Technical Note: Gold Marker Implants and High-Frequency Jet Ventilation for Stereotactic, Single-Dose Irradiation of Liver Tumors

Abstract

With reference to radiosurgery of the liver, we describe techniques designed to solve the methodological problem of striking targets subject to respiratory motion with the necessary precision. Implanting a gold marker in the vicinity of the liver tumor was the first step in ensuring the reproducibility of the isocenter's position. An 18-karat gold rod measuring 1.9 × 3 mm was implanted approximately 2 cm from the edge of the tumor as this was displayed in the spiral, thin-slice CT with contrast media. Both the implantation of the marker and the required, CT-controlled biopsy of the liver tumor can be achieved simultaneously with the same puncture needle. The efficiency of high-frequency jet ventilation (HFJV) in neutralizing the targeted organ's respiratory motion during stereotactic single-dose irradiation was evaluated. The procedure was carried out on ten patients without any complications. In the time between treatment planning and irradiation (3 days), no significant marker migration was observable. In all cases, the gold marker (volume: 7.5 mm³) was readily observable in the treatment beam using portal imaging. HFJV provided reliable immobilization. The liver motion in each anesthetized patient was limited to under 3.0 mm in all directions. Thus, the correct field settings and target reproducibility were able to be analyzed and documented during the irradiation. The combination of marker and HFJV enables the determination of stereotactic coordinates directly related to the liver itself and, in this way, stereotactic radiation treatment of liver tumors is freed from the uncertainties involved in orientation to bony landmarks, in respiratory motion, and in changes of position in the stereotactic body frame. The method is feasible and can improve the accuracy of stereotactic body radiation therapy.

High-Frequency Jet Ventilation for Complete Target Immobilization and Reduction of Planning Target Volume in Stereotactic High Single-Dose Irradiation of Stage I Non–Small Cell Lung Cancer and Lung Metastases

“…Use of HFJV was primarily introduced to achieve immobilization for accurate targeting in single-fraction stereotactic radiotherapy of lung tumors, because pinpointing the target was of crucial significance, as it had to be eradicated with a single shot. As already reported (3,16,17), and in accordance with our experience, the abdominal compression device integrated into the stereotactic frame often limits tumor movement inadequately. In contrast to non-HFJV SBRT patient set-up uncertainties under general anesthesia and HFJV have not been observed.…”

“…This method has already been tested with a preclinical animal study in SBRT for the liver [21] and has been established as the best procedure for single-fraction SBRT of metastases of the liver in our clinic [16]. Its feasibility in SBRT for the lungs was uncertain at the outset, but our standardized procedure has proved effective for all of the patients.…”

Reply to: High-Frequency Jet Ventilation for HIFU

“…The reports we have cited consider the application of HFJV to radiation therapy, percutaneous thermal ablation, or extracorporeal shock wave lithotripsy. To summarize, Fritz et al [3], working with radiotherapy, showed that HFJV enabled liver motion to be minimized to 3 mm, in agreement with Denys et al experience. In the field of percutaneous ablation, the only series we found in literature was a retrospective observational study published in 2011 in which nine patients with hepatic or renal lesions were treated under HFJV [4].…”

Use of high-frequency jet ventilation for respiratory immobilization during coronary artery CT angiography

“…In a retrospective comparison of HFJV to spontaneous ventilation in patients undergoing extracorporeal shock wave lithotripsy, Cormack et al [4] found a significant decrease in the number of shocks necessary to obtain stone ablation. Fritz and colleagues [5] showed, in 10 patients, that HFJV produced reliable immobilization of gold markers placed stereotactically in the liver during tumor biopsy. LaraGuerra et al [6] showed that conditions for CT-guided excision of lung nodules in ex vivo lungs with HFJV approached those of inflation to total lung capacity or total lung deflation.…”