Inadvertent hypothermia in paediatric radiotherapy practices under sedation: a single centre observational study.

OBJECTIVE: To detect changes in body temperature during outpatient procedures and to identify factors associated with hypothermia in the paediatric population undergoing radiotherapy under sedation. METHODS: The observational study was conducted between July and October 2022 at Ankara City Hospital, Turkey, and comprised paediatric cancer patients aged from 1 month to 18 years who needed sedation or general anaesthesia during radiotherapy. Baseline body temperature T1 was measured before transportation to the radiotherapy room, while body temperature T2 was taken after radiotherapy. Data was analysed using SPSS 20. RESULTS: A total of 152 radiotherapy sessions related to 13 children were evaluated. There were 8(61%) boys and 5(38%) girls with overall mean 4.46±3.45 years (range: 2-13 years). The mean body surface area as 0.70±0.212. Radiotherapy was performed in 9(69%) patients, while 4(31%) patients underwent tomotheraphy. The dose used was 180cGy in 12(92.3%) patients. Hypothermia was observed in at least one session in 12(92.3%) patients. There was significant difference in body temperature at baseline and post-radiotherapy (p<0.05). CONCLUSIONS: There were significant changes in body temperature during outpatient procedures in the paediatric population undergoing radiotherapy under sedation.

From organ at risk to target organ: Dosimetric comparison of myocardial stereotactic ablative body radiotherapy between helical tomotherapy and volumetric arc therapy for refractory ventricular tachycardia.

Ventricular tachycardia (VT) is an important type of arrhythmia with a risk of sudden death. Although implanted cardiac defibrillation and radiofrequency ablation are used together with medical treatments for VT, the treatment options are limited in cases that do not respond to them. Stereotactic ablative body radiotherapy (SABR) applied to VT substrates in resistant cases is an emerging treatment with positive results. Such clinical results have increased the interest in this subject. However, the ideal treatment device and method have not yet been described for this therapy, which is generally applied at a single fraction using various devices and methods. Herein, treatment planning was conducted for a total of 8 patients (11 VT substrates) using the Varian TrueBeam EDGE and TomoTherapy Radixact devices at a single center, and the results were compared dosimetrically. The Wilcoxon-signed rank test was used for the statistical analysis, and mean values were expressed as medians and interquartile ranges (IQRs). In the volumetric modulated arc therapy (VMAT) and helical tomotherapy (HT) plans, the plan coverages and conformity indexes were similar; meanwhile, the homogeneity indexes were 0.10 (IQR = 0.05) and 0.07 (IQR = 0.05), respectively, and were significantly better in the HT plan (p = 0.02). The gradient indexes were 3.18 (IQR = 0.8) and 5.33 (IQR = 3.68) in the VMAT and HT plans, respectively, and were significantly better in the VMAT plan. For the organs at risk, similar doses were observed. The maximum doses for the stomach and esophagus and the mean doses for the left lung and both lungs were significantly lower in the VMAT plan. Similarly, the maximum and mean doses for the cardiac substructures and great vessels were significantly lower in the VMAT plan. More homogeneous plans were obtained in HT, while a faster dose reduction and lower critical organ dose were observed in VMAT. Reasonable myocardial SABR plans could be obtained with both techniques. The effects of the dosimetric differences on the clinical outcomes should be evaluated in prospective clinical studies.

Stereotactic body radioablation therapy as an immediate and early term antiarrhythmic palliative therapeutic choice in patients with refractory ventricular tachycardia.

BACKGROUND: Stereotactic body radioablation therapy (SBRT) has recently been introduced with the ability to provide ablative energy noninvasively to arrhythmogenic substrate while reducing damage to normal cardiac tissue nearby and minimizing patients' procedural risk. There is still debate regarding whether SBRT has a predominant effect in the early or late period after the procedure. We sought to assess the time course of SBRT's efficacy as well as the value of using a blanking period following a SBRT session. METHODS: Eight patients (mean age 58 ± 14 years) underwent eight SBRT sessions for refractory ventricular tachycardia (VT). SBRT was given using a linear accelerator device with a total dose of 25 Gy to the targeted area. RESULTS: During a median follow-up of 8 months, all patients demonstrated VT recurrences; however, implantable cardioverter-defibrillator (ICD) and anti-tachycardia pacing therapies were significantly reduced with SBRT (8.46 to 0.83/per month, p = 0.047; 18.50 to 3.29/per month, p = 0.036, respectively). While analyzing the temporal SBRT outcomes, the 2 weeks to 3 months period demonstrated the most favorable outcomes. After 6 months, one patient was ICD therapy-free and the remaining patients demonstrated VT episodes. CONCLUSIONS: Our findings showed that the SBRT was associated with a marked reduction in the burden of VT and ICD interventions especially during first 3 months. Although SBRT does not seem to succeed complete termination of VT in long-term period, our findings support the strategy that SBRT can be utilized for immediate antiarrhythmic palliation in critically ill patients with otherwise untreatable refractory VT and electrical storm.

Helical tomotherapy experience in breast cancer adjuvant radiotherapy and acute toxicity results.

Background: This study aimed to evaluate acute toxicity and oncological outcomes of breast cancer patients who underwent adjuvant radiotherapy (RT) with tomotherapy. Materials and methods: The results of 114 patients who underwent adjuvant RT with Tomotherapy device between 17.08.10-12.06.2021 in Ankara Atatürk Training and Research Hospital and Ankara City Hospital were evaluated retrospectively. The primary endpoint of the study was acute adverse events, and the secondary endpoints were overall survival (OS) and disease-free survival (DFS). Results: The results of 103 patients who met the inclusion criteria were analyzed. The median follow-up was 21 (range 1-125.8) months. Grade +3 esophagitis was not observed in any patient; no esophagitis was observed in 60 (58.3%) patients. Grade 3 dermatitis was observed in 3 (2.9%) patients. In addition, dermatitis was not observed in 47 (45.6%) patients. The relationship between chest wall volume and esophagitis development was statistically significant (p = 0.006; Z score: -2769). The median OS was 24.1 (range 1-128.5) and median disease-free survival was 21.1 (range 1-125.8) months. Five patients (4.9%) died and 9 patients (8.7%) relapsed. Local recurrence was observed in only 1 (1%) patient. There was a statistically significant correlation between OS and contralateral lung V20 dose [p < 0.001; Spearman Correlation Coefficient (SCC) -406) and heart mean dose (p < 0.001; SCC -370)]. There was a statically significant correlation between DFS and cN (p < 0.001); pN (p < 0.001); heart mean dose (p < 0.001; SCC -351); contralateral lung V5 dose (p = 0.041; SCC -213); contralateral lung V20 dose (p < 0.001; SCC -434). Conclusion: Acute toxicity results show improvement in breast cancer adjuvant radiotherapy with helical tomotherapy.

Use of Stereotactic Radioablation Therapy as a Bailout Therapy for Refractory Ventricular Tachycardia in a Patient with a No-entry Left Ventricle.

In patients with mechanical aortic and mitral valves and left ventricular (LV) tachycardia (VT), catheter ablation is technically challenging due to the limited access to the LV. Promising new alternatives to radiofrequency ablation include pulsed-field electroporation, percutaneous or surgical sympathetic neuromodulation, and noninvasive stereotactic radioablation therapy (SBRT). We herein describe the effect of SBRT as a bailout therapy on the management of a challenging VT case in the presence of double left-sided mechanical valves.