METHODS: Radiofrequency and microwave ablation of liver tumours were performed on 20 patients (40 lesions) with the assistance of a CT-guided robotic positioning system. The accuracy of probe placement, number of readjustments and total radiation dose to each patient were recorded. The performance level was evaluated on a five-point scale (5-1: excellent-poor). The radiation doses were compared against 30 patients with 48 lesions (control) treated without robotic assistance.
RESULTS: Thermal ablation was successfully completed in 20 patients with 40 lesions and confirmed on multiphasic contrast-enhanced CT. No procedure related complications were noted in this study. The average number of needle readjustment was 0.8 ± 0.8. The total CT dose (DLP) for the entire robotic assisted thermal ablation was 1382 ± 536 mGy.cm, while the CT fluoroscopic dose (DLP) per lesion was 352 ± 228 mGy.cm. There was no statistically significant (p > 0.05) dose reduction found between the robotic-assisted versus the conventional method.
CONCLUSION: This study revealed that robotic-assisted planning and needle placement appears to be safe, with high accuracy and a comparable radiation dose to patients.
KEY POINTS: • Clinical experience on liver thermal ablation using CT-guided robotic system is reported. • The technical success, radiation dose, safety and performance level were assessed. • Thermal ablations were successfully performed, with an average performance score of 4.4/5.0. • Robotic-assisted ablation can potentially increase capabilities of less skilled interventional radiologists. • Cost-effectiveness needs to be proven in further studies.
METHODS: We report our preliminary experience of performing radiofrequency ablation of the liver using a robotic-assisted CT guidance system on 11 patients (17 lesions).
RESULTS/CONCLUSION: Robotic-assisted planning and needle placement appears to have high accuracy, is technically easier than the non-robotic-assisted procedure, and involves a significantly lower radiation dose to both patient and support staff.
KEY POINTS: • An early experience of robotic-assisted radiofrequency ablation is reported • Robotic-assisted RFA improves accuracy of hepatic lesion targeting • Robotic-assisted RFA makes the procedure technically easier with significant lower radiation dose.
OBJECTIVE: The purpose of this study was to report the worldwide experience with successful retrieval of the Micra TPS.
METHODS: A list of all successful retrievals of the currently available leadless pacemakers (LPs) was obtained from the manufacturer of Micra TPS. Pertinent details of retrieval, such as indication, days postimplantation, equipment used, complications, and postretrieval management, were obtained from the database collected by the manufacturer. Other procedural details were obtained directly from the operators at each participating site.
RESULTS: Data from the manufacturer consisted of 40 successful retrievals of the Micra TPS. Operators for 29 retrievals (73%) provided the consent and procedural details. Of the 29 retrievals, 11 patients underwent retrieval during the initial procedure (immediate retrieval); the other 18 patients underwent retrieval during a separate procedure (delayed retrieval). Median duration before delayed retrieval was 46 days (range 1-95 days). The most common reason for immediate retrieval was elevated pacing threshold after tether removal. The most common reasons for delayed retrieval included elevated pacing threshold at follow-up, endovascular infection, and need for transvenous device. Mean procedure duration was 63.11 ± 56 minutes. All retrievals involved snaring via a Micra TPS delivery catheter or steerable sheath. No serious complications occurred during the reported retrievals.
CONCLUSION: Early retrieval of the Micra TPS is feasible and safe.
METHODS: All relevant studies were identified through keyword searches in electronic databases from inception until September 2020. The searched publications were reviewed, categorised and analysed based on their respective methodology.
RESULTS: Hundred and one publications were identified which utilised existing MC-based applications/programs or customised MC simulations. Two outstanding challenges were identified that contribute to uncertainties in the virtual simulation reconstruction. The first challenge involves the use of anatomical models to represent individuals. Currently, phantom libraries best balance the needs of clinical practicality with those of specificity. However, mismatches of anatomical variations including body size and organ shape can create significant discrepancies in dose estimations. The second challenge is that the exact positioning of the patient relative to the beam is generally unknown. Most dose prediction models assume the patient is located centrally on the examination couch, which can lead to significant errors.
CONCLUSION: The continuing rise of computing power suggests a near future where MC methods become practical for routine clinical dosimetry. Dynamic, deformable phantoms help to improve patient specificity, but at present are only limited to adjustment of gross body volume. Dynamic internal organ displacement or reshaping is likely the next logical frontier. Image-based alignment is probably the most promising solution to enable this, but it must be automated to be clinically practical.
METHODS: Computed tomography scans from 74 patients were retrospectively evaluated between January 2008 and December 2012. Pedicle perforations were classified by two types of grading systems. For medial, lateral, superior and inferior perforations: grade 0 - no violation; grade 1 - <2 mm; grade 2 - 2-4 mm and grade 3 - >4 mm. For anterior perforations: grade 0 - no violation; grade 1 - <4 mm; grade 2 - 4-6 mm and grade 3 - >6 mm.
RESULTS: There were 35 (47.3%) male and 39 (52.7%) female patients with a total 260 thoracic pedicle screws (T1-T6) analysed. There were 32 screw perforations which account to a perforation rate of 12.3% (11.2% grade 1, 0.7% grade 2 and 0.4% grade 3). None led to pedicle screw-related complications. The perforation rate was highest at T1 (33.3%, all grade 1 perforations), followed by T6 (14.5%) and T4 (14.0%).
CONCLUSION: Fluoroscopic guided percutaneous pedicle screws of the upper thoracic spine (T1-T6) are technically more demanding and carry potential risks of serious complications. Extra precautions need to be taken when fluoroscopic guided percutaneous pedicle screws are placed at T1 and T2 levels, due to high medial pedicular angulation and obstruction of lateral fluoroscopic images by the shoulder girdle and at T4-T6 levels, due to smaller pedicular width.