BACKGROUND: Ventricular tachycardia is an irregular heartbeat conventionally treated using invasive cardiac catheter ablation and medication. However, when standard treatments have been exhausted, cardiac SABR provides a final treatment option to this high-mortality condition. Complex diagnostic mapping and planning scans enable multi-disciplinary target delineation for a 25Gy single fraction. However, organs at risk (OAR) near the target make this treatment challenging to plan and deliver. Publications from cardiologists report the efficacy of cardiac SABR, however there is limited data on the treatment delivery and image matching of this complex procedure.
METHODS: Four specialist therapeutic radiographers experienced in cardiac SABR reviewed 40 CBCTs from 10 patients treated in the UK. Each therapeutic radiographer conducted five image matches: a manual match (manual), an automatic match to the heart structure (auto) and the auto match followed by manual adjustment to the PTV (PTV), all using three degrees of freedom (DoF) only. The auto and PTV matches were also repeated using 6DoF. Inter-observer variability was quantified using 95% limits of agreement from a modified Bland-Altman analysis.
RESULTS: The limits of agreement were smallest in the automatic matches suggesting the algorithm is reliable. A manual adjustment from the auto match to the PTV is clinically appropriate to optimise target coverage. The limits of agreement were smaller in the 6DoF PTV match 1.06 mm, 1.24 mm, 1.68 mm than the 3DoF PTV match 1.57 mm, 2.06 mm, 2.11 mm (lateral, vertical, longitudinal).
CONCLUSIONS: The 6DoF CBCT image match has less variability and therefore suggest using a 6DoF couch for treatment delivery.
CONCLUSIONS: Cardiac SABR CBCT image matching at treatment delivery is complex, optimisation of CBCT acquisition parameters and therapeutic radiographer training is essential prior to implementation.

BACKGROUND: Differences in radiation-induced lymphopenia and prognosis between methods of radiotherapy (RT) for brain metastases remain unclear.
METHODS: In this retrospective analysis of patients who underwent whole-brain radiotherapy (WBRT) or stereotactic radiosurgery/radiotherapy (SRS/SRT) for brain metastases, baseline total lymphocyte count (TLC) data were obtained within 2 weeks before RT initiation. Follow-up TLC data were evaluated at 0-2, 2-4, and 4-8 weeks after RT completion. Persistent lymphopenia was defined as <800/μL at any time point.
RESULTS: Overall, 138 RT courses in 128 patients were eligible (94 WBRT; 44 SRS/SRT). In the WBRT courses, the median baseline TLC was 1325/μL (IQR: 923-1799). Follow-up TLC decreased significantly to 946/μL (626-1316), 992/μL (675-1291), and 1075/μL (762-1435) (p < 0.001). SRS/SRT courses showed no significant TLC decrease. Multivariate analysis revealed female sex, prior RT, baseline TLC < 800/μL, and WBRT use were significantly associated with persistent lymphopenia. In the WBRT group, overall survival was significantly different between those with and without persistent lymphopenia (median, 2.6 and 6.1 months; p < 0.001). However, there was no significant difference in survival in the SRS/SRT group (p = 0.60).
CONCLUSIONS: This study suggests SRS/SRT might be preferable for lymphocyte preservation in brain metastasis patients.

The combination of immune checkpoint inhibitors (ICIs) and radiotherapy has shown promise in the treatment of metastatic non-small cell lung cancer (NSCLC). The present meta-analysis aimed to determine the efficacy and safety of combining radiotherapy (RT) ICIs for the treatment of metastatic NSCLC. PubMed, Google Scholar, the Cochrane Library and Web of Science databases were searched for relevant articles up to February 1, 2023. Post-therapy outcomes such as progression-free survival (PFS), complete response, partial response (PR), progressive disease (PD), stable disease and adverse events (AEs) were analyzed. The meta-analysis was performed using RevMan 5.4 software. A total of seven studies involving 682 patients were included (384 patients who received ICI + RT vs. RT and 298 patients who received ICI + RT vs. ICI alone). No significant difference in PFS was demonstrated between the ICI + RT group and the RT group (heterogeneity: χ2=2.35; df=1; P=0.13; I2=57% and test for overall effect: Z=0.10; P=0.92). Conversely, patients in the ICI alone group had significantly decreased PR rates (heterogeneity: Τ2=0.00; χ2=2.13; df=3; P=0.54; I2=0% and test for overall effect: Z=2.57; P=0.01) compared with patients in the ICI + RT group. The ICI + RT group also had significantly lower rates of PD (heterogeneity: Τ2=0.00; χ2=0.91; df=3; P=0.82; I2=0% and test for overall effect: Z=2.52; P=0.01) compared with the ICI alone group. Safety analysis revealed no significant difference between patients who received ICI + RT and those who received RT in terms of grade 1 or 2 AEs. In conclusion, the combination of ICIs + RT demonstrates promising efficacy and safety for patients with metastatic NSCLC. However, clinical trials that have tested this combination are lacking, which emphasizes the need for further research.

UNASSIGNED: non-small cell lung cancer (NSCLC) accounts for more than 80% of all lung cancer populations. Stereotactic radiotherapy (SBRT) is mainly suitable for early NSCLC patients who are not suitable for surgery or refuse surgery.
UNASSIGNED: To analyze the effects of stereotactic radiotherapy (SBRT) plus immunotherapy for non-small cell lung cancer (NSCLC) patients on their immune status and survival quality.
UNASSIGNED: NSCLC patients admitted to our hospital from 2019-2022 were divided into 61 cases in control group (SBRT) and 60 cases in observation group (SBRT plus immunotherapy) by the randomized numerical table method to compare the efficacy, the level of tumor markers in the serum, the level and activity of the immune cells in the peripheral blood and the Kahlil\'s functional status (KPS) scores.
UNASSIGNED: The observation group had a higher efficacy rate than that of the control group (P< 0.05). There was no statistical difference between the two groups in serum tumor marker content, immune cell level and activity in peripheral blood and KPS score before treatment (P> 0.05). After treatment, serum tumor markers were lower than those in control group, and immune cell level, NK cell-related activity and KPS score were higher than those in control group (P< 0.05).
UNASSIGNED: SBRT plus immunotherapy can reduce the level of various tumor markers, improve the immune status and quality of survival for NSCLC patients.

Intramedullary metastases (IMM) lead to severe neurological symptoms. They are extremely rare in clinical practice. Optimal management of such patients is not clearly defined. Surgery, chemo- and radiotherapy are the main options.
OBJECTIVE: To study the results of stereotactic high-dose irradiation for IMM considering local control of metastases, neurological status and life expectancy.
METHODS: Nineteen patients with 29 IMMs underwent high-dose irradiation (Cyber Knife G4 and TrueBeam STx devices) between 2016 and 2022. There were 1-10 fractions, radiation dose 14.0-35.0 Gy with isodose 70-100%. Local control and new spinal cord metastases were assessed using contrast-enhanced MRI. Clinical status and neurological functions were assessed using the Karnofsky and McCormick scales.
RESULTS: Local control rates were 91% and 78% after 6 and 12 months, respectively. Overall survival after treatment was 7.3 months, 6- and 12-month overall survival - 58% and 37%, respectively. In addition, 8 patients were available for follow-up. Of these, 6 ones demonstrated improvement or stabilization of neurological function after treatment. The main cause of death was progression of the underlying disease. No significant treatment-related toxic effects were observed.
CONCLUSIONS: High-dose irradiation is a safe, effective and time-saving treatment for IMM. Considering unadvisable surgical methods and chemotherapy for this pathology, we can recommend high-dose irradiation for patients with spinal cord metastases.
Интрамедуллярные метастазы (ИММ) приводят к выраженной неврологической симптоматике. В практике клинициста они встречаются крайне редко. Оптимальные алгоритмы ведения таких пациентов четко не определены. Основными методами лечения служат хирургическое вмешательство, химиотерапия и лучевая терапия.
UNASSIGNED: Изучить результаты лечения ИММ методом стереотаксического высокодозного облучения (СВО) с анализом локального контроля метастазов, неврологического статуса и продолжительности жизни пациентов.
UNASSIGNED: С 2016 по 2022 г. в нейрорадиологическом отделении лучевой терапии Медицинского института им. Сергея Березина пролечены 19 пациентов с 29 ИММ методом СВО на аппаратах CyberKnife G4 и TrueBeam STx. Проведено от 1 до 10 фракций, доза облучения составила от 14,0 до 35,0 Гр, предписанная по изодозе от 70 до 100%. Локальный контроль, появление новых метастазов в спинном мозге оценивались по данным контрольной магнитно-резонансной томограммы с контрастным усилением. Оценка состояния пациентов и неврологических функций была выполнена с помощью шкал Карновского и McCormick.
UNASSIGNED: Показатели локального контроля через 6 и 12 мес составили 91 и 78% соответственно. Медиана общей выживаемости (ОВ) после лечения составила 7,3 мес, а 6- и 12-месячная ОВ — 58 и 37%. Кроме того, под доступным клиническим наблюдением было 8 пациентов, 6 из которых продемонстрировали улучшение или стабилизацию неврологических функций после лечения. Ведущей причиной смерти было прогрессирование основного заболевания. Значительных токсических эффектов, связанных с лечением, не наблюдалось.
UNASSIGNED: СВО является безопасным, эффективным и экономным по времени методом лечения ИММ. Учитывая ограниченные возможности применения хирургических методов и химиотерапии при данной патологии, его можно рассматривать в качестве выбора у пациентов с метастазами в спинной мозг.

OBJECTIVE: 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.
METHODS: 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 BED10Gy (BED10Gy95% and BED10Gy90%) and to RC + 0 to + 5 mm expansion margins, and parameters associated with radiation necrosis risk (V83Gy, V103Gy, V123Gy and V243Gy) to the normal brain were evaluated by a Wilcoxon-signed rank test.
RESULTS: For RC + 0 mm, median BED10Gy 90% for STaRT (90.1 Gy10, range: 64.1-140.9 Gy10) was significantly higher than CK (74.3 Gy10, range:59.3-80.4 Gy10, p = 0.04), GK (69.4 Gy10, range: 59.8-77.1 Gy10, p = 0.005), and IMPT (49.3 Gy10, range: 49.0-49.7 Gy10, p = 0.003), respectively. However, for the RC + 5 mm, the median BED10Gy 90% for STaRT (34.1 Gy10, range: 22.2-59.7 Gy10) was significantly lower than CK (44.3 Gy10, range: 37.8-52.4 Gy10), and IMPT (46.6 Gy10, range: 45.1-48.5 Gy10), respectively, but not significantly different from GK (34.1 Gy10, range: 22.8-47.0 Gy10). The median V243Gy 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).
CONCLUSIONS: 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.

OBJECTIVE: Stereotactic ablative body radiotherapy (SABR) is increasingly used for early-stage lung cancer, however the impact of dose to the heart and cardiac substructures remains largely unknown. The study investigated doses received by cardiac substructures in SABR patients and impact on survival.
METHODS: SSBROC is an Australian multi-centre phase II prospective study of SABR for stage I non-small cell lung cancer. Patients were treated between 2013 and 2019 across 9 centres. In this secondary analysis of the dataset, a previously published and locally developed open-source hybrid deep learning cardiac substructure automatic segmentation tool was deployed on the planning CTs of 117 trial patients. Physical doses to 18 cardiac structures and EQD2 converted doses (α/β = 3) were calculated. Endpoints evaluated include pericardial effusion and overall survival. Associations between cardiac doses and survival were analysed with the Kaplan-Meier method and Cox proportional hazards models.
RESULTS: Cardiac structures that received the highest physical mean doses were superior vena cava (22.5 Gy) and sinoatrial node (18.3 Gy). The highest physical maximum dose was received by the heart (51.7 Gy) and right atrium (45.3 Gy). Three patients developed grade 2, and one grade 3 pericardial effusion. The cohort receiving higher than median mean heart dose (MHD) had poorer survival compared to those who received below median MHD (p = 0.00004). On multivariable Cox analysis, male gender and maximum dose to ascending aorta were significant for worse survival.
CONCLUSIONS: Patients treated with lung SABR may receive high doses to cardiac substructures. Dichotomising the patients according to median mean heart dose showed a clear difference in survival. On multivariable analyses gender and dose to ascending aorta were significant for survival, however cardiac substructure dosimetry and outcomes should be further explored in larger studies.

Juntendo University Hospital is the second hospital in Japan to start stereotactic brain irradiation using linear accelerator (LINAC) system. This report details the historical transition of stereotactic irradiation, progress of treatment technology, and change of treatment method from the beginning to the Juntendo University Hospital and Juntendo Nerima Hospital. The hospital changed the use of cobalt to the LINAC system when it was rebuilt in 1993. Total body irradiation treatment for leukemia had started around the same time. A year later, in 1994, the hospital used their LINAC systems to perform stereotactic head irradiation, otherwise known as pinpoint irradiation. In 2005, Juntendo University Nerima Hospital was opened and in September of the same year, radiation therapy using the latest model of LINAC system at that time was initiated. This was the first among all Juntendo hospitals to start intensity-modulated radiation therapy (IMRT) and image-guided radiotherapy (IGRT). In 2014, a second LINAC system for IMRT and IGRT was equipped at the Juntendo Hongo Hospital. In 2021, the LINAC systems of the Juntendo University Nerima Hospital were replaced after 15 years of usage. The new method of SRS was started using a latest LINAC systems. In this paper, I introduce the technique and progress of SRS that I have experienced mainly in Juntendo University.

UNASSIGNED: The aim of our study was to compare dosimetric aspects of three radioablation modalities - direct high-dose-rate brachytherapy (HDR-BT) and virtually planned stereotactic body radiation therapy performed on CyberKnife (SBRTck) and Elekta Versa HD LINAC (SBRTe) applied in patients with liver metastases.
UNASSIGNED: We selected 30 patients with liver metastases, who received liver interstitial HDR-BT and virtually prepared plans for SBRTck and SBRTe. In all the cases, the prescribed dose was a single fraction of 25 Gy. Treatment delivery time, doses delivered to PTV and organs at risk, as well as conformity indices, were calculated and compared.
UNASSIGNED: The longest median treatment delivery time was observed in SBRTck in contrast to HDR-BT and SBRTe which were significantly shorter and comparable. HDR-BT plans achieved better coverage of PTV (except for D98%) in contrast to SBRT modalities. Between both SBRT modalities, SBRTck plans resulted in better dose coverage in Dmean, D50%, and D90% values compared to SBRTe without difference in D98%. The SBRTe was the most advantageous considering the PCI and R100%. SBRTck plans achieved the best HI, while R50% value was comparable between SBRTe and SBRTck. The lowest median doses delivered to uninvolved liver volume (V5Gy, V9.1Gy) were achieved with HDR-BT, while the difference between SBRT modalities was insignificant. SBRT plans were better regarding more favourable dose distribution in the duodenum and right kidney, while HDR-BT achieved lower doses in the stomach, heart, great vessels, ribs, skin and spinal cord. There were no significant differences in bowel and biliary tract dose distribution between all selected modalities.
UNASSIGNED: HDR-BT resulted in more favourable dose distribution within PTVs and lower doses in organs at risk, which suggests that this treatment modality could be regarded as an alternative to other local ablative therapies in carefully selected patients\' with liver malignancies. Future studies should further address the issue of comparing treatment modalities in different liver locations and clinical scenarios.

BACKGROUND: Stereotactic body radiotherapy (SBRT) has firmly established its role in stage I NSCLC. Clinical trial results may not fully apply to real-world scenarios. This study aimed to uncover the real-world incidence of acute toxicity and 90-day mortality in patients with SBRT-treated stage I NSCLC and develop prediction models for these outcomes.
METHODS: Prospective data from the Dutch Lung Cancer Audit for Radiotherapy (DLCA-R) were collected nationally. Patients with stage I NSCLC (cT1-2aN0M0) treated with SBRT in 2017 to 2021 were included. Acute toxicity was assessed, defined as grade greater than or equal to 2 radiation pneumonitis or grade greater than or equal to 3 non-hematologic toxicity less than or equal to 90 days after SBRT. Prediction models for acute toxicity and 90-day mortality were developed and internally validated.
RESULTS: Among 7279 patients, the mean age was 72.5 years, with 21.6% being above 80 years. Most were male (50.7%), had WHO scores 0 to 1 (73.3%), and had cT1a-b tumors (64.6%), predominantly in the upper lobes (65.2%). Acute toxicity was observed in 280 (3.8%) of patients and 90-day mortality in 122 (1.7%). Predictors for acute toxicity included WHO greater than or equal to 2, lower forced expiratory volume in 1 second and diffusion capacity for carbon monoxide, no pathology confirmation, middle or lower lobe tumor location, cT1c-cT2a stage, and higher mean lung dose (c-statistic 0.68). Male sex, WHO greater than or equal to 2, and acute toxicity predicted higher 90-day mortality (c-statistic 0.73).
CONCLUSIONS: This nationwide study revealed a low rate of acute toxicity and an acceptable 90-day mortality rate in patients with SBRT-treated stage I NSCLC. Notably, advanced age did not increase acute toxicity or mortality risk. Our predictive models, with satisfactory performance, offer valuable tools for identifying high-risk patients.