planning (FIP, Lightning)-approach for single brain lesions treated with the Gamma Knife® (GK) Icon™. METHODS: Thirty patients who were previously treated with GK stereotactic radiosurgery or radiotherapy were selected and divided into three groups (post-operative resection cavity, intact brain metastasis, and vestibular schwannoma [10 patients per group]). Clinical plans for the 30 patients were generated by multiple planners using FIP only (1), a combination of FIP and MFP (12), and MFP only (17). Three planners (Senior, Junior, and Novice) with varying experience levels re-planned the 30 patients using MFP and FIP (two plans per patient) with planning time limit of 60 min. Statistical analysis was performed to compare plan quality metrics (Paddick conformity index, gradient index, number of shots, prescription isodose line, target coverage, beam-on-time (BOT), and organs-at-risk doses) of MFP or FIP plans among three planners and to compare plan quality metrics between each planners MFP/FIP plans and clinical plans. Variability in FIP parameter settings (BOT, low dose, and target max dose) and in planning time among the planners was also evaluated. RESULTS: Variations in plan quality metrics of FIP plans among three planners were smaller than those of MFP plans for all three groups. Juniors MFP plans were the most comparable to the clinical plans, whereas Seniors and Novices MFP plans were superior and inferior, respectively. All three planners FIP plans were comparable or superior to the clinical plans. Differences in FIP parameter settings among the planners were observed. Planning time was shorter and variations in planning time among the planners were smaller for FIP plans in all three groups. CONCLUSIONS: The FIP approach is less planner dependent and more time-honored than the MFP approach.

Purpose: The purpose of this study is to investigate inter‐planner plan quality variability using a manual forward planning (MFP)‐ or fast inverse planning (FIP, Lightning)‐approach for single brain lesions treated with the Gamma Knife® (GK) Icon™. Methods: Thirty patients who were previously treated with GK stereotactic radiosurgery or radiotherapy were selected and divided into three groups (post‐operative resection cavity, intact brain metastasis, and vestibular schwannoma [10 patients per group]). Clinical plans for the 30 patients were generated by multiple planners using FIP only (1), a combination of FIP and MFP (12), and MFP only (17). Three planners (Senior, Junior, and Novice) with varying experience levels re‐planned the 30 patients using MFP and FIP (two plans per patient) with planning time limit of 60 min. Statistical analysis was performed to compare plan quality metrics (Paddick conformity index, gradient index, number of shots, prescription isodose line, target coverage, beam‐on‐time (BOT), and organs‐at‐risk doses) of MFP or FIP plans among three planners and to compare plan quality metrics between each planner's MFP/FIP plans and clinical plans. Variability in FIP parameter settings (BOT, low dose, and target max dose) and in planning time among the planners was also evaluated. Results: Variations in plan quality metrics of FIP plans among three planners were smaller than those of MFP plans for all three groups. Junior's MFP plans were the most comparable to the clinical plans, whereas Senior's and Novice's MFP plans were superior and inferior, respectively. All three planners' FIP plans were comparable or superior to the clinical plans. Differences in FIP parameter settings among the planners were observed. Planning time was shorter and variations in planning time among the planners were smaller for FIP plans in all three groups. Conclusions: The FIP approach is less planner dependent and more time‐honored than the MFP approach. [ABSTRACT FROM AUTHOR]

Surgically targeted radiation therapy (STaRT) with Cesium-131 seeds embedded in a collagen tile is a promising treatment for recurrent brain metastasis. In this study, the biological effective doses (BED) for normal and target tissues from STaRT plans were compared with those of external beam radiotherapy (EBRT) modalities. Nine patients (n = 9) with 12 resection cavities (RCs) who underwent STaRT (cumulative physical dose of 60 Gy to a depth of 5 mm from the RC edge) were replanned with CyberKnifeⓇ (CK), Gamma KnifeⓇ (GK), and intensity modulated proton therapy (IMPT) using an SRT approach (30 Gy in 5 fractions). Statistical significance comparing D95% and D90% in BED 10Gy (BED 10Gy 95% and BED 10Gy 90%) and to RC + 0 to + 5 mm expansion margins, and parameters associated with radiation necrosis risk (V8 3Gy , V10 3Gy , V12 3Gy and V24 3Gy) to the normal brain were evaluated by a Wilcoxon-signed rank test. For RC + 0 mm, median BED 10Gy 90% for STaRT (90.1 Gy 10 , range: 64.1–140.9 Gy 10) was significantly higher than CK (74.3 Gy 10 , range:59.3–80.4 Gy 10 , p = 0.04), GK (69.4 Gy 10 , range: 59.8–77.1 Gy 10 , p = 0.005), and IMPT (49.3 Gy 10 , range: 49.0–49.7 Gy 10 , p = 0.003), respectively. However, for the RC + 5 mm, the median BED 10Gy 90% for STaRT (34.1 Gy 10 , range: 22.2–59.7 Gy 10) was significantly lower than CK (44.3 Gy 10 , range: 37.8–52.4 Gy 10), and IMPT (46.6 Gy 10 , range: 45.1–48.5 Gy 10), respectively, but not significantly different from GK (34.1 Gy 10 , range: 22.8–47.0 Gy 10). The median V24 3Gy was significantly higher in CK (11.7 cc, range: 4.7–20.1 cc), GK(6.2 cc, range: 2.3–11.9 cc) and IMPT (19.9 cc, range: 11.1–36.6 cc) compared to STaRT (1.1 cc, range: 0.0–7.8 cc) (p < 0.01). This comparative analysis suggests a STaRT approach may treat recurrent brain tumors effectively via delivery of higher radiation doses with equivalent or greater BED up to at least 3 mm from the RC edge as compared to EBRT approaches. [ABSTRACT FROM AUTHOR]

Abstract: Alpha DaRT is a new alpha radiation treatment for treating solid tumors and is currently being evaluated through clinical trials worldwide. Being a novel radiation treatment, it is important to discuss the safety considerations and procedures that are needed to ensure safe use of this unique approach. The objective of this article is to provide a set of recommendations-radiation safety best practices that were developed based on operational and clinical experience., (Copyright © 2024 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the Health Physics Society.)

To assess the impact of Strut Adjusted Volume Implant (SAVI) catheter digitization variability on dosimetric evaluation parameters of HDR breast brachytherapy treatment plans. Four clinically approved SAVI cases were chosen for this digitization variability analysis. All patients were implanted with 6-1 SAVI device. Six experienced physicists independently digitized SAVI catheters. Plans utilizing significant peripheral loading were used for this study where SAVI catheters were near the chest wall and/or skin. After digitization was completed for each case by each physicist, the original clinical dwell times were copied over for comparison. This ensured that only variability among plans is the digitization of SAVI catheters by different users. The original plan that went through two physicists' checks and one physician's review was considered the "ground truth" plan to which all other plans were compared. Plans were evaluated on planning parameters for lumpectomy cavity's PTV&#95;Eval D90, V150, V200 and for the OARs (Chest-Wall/Ribs and Skin), on D 0.03cc , D 0.1cc , D 1cc , D 2cc . Additionally, a visualization window setting-based uncertainty test was performed on the same 4 cases. Our results showed that the average and maximum dwell positional digitization uncertainties were 0.36 and 0.75 mm, respectively. Average PTV&#95;Eval D90 was 97.11+/-2.93 %, V150 was 23.10+/-4.25 cc, V200 was 11.88+/-1.93 cc. All OAR constraints were met on all plans - Chest-Wall/Ribs (CW/Ribs) and Skin D 0.03cc was 103.40+/-9.23 % and 93.60+/-6.14 %, respectively. Aggregate analysis across all plans shows a clinically nonsignificant spread around the mean for all parameters considered. The robustness of SAVI treatment plans to minor variation in catheter digitization was proved through our multiuser study. Our study showed that SAVI planning constraints are stable within reasonable variation of digitization differences. Such uncertainty analysis is useful in standardization of digitization practices in a department and in defining action levels on digitization fixing request during a 2nd check., Competing Interests: Declaration of competing interest All authors and contributors involved in this process of carrying out this or writing the manuscript for this study have no conflicts of interests to disclose. Cite Sources of Support (if applicable): This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors., (Copyright © 2024. Published by Elsevier Inc.)

Purpose: The purpose of this study is to investigate inter-planner plan quality variability using a manual forward planning (MFP)- or fast inverse planning (FIP, Lightning)-approach for single brain lesions treated with the Gamma Knife ® (GK) Icon™., Methods: Thirty patients who were previously treated with GK stereotactic radiosurgery or radiotherapy were selected and divided into three groups (post-operative resection cavity, intact brain metastasis, and vestibular schwannoma [10 patients per group]). Clinical plans for the 30 patients were generated by multiple planners using FIP only (1), a combination of FIP and MFP (12), and MFP only (17). Three planners (Senior, Junior, and Novice) with varying experience levels re-planned the 30 patients using MFP and FIP (two plans per patient) with planning time limit of 60 min. Statistical analysis was performed to compare plan quality metrics (Paddick conformity index, gradient index, number of shots, prescription isodose line, target coverage, beam-on-time (BOT), and organs-at-risk doses) of MFP or FIP plans among three planners and to compare plan quality metrics between each planner's MFP/FIP plans and clinical plans. Variability in FIP parameter settings (BOT, low dose, and target max dose) and in planning time among the planners was also evaluated., Results: Variations in plan quality metrics of FIP plans among three planners were smaller than those of MFP plans for all three groups. Junior's MFP plans were the most comparable to the clinical plans, whereas Senior's and Novice's MFP plans were superior and inferior, respectively. All three planners' FIP plans were comparable or superior to the clinical plans. Differences in FIP parameter settings among the planners were observed. Planning time was shorter and variations in planning time among the planners were smaller for FIP plans in all three groups., Conclusions: The FIP approach is less planner dependent and more time-honored than the MFP approach., (© 2023 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, LLC on behalf of The American Association of Physicists in Medicine.)