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  • 1
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    In vivo dose measurement using TLDs and MOSFET dosimeters for cardiac radiosurgery
    Wiley ; 2012
    In:  Journal of Applied Clinical Medical Physics Vol. 13, No. 3 ( 2012-05), p. 190-203
    Details
    In: Journal of Applied Clinical Medical Physics, Wiley, Vol. 13, No. 3 ( 2012-05), p. 190-203
    Abstract: In vivo measurements were made of the dose delivered to animal models in an effort to develop a method for treating cardiac arrhythmia using radiation. This treatment would replace RF energy (currently used to create cardiac scar) with ionizing radiation. In the current study, the pulmonary vein ostia of animal models were irradiated with 6 MV X‐rays in order to produce a scar that would block aberrant signals characteristic of atrial fibrillation. The CyberKnife radiosurgery system was used to deliver planned treatments of 20–35 Gy in a single fraction to four animals. The Synchrony system was used to track respiratory motion of the heart, while the contractile motion of the heart was untracked. The dose was measured on the epicardial surface near the right pulmonary vein and on the esophagus using surgically implanted TLD dosimeters, or in the coronary sinus using a MOSFET dosimeter placed using a catheter. The doses measured on the epicardium with TLDs averaged 5% less than predicted for those locations, while doses measured in the coronary sinus with the MOSFET sensor nearest the target averaged 6% less than the predicted dose. The measurements on the esophagus averaged 25% less than predicted. These results provide an indication of the accuracy with which the treatment planning methods accounted for the motion of the target, with its respiratory and cardiac components. This is the first report on the accuracy of CyberKnife dose delivery to cardiac targets. PACS numbers: 87.53.Ly, 87.53.Bn
    Type of Medium: Online Resource
    ISSN: 1526-9914 , 1526-9914
    URL: Article
    DOI: 10.1120/jacmp.v13i3.3745
    Language: English
    Publisher: Wiley
    Publication Date: 2012
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  • 2
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    Stereotactic or conformal radiotherapy for adrenal metastases: Patient characteristics and outcomes in a multicenter analysis
    Wiley ; 2021
    In:  International Journal of Cancer Vol. 149, No. 2 ( 2021-07-15), p. 358-370
    Details
    In: International Journal of Cancer, Wiley, Vol. 149, No. 2 ( 2021-07-15), p. 358-370
    Abstract: What's new? When added to systemic therapy, does local treatment reduce recurrence or overall survival (OS) for patients with limited metastases? In this study, the authors found that, in patients with adrenal metastases, both stereotactic body radiotherapy (SBRT) and highly conformal, intensity‐modulated radiotherapy (3DCRT/IMRT) were associated with a decreased local recurrence rate and a mild toxicity profile. Local control at 12 months was, in turn, associated with increased OS.
    Type of Medium: Online Resource
    ISSN: 0020-7136 , 1097-0215
    URL: Issue
    URL: Article
    DOI: 10.1002/ijc.v149.2
    DOI: 10.1002/ijc.33546
    RVK:
    XA 10000
    Language: English
    Publisher: Wiley
    Publication Date: 2021
    detail.hit.zdb_id: 218257-9
    detail.hit.zdb_id: 1474822-8
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  • 3
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    Stereotactic body radiotherapy of adrenal metastases—A dose‐finding study
    Wiley ; 2022
    In:  International Journal of Cancer Vol. 151, No. 3 ( 2022-08), p. 412-421
    Details
    In: International Journal of Cancer, Wiley, Vol. 151, No. 3 ( 2022-08), p. 412-421
    Abstract: Optimal doses for the treatment of adrenal metastases with stereotactic radiotherapy (SBRT) are unknown. We aimed to identify dose‐volume cut‐points associated with decreased local recurrence rates (LRR). A multicenter database of patients with adrenal metastases of any histology treated with SBRT (biologically effective dose, BED10 ≥50 Gy, ≤12 fractions) was analyzed. Details on dose‐volume parameters were required (planning target volume: PTV‐D98%, PTV‐D50%, PTV‐D2%; gross tumor volume: GTV‐D50%, GTV‐mean). Cut‐points for LRR were optimized using the R maxstat package. One hundred and ninety‐six patients with 218 lesions were included, the largest histopathological subgroup was adenocarcinoma (n = 101). Cut‐point optimization resulted in significant cut‐points for PTV‐D50% (BED10: 73.2 Gy; P  = .003), GTV‐D50% (BED10: 74.2 Gy; P  = .006), GTV‐mean (BED10: 73.0 Gy; P  = .007), and PTV‐D2% (BED10: 78.0 Gy; P  = .02) but not for the PTV‐D98% ( P  = .06). Differences in LRR were clinically relevant (LRR ≥ doubled for cut‐points that were not achieved). Further dose‐escalation was not associated with further improved LRR. PTV‐D50%, GTV‐D50%, and GTV‐mean cut‐points were also associated with significantly improved LRR in the adenocarcinoma subgroup. Separate dose optimizations indicated a lower cut‐point for the PTV‐D50% (BED10: 69.1 Gy) in adenocarcinoma lesions, other values were similar ( 〈 2% difference). Associations of cut‐points with overall survival (OS) and progression‐free survival were not significant but durable freedom from local recurrence was associated with OS in a landmark model ( P   〈  .001). To achieve a significant improvement of LRR for adrenal SBRT, a moderate escalation of PTV‐D50% BED10  〉 73.2 Gy (adenocarcinoma: 69.1 Gy) should be considered.
    Type of Medium: Online Resource
    ISSN: 0020-7136 , 1097-0215
    URL: Issue
    URL: Article
    DOI: 10.1002/ijc.v151.3
    DOI: 10.1002/ijc.34017
    RVK:
    XA 10000
    Language: English
    Publisher: Wiley
    Publication Date: 2022
    detail.hit.zdb_id: 218257-9
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  • 4
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    Second infield re‐irradiation with a resulting cumulative equivalent dose (EQD2 max ) of 〉180 Gy for patients with recurrent head and neck cancer
    Wiley ; 2019
    In:  Head & Neck Vol. 41, No. 4 ( 2019-04)
    Details
    In: Head & Neck, Wiley, Vol. 41, No. 4 ( 2019-04)
    Abstract: For locally recurrent head and neck cancer, re‐irradiation with modern techniques like stereotactic body radiotherapy is a promising, possibly curative alternative to palliative systemic therapy. Methods We report on 1 patient with nasopharyngeal carcinoma (NPC) and 1 patient with cutaneous squamous cell carcinoma (SCC). Both patients received full dose primary treatment ( 〉 66 Gy, EQD2), full dose re‐irradiation ( 〉 50 Gy, EQD2), and a second course of re‐irradiation via robotic radiosurgery (CyberKnife) for a second local recurrence. Results Both treatments resulted in adequate tumor response. No grade III‐IV acute or late toxicities occurred. Follow‐up at 6 months after third irradiation showed partial remission for the patient with NPC. In the second case (SCC), no toxicities occurred and the tumor was in remission 18 months after last treatment. Conclusion These cases show that a second course of re‐irradiation utilizing modern techniques like robotic radiosurgery might be feasible for carefully selected patients with head and neck cancer.
    Type of Medium: Online Resource
    ISSN: 1043-3074 , 1097-0347
    URL: Issue
    URL: Article
    DOI: 10.1002/hed.v41.4
    DOI: 10.1002/hed.25428
    Language: English
    Publisher: Wiley
    Publication Date: 2019
    detail.hit.zdb_id: 2001440-5
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  • 5
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    Inverse treatment planning for spinal robotic radiosurgery: an international multi‐institutional benchmark trial
    Wiley ; 2016
    In:  Journal of Applied Clinical Medical Physics Vol. 17, No. 3 ( 2016-05), p. 313-330
    Details
    In: Journal of Applied Clinical Medical Physics, Wiley, Vol. 17, No. 3 ( 2016-05), p. 313-330
    Abstract: Stereotactic radiosurgery (SRS) is the accurate, conformal delivery of high‐dose radiation to well‐defined targets while minimizing normal structure doses via steep dose gradients. While inverse treatment planning (ITP) with computerized optimization algorithms are routine, many aspects of the planning process remain user‐dependent. We performed an international, multi‐institutional benchmark trial to study planning variability and to analyze preferable ITP practice for spinal robotic radiosurgery. 10 SRS treatment plans were generated for a complex‐shaped spinal metastasis with 21 Gy in 3 fractions and tight constraints for spinal cord ( , ) and target (coverage ). The resulting plans were rated on a scale from 1 to 4 (excellent‐poor) in five categories (constraint compliance, optimization goals, low‐dose regions, ITP complexity, and clinical acceptability) by a blinded review panel. Additionally, the plans were mathematically rated based on plan indices (critical structure and target doses, conformity, monitor units, normal tissue complication probability, and treatment time) and compared to the human rankings. The treatment plans and the reviewers' rankings varied substantially among the participating centers. The average mean overall rank was 2.4 (1.2‐4.0) and 8/10 plans were rated excellent in at least one category by at least one reviewer. The mathematical rankings agreed with the mean overall human rankings in 9/10 cases pointing toward the possibility for sole mathematical plan quality comparison. The final rankings revealed that a plan with a well‐balanced trade‐off among all planning objectives was preferred for treatment by most participants, reviewers, and the mathematical ranking system. Furthermore, this plan was generated with simple planning techniques. Our multi‐institutional planning study found wide variability in ITP approaches for spinal robotic radiosurgery. The participants', reviewers', and mathematical match on preferable treatment plans and ITP techniques indicate that agreement on treatment planning and plan quality can be reached for spinal robotic radiosurgery. PACS number(s): 87.55.de
    Type of Medium: Online Resource
    ISSN: 1526-9914 , 1526-9914
    URL: Article
    DOI: 10.1120/jacmp.v17i3.6151
    Language: English
    Publisher: Wiley
    Publication Date: 2016
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  • 6
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    Combining computed tomography and biologically effective dose in radiomics and deep learning improves prediction of tumor response to robotic lung stereotactic body radiation therapy
    Wiley ; 2021
    In:  Medical Physics Vol. 48, No. 10 ( 2021-10), p. 6257-6269
    Details
    In: Medical Physics, Wiley, Vol. 48, No. 10 ( 2021-10), p. 6257-6269
    Abstract: The aim of this study is to improve the performance of machine learning (ML) models in predicting response of non‐small cell lung cancer (NSCLC) to stereotactic body radiation therapy (SBRT) by integrating image features from pre‐treatment computed tomography (CT) with features from the biologically effective dose (BED) distribution. Materials and methods Image features, consisting of crafted radiomic features or machine‐learned features extracted using a convolutional neural network, were calculated from pre‐treatment CT data and from dose distributions converted into BED for 80 NSCLC lesions over 76 patients treated with robotic guided SBRT. ML models using different combinations of features were trained to predict complete or partial response according to response criteria in solid tumors, including radiomics CT (Rad CT ), radiomics CT and BED (Rad CT,BED ), deep learning (DL) CT (DL CT ), and DL CT and BED (DL CT,BED ). Training of ML included feature selection by neighborhood component analysis followed by ensemble ML using robust boosting. A model was considered as acceptable when the sum of average sensitivity and specificity on test data in repeated cross validations was at least 1.5. Results Complete or partial response occurred in 58 out of 80 lesions. The best models to predict the tumor response were those using BED variables, achieving significantly better area under curve (AUC) and accuracy than those using only features from CT, including a Rad CT,BED model using three radiomic features from BED, which scored an accuracy of 0.799 (95% confidence intervals (0.75–0.85)) and AUC of 0.773 (0.688–0.846), and a DL CT,BED model also using three variables with an accuracy of 0.798 (0.649–0.829) and AUC of 0.812 (0.755–0.867). Conclusion According to our results, the inclusion of BED features improves the response prediction of ML models for lung cancer patients undergoing SBRT, regardless of the use of radiomic or DL features.
    Type of Medium: Online Resource
    ISSN: 0094-2405 , 2473-4209
    URL: Issue
    URL: Article
    DOI: 10.1002/mp.v48.10
    DOI: 10.1002/mp.15178
    Language: English
    Publisher: Wiley
    Publication Date: 2021
    detail.hit.zdb_id: 1466421-5
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  • 7
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    Stereotactic radiosurgery and radiotherapy for brainstem metastases: An international multicenter analysis
    Wiley ; 2024
    In:  International Journal of Cancer
    Details
    In: International Journal of Cancer, Wiley
    Abstract: Brainstem metastases (BSM) present a significant neuro‐oncological challenge, resulting in profound neurological deficits and poor survival outcomes. Stereotactic radiosurgery (SRS) and fractionated stereotactic radiotherapy (FSRT) offer promising therapeutic avenues for BSM despite their precarious location. This international multicenter study investigates the efficacy and safety of SRS and FSRT in 136 patients with 144 BSM treated at nine institutions from 2005 to 2022. The median radiographic and clinical follow‐up periods were 6.8 and 9.4 months, respectively. Predominantly, patients with BSM were managed with SRS (69.4%). The median prescription dose and isodose line for SRS were 18 Gy and 65%, respectively, while for FSRT, the median prescription dose was 21 Gy with a median isodose line of 70%. The 12‐, 24‐, and 36‐month local control (LC) rates were 82.9%, 71.4%, and 61.2%, respectively. Corresponding overall survival rates at these time points were 61.1%, 34.7%, and 19.3%. In the multivariable Cox regression analysis for LC, only the minimum biologically effective dose was significantly associated with LC, favoring higher doses for improved control (in Gy, hazard ratio [HR]: 0.86, p 〈 .01). Regarding overall survival, good performance status (Karnofsky performance status, ≥90%; HR: 0.43, p 〈 .01) and prior whole brain radiotherapy (HR: 2.52, p 〈 .01) emerged as associated factors. In 14 BSM (9.7%), treatment‐related adverse events were noted, with a total of five (3.4%) radiation necrosis. SRS and FSRT for BSM exhibit efficacy and safety, making them suitable treatment options for affected patients.
    Type of Medium: Online Resource
    ISSN: 0020-7136 , 1097-0215
    URL: Article
    DOI: 10.1002/ijc.34980
    RVK:
    XA 10000
    Language: English
    Publisher: Wiley
    Publication Date: 2024
    detail.hit.zdb_id: 218257-9
    detail.hit.zdb_id: 1474822-8
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  • 8
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    A retrospective multi‐center feasibility study of a new PTV margin estimation approach for moving targets using CyberKnife log files
    Wiley ; 2023
    In:  Journal of Applied Clinical Medical Physics Vol. 24, No. 7 ( 2023-07)
    Details
    In: Journal of Applied Clinical Medical Physics, Wiley, Vol. 24, No. 7 ( 2023-07)
    Abstract: This study investigates a new approach for estimating the planning target volume (PTV) margin for moving tumors treated with robotic stereotactic body radiotherapy (SBRT). Methods In this new approach, the covariance of modeling and prediction errors was estimated using error propagation and implemented in the Van Herk formula to form a Modified Van Herk formula (MVHF). To perform a retrospective multi‐center analysis, the MVHF was studied using 163 patients treated with different system versions of robotic SBRT (G3 version 6.2.3, VSI version 8.5, and VSI version 9.5) and compared with two established PTV margins estimation methods: The original Van Herk Formula (VHF) and the Uncertainty Estimation Method (UEM). Results Overall, the PTV margins provided by the three formalisms are similar with 4–5 mm in the lung region and 4 mm in abdomen region to the PTV margins used in clinical. Furthermore, when analyzing individual patients, a difference of up to 1 mm was found between the PTV margin estimations using MVHF and VHF. The corresponding average discrepancies for the superior‐inferior (SI) direction ranged between −0.19 mm to 0.38 mm in CK G3 version 6.2.3, −0.36 mm to 0.33 mm in CK VSI version 8.5, and −0.34 mm to 0.40 mm in CK VSI version 9.5. Conclusions It was found that for the lower left lung, upper left lung, lower right lung, upper right lung, central liver, and upper liver, the effect of covariance between model and prediction errors in SI direction was around 20%, 30%, 25%, 25%, 25%, and 30%, respectively. Notable covariance effects between model and prediction errors can be considered in PTV margin estimation using a modified VHF, which allowed for more precise target localization in robotic SBRT for moving tumors. Overall, in each of the three directions, the difference between MVHF and utilized clinical margins is 0.65 mm in the lung and abdominal region. Therefore, to improve the clinical PTV margins with the new approach, it is suggested to use the adaptive PTV margins in the next fractions.
    Type of Medium: Online Resource
    ISSN: 1526-9914 , 1526-9914
    URL: Issue
    URL: Article
    DOI: 10.1002/acm2.v24.7
    DOI: 10.1002/acm2.13975
    Language: English
    Publisher: Wiley
    Publication Date: 2023
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  • 9
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    Stereotactic radiotherapy combined with immunotherapy or targeted therapy for metastatic renal cell carcinoma
    Wiley ; 2021
    In:  BJU International Vol. 127, No. 6 ( 2021-06), p. 703-711
    Details
    In: BJU International, Wiley, Vol. 127, No. 6 ( 2021-06), p. 703-711
    Abstract: To evaluate the safety and efficacy of stereotactic radiotherapy (SRT) in patients with metastatic renal cell carcinoma (mRCC) concurrently receiving targeted therapy (TT) or immunotherapy. Patients and Methods Data on patients with mRCC were extracted from a retrospective international multicentre register study (TOaSTT), investigating SRT concurrent (≤30 days) with TT/immune checkpoint inhibitor (ICI) therapy. Overall survival (OS), progression‐free survival (PFS), local metastasis control (LC) and time to systemic therapy switch were analysed using Kaplan–Meier curves and log‐rank testing. Clinical and treatment factors influencing survival were analysed using multivariate Cox regression. Acute and late SRT‐induced toxicity were defined according to the Common Terminology Criteria for Adverse Events v.4.03. Results Fifty‐three patients who underwent 128 sessions of SRT were included, of whom 58% presented with oligometastatic disease (OMD). ICIs and TT were received by 32% and 68% of patients, respectively. Twenty patients (37%) paused TT for a median (range) of 14 (2–21) days. ICI therapy was not paused in any patient. A median (range) of 1 (1–5) metastatic tumour was treated per patient, with a median (range) SRT dose of 65 (40–129.4) Gy (biologically effective dose). The OS, LC and PFS rates at 1 year were 71%, 75% and 25%, respectively. The median OS and PFS were not significantly different among patients receiving TT vs those receiving ICIs ( P = 0.329). New lesions were treated with a repeat radiotherapy course in 46% of patients. After 1 year, 62% of patients remained on the same systemic therapy as at the time of SRT; this was more frequent for ICI therapy compared to TT (83% vs 36%; P = 0.035). OMD was an independent prognostic factor for OS ( P = 0.004, 95% confidence interval [CI] 0.035–0.528) and PFS ( P = 0.004; 95% CI 0.165–0.717) in multivariate analysis. Eastern Cooperative Oncology Group performance status (ECOG‐PS) was the other independent prognostic factor for OS ( P = 0.001, 95% CI 0.001–0.351). Acute grade 3 toxicity was observed in two patients, and late grade 3 toxicity in one patient. No grade 4 or 5 toxicity was observed. Conclusion Combined treatment with TT or immunotherapy and concurrent SRT was safe, without signals of increased severe toxicity. As we observed no signal of excess toxicity, full‐dose SRT should be considered to achieve optimal metastasis control in patients receiving TT or immunotherapy. Favourable PFS and OS were observed for patients with oligometastatic RCC with a good ECOG‐PS, which should form the basis for prospective testing of this treatment strategy in properly designed clinical trials.
    Type of Medium: Online Resource
    ISSN: 1464-4096 , 1464-410X
    URL: Issue
    URL: Article
    DOI: 10.1111/bju.v127.6
    DOI: 10.1111/bju.15284
    Language: English
    Publisher: Wiley
    Publication Date: 2021
    detail.hit.zdb_id: 2019983-1
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