ABSTRACT
Objective:To introduce the stereotactic cardiac radioablation (SCRA) based on the stereotactic body radiotherapy (SBRT), and comprehensively evaluate the new approach by short-term effectiveness and safety.Methods:Patients with ventricular arrhythmia (VA) were evaluated and included in this clinical trial, who were immobilized by vacuum bag and performed simulation with 4-dimensional computed tomography (4DCT). In this study, the planning target volume (PTV) was set as the target to design a SBRT plan using volumetric modulated arc therapy (VMAT), which was evaluated by dose parameters such as R 50%, homogeneity index and conformity index, etc. The results of Holter and echocardiography were monitored during the follow-up and compared with the data before treatment. Results:Three subjects with ventricular tachycardia (VT) and one with premature ventricular contraction (PVC) received the same prescription of 25 Gy in a single fraction. The average volume of PTV was 71.4 cm 3(60.3-89.4 cm 3). The average time of beam delivery was 12.0 min (4.5-21.0 min). And the short-term follow-up lasted for an average of 18 weeks (14-25 weeks), which showed significant decrease in both VT and PVC load without complications. Conclusion:This study reports the implementation method of SCRA and proves its short-term effectiveness and safety, but the effects and standards of the key radiotherapy techniques still need to be explored.
ABSTRACT
Prolonged instances of arrhythmia may not only exacerbate original heart diseases,but also cause hemodynamic disorders and even sudden death.Catheter ablation,which utilizes a catheter to directly destroy the underlying arrhythmia substrate,has become the main treatment.Recent advances have enabled noninvasive delivery of precise arrhythmia radioablation with electrophysiology-guided stereotactic body radiation therapy(SBRT),termed stereotactic arrhythmia radioablation(STAR).The progress of STAR was reviewed in this paper.
ABSTRACT
PURPOSE: Postoperative thyroid remnant radioablation therapy is necessary to reduce the recurrence and mortality rates as well as to prepare the patients for a proper long term surveillance of well-differentiated thyroid cancers. The radiation safety rules of the government require the patient to be isolated in a hospital if the expected radiation exposure to the family members would be greater than 5 mSv (500 mRem). The purpose was to measure the radiation received by the family members of patients who received large doses of NaI-131. MATERIAL AND METHODS: We have administered 12 therapy doses ranging from 3.70-5.55 GBq (100 to 150 mCi) to 11 patients, and released them immediately if they met the radiation safety criteria. Informed consent was obtained from the subjects prior to the therapy, and each of them agreed to follow written radiation safety instructions. TLD badges were used to measure the radiation dose received by the family members and the room adjacent to the patient's bed room during the first 72 hours. RESULTS: The average dose received by the family members who spent the most time in the closest distance with the patients was 0.04 mSv with a range of 0.01-0.17 mSv. Even the highest dose was only about 3% of the limit set by the government. The average radiation dose to the outer wall of the patient's room was 0.15 mSv. CONCLUSION: It is concluded that I-131 ablation therapy can be administered to outpatients safely to thyroid cancer patients who meet the established radiation safety criteria and follow the instructions.