Lipiodol accumulation patterns and their impact on survival outcomes in transarterial chemoembolization for hepatocellular carcinoma: a single institution retrospective analysis.

Conventional Transarterial chemoembolization (TACE) using Lipiodol is a pivotal therapeutic modality for hepatocellular carcinoma (HCC). The link between Lipiodol accumulation patterns and patient survival outcomes remains underexplored. This study assesses the impact of these patterns on the prognosis of HCC patients undergoing TACE. We evaluated HCC patients treated with selective TACE between July 2015 and March 2020, classifying post-procedure Lipiodol accumulation observed on CT scans into four distinct patterns: homogeneous, heterogeneous, defective, and deficient. We analyzed cumulative local tumor recurrence (LTR), progression-free survival (PFS), and overall survival (OS) rates across these groups. Univariate and multivariate logistic regression analyses were performed to identify potential prognostic factors influencing PFS and OS. Among 124 HCC nodules, the distribution of Lipiodol patterns was: 65 homogeneous, 24 heterogeneous, 10 defective, and 25 deficient. Median PFS was 33.2, 9.1, 1.1, and 1.0 months, respectively, while median OS spanned 54.8, 44.5, 25.0, and 29.1 months for these groups. A significant difference in survival was found only between the homogeneous and defective patterns (hazard ratio, 2.33; confidence interval 1.25-4.36). Multivariate analyses revealed nonhomogeneous patterns as significant predictors of shorter PFS (HR 6.45, p < 0.001) and OS (HR 1.73, p = 0.033). Nonhomogeneous Lipiodol patterns in HCC following TACE significantly correlate with higher recurrence and decreased survival rates, especially with defective patterns. Early detection of these patterns may guide timely intervention strategies, potentially enhancing survival outcomes for patients with HCC.

Efficacy of CalliSpheres® drug-loaded microspheres combined with doxorubicin in hepatocellular carcinoma.

OBJECTIVE: This study compared the efficacy and safety of the transarterial chemoembolization with CalliSpheres® drug-eluting beads loading with doxorubicin (DEB-TACE) versus conventional lipiodol (cTACE) in patients with unresectable hepatocellular carcinoma (HCC). METHODS: A randomized controlled trial (RCT) was conducted with 144 patients, who were randomly assigned to receive either DEB-TACE with doxorubicin-loaded CalliSpheres® microspheres or cTACE with doxorubicin-lipiodol emulsion. Patients were followed up for 12 months, with assessments at 3 and 12 months posttreatment. The primary endpoint was the clinical response rate (CR), and the secondary endpoints were the overall survival (OS), the progression-free survival (PFS), and the safety profile of the two treatments. RESULTS: The results showed that DEB-TACE was superior to cTACE in terms of CR (50.0% vs 30.6% at 3 months, p = 0.03; 43.1% vs 25.0% at 12 months, p = 0.04), OS (18.2 months vs 14.6 months, p < 0.05), and PFS (7.4 months vs 4.8 months, p < 0.05), and that the safety profile of the two treatments was similar (p > 0.05 for all comparisons). However, the efficacy of DEB-TACE and cTACE varied according to the tumor morphology. DEB-TACE showed better CR rates in patients with nodular tumors, while no significant difference in CR between the two groups in patients with infiltrative tumors. CONCLUSION: DEB-TACE showed superior efficacy to cTACE in terms of CR, OS, and PFS, particularly in patients with nodular tumors, while maintaining a similar safety profile. These findings suggest that tumor morphology could inform treatment decisions for TACE in HCC patients.

No lipiodol, no beads-another transcatheter arterial chemoembolization (TACE) with fine cisplatin powder and porous gelatin particles for TACE-naïve, multifocal, up-to-seven out hepatocellular carcinoma.

AIM: The Japanese Interventional oncology group (JIVROSG) showed the efficacy and safety of nonselective transarterial chemoembolization (TACE) with fine cisplatin powder (diamminedichloroplatinum; DDP-H) (65 mg/m2) and porous gelatin particles (DDP-H TACE) without lipiodol for extensive multifocal hepatocellular carcinoma (HCC). However, there are no studies on this method following the JIVROSG study. Therefore, we aimed to evaluate the efficacy of this new DDP-H TACE and its effect on liver function. METHODS: We retrospectively reviewed the medical records of TACE-naïve patients with multifocal HCC (Child-Pugh class A, up-to-seven out, no prior history of systemic therapy) who underwent whole-liver DDP-H TACE between January 2006 and December 2019. RESULTS: Sixty patients were included in this study. The median age of the patients was 71 (range, 35-88) years. The median maximum size of tumors was 26 (range, 8-184) mm; 86.7% of patients met the up-to-11 criteria out. The overall survival duration was 30.3 months. At the time of initial evaluation (median, 45 days), the overall response rate was 65.0%; the disease control rate was 86.7% based on the modified response evaluation criteria in solid tumors guideline. Although nine patients' liver function had deteriorated to Child-Pugh class B at initial evaluation, six of them recovered to Child-Pugh class A. Only three patients (5%) showed permanently impaired liver function. CONCLUSIONS: Whole-liver DDP-H TACE without lipiodol or beads effectively reduced tumors and preserved liver function.

Combined Percutaneous Transhepatic Lymphatic Embolization and Peroral Duodenal Mucosal Radiofrequency Ablation to Manage Protein-Losing Enteropathy.

Percutaneous transhepatic lymphatic embolization (PTLE) and peroral esophagogastroduodenoscopy (EGD) duodenal mucosal radiofrequency (RF) ablation were performed to manage protein-losing enteropathy (PLE) in patients with congenital heart disease. Five procedures were performed in 4 patients (3 men and 1 woman; median age, 49 years; range, 31-71 years). Transhepatic lymphangiography demonstrated abnormal periduodenal lymphatic channels. After methylene blue injection through transhepatic access, subsequent EGD evaluation showed methylene blue extravasation at various sites in the duodenal mucosa. Endoscopic RF ablation of the leakage sites followed by PTLE using 3:1 ethiodized oil-to-n-butyl cyanoacrylate glue ratio resulted in improved symptoms and serum albumin levels (before procedure, 2.6 g/dL [SD ± 0.2]; after procedure, 3.5 g/dL [SD ± 0.4]; P = .004) over a median follow-up of 16 months (range, 5-20 months). Transhepatic lymphangiography and methylene blue injection with EGD evaluation of the duodenal mucosa can help diagnose PLE. Combined PTLE and EGD-RF ablation is an option to treat patients with PLE.

Clinical Outcomes of Use of the Porous Glass Membrane Pumping Emulsification Device During Transarterial Chemoembolization for Hepatocellular Carcinoma.

BACKGROUND/AIM: The porous glass membrane pumping emulsification device enhances local therapeutic effects of transarterial chemoembolization for hepatocellular carcinoma (HCC); however, limited clinical outcomes have been reported. This study aimed to investigate the efficacy and safety of transarterial chemoembolization using the glass membrane pumping emulsification device for HCC. PATIENTS AND METHODS: Between 2019 and 2023, 58 patients (median age=73 years) with unresectable HCC underwent 73 transarterial chemoembolizations using the glass membrane pumping emulsification device at the Nagoya University Hospital. Treatment effects were assessed using contrast-enhanced computed tomography 1-3 months after therapy and every 2-3 months thereafter. RESULTS: The median size of treated tumors was 25.5 mm (45 solitary nodules). The median dosage of ethiodized oil mixed with the epirubicin solution was 3 ml. Complete and partial response were observed in 73% and 11% of patients, respectively. Local control rates at 6 and 12 months were 82.8% and 59.8%, respectively. The median time to recurrence after treatment was 581 days. No major treatment-related complications occurred. The number of tumors and therapeutic effects of the initial transarterial chemoembolization were significantly associated with better local control. CONCLUSION: The glass membrane pumping emulsification device facilitated the accumulation of more concentrated ethiodized oil within the tumor and effective local control.

Sustained release hypoxia-activated prodrug-loaded BSA nanoparticles enhance transarterial chemoembolization against hepatocellular carcinoma.

Transarterial chemoembolization (TACE) is the standard of care for patients with advanced hepatocellular carcinoma (HCC), but facing the problem of low therapeutic effect. Conventional TACE formulations contain Lipiodol (LP) and chemotherapeutic agents characterized by burst release due to the unstable emulsion. Herein, we developed a novel TACE system by inducing bovine serum albumin (BSA) loaded hypoxia-activated prodrug (tirapazamine, TPZ) nanoparticle (BSATPZ) for sustained drug release. In the rabbit VX2 liver cancer model, TACE treatment induced a long-term hypoxic tumor microenvironment as demonstrated by increased expression of HIF-1α in the tumor. BSATPZ nanoparticles combined with LP greatly enhanced the anti-tumor effects of the TACE treatment. Compared to conventional TACE treatment, BSATPZ nanoparticle-based TACE therapy more significantly delayed tumor progression and inhibited the metastases in the lungs. The effects could be partially mediated by the rebuilt immune responses, as BSATPZ nanoparticle can served as an immunogenic cell death (ICD) inducer. Collectively, our results suggest that BSATPZ nanoparticle-based TACE therapy could be a promising strategy to improve clinical outcomes for patients with HCC and provide a preclinical rationale for evaluating TPZ therapy in clinical studies.

Laparoscopic Anatomical Cranial Sub-segmentectomy of Segment VII (S7) with Super-Selective Intra-arterial Nano-ICG Positive Staining-Guided Trans-Parenchymal Approach.

BACKGROUND: With introduction of "cone unit," which is the smallest resectable anatomical area supplied by a tertiary branch of Glissonean pedicle, more precise subsegmental anatomical resection has been proposed.1 Super-selective intra-arterial ICG staining, delivering ICG and lipiodol mixing to arterial branch using interventional radiology, has been proved feasibility especially for complicated anatomy.2-6 It was difficult to uniformly mix water-soluble ICG with lipophilic lipiodol, rendering to inconsistency development of liver segment between angiography and laparoscopy. Nano-ICG is a uniform mixing of ICG and lipiodol.7 We demonstrated an exclusive "two-step" method to perform LAR for cranial S7 via super-selective intra-arterial nano-ICG staining guidance. METHODS: A 70-year-old male was admitted. CT scan showed tumor was located in cranial S7 with 2.1*1.9 cm. Preoperative AFP was 4.66 ng/ml and PIVKA-II was 2332 mAU/ml. The liver function was Child-Pugh class A and ICG-15R was 7.8%. Given that tumor was confined to cranial S7, precise anatomical sub-segmentectomy was warranted. This study was approved by the West China Hospital, Sichuan University Ethics Committee (approval number: 2023-2327). RESULTS: The operation was performed "two step." "First step" was super-selective intra-arterial nano-ICG embolization in intervention room, while "second step" was performed in operation room. ICG demarcation line was clearly identified even after 7 hr. After full mobilization of right hemiliver, we performed transparenchymal approach to find and clamp pedicle of cranial S7 under fluorescence guidance. Operation time was 150 min with 20 ml of blood loss with uneventful course. CONCLUSIONS: Although LAR of S7 remains challenging, super-selective intra-arterial nano-ICG positive staining guidance might be a feasible and safe option.

Re-188 lipiodol in hepatocellular carcinoma with portal vein thrombosis: a pilot study using novel chelating agent N-DEDC and its comparison with (A)HDD.

OBJECTIVE: Hepatocellular carcinoma (HCC) with portal vein thrombosis (PVT) have limited therapeutic options, Re-188 lipiodol transarterial therapy being one of them. We aimed to assess the safety and efficacy of Re-188 lipiodol exclusively in HCC with PVT as well as to compare two chelating agents for the synthesis of Re-188 lipiodol: novel bis-(diethyldithiocarbamato) nitrido (N-DEDC) with existing acetylated 4-hexadecyl 1-2,9,9-tetramethyl-4,7-diaza-1,10-decanethiol [(A)HDD]. METHODS: Patients with radiological diagnosis of HCC with PVT having Eastern Cooperative Oncology Group (ECOG) performance status ≤2 and Child Pugh score (PS) A or B were recruited. Patients received an empirical dose of transarterial Re-188 lipiodol, labelled with (A)HDD or N-DEDC. Radiological response on MRI (modified response evaluation criteria in solid tumors), biochemical response with serum alpha fetoprotein and clinical response with ECOG PS was assessed at three months and survival was estimated at the end of the study. RESULTS: Fifteen therapies were performed in 14 patients with a median age of 62 years (range: 41-70 years). Eight therapies were with Re-188 (A)HDD lipiodol and seven with Re-188 N-DEDC lipiodol. Overall mean injected dose was 2.6 ±â€…0.37 GBq. Radiological objective response rate was 31% and disease control rate was 85%. Mean overall survival was 14.21 months and mean progression free survival was 10.23 months. Percentage survival assessed at 3, 6 and 9 months was 93%, 64% and 57%, respectively. Safety parameters, response and survival outcome were comparable for (A)HDD and N-DEDC groups. CONCLUSION: Transarterial Re-188 lipiodol in HCC with PVT is safe and effective in disease control as well as improving survival outcome. Additionally, cost-effective and high-yielding novel agent N-DEDC appears to be a comparable alternative to (A)HDD for the same.

Transcatheter Arterial Embolization with Bleomycin-Lipiodol of Hepatic Hemangiomas: Safety, Efficacy and Predictors of Response.

PURPOSE: To evaluate the safety, efficacy and predictors of response of transcatheter arterial embolization (TAE) to treat hepatic hemangiomas (HHs). MATERIALS AND METHODS: A retrospective analysis was conducted of consecutive HH patients who received TAE with bleomycin-Lipiodol emulsion and gelatin sponge particles at three institutions from January 2014 to January 2021. TAE effectiveness was defined as more than 50% reduction of tumor volume. The effectiveness, safety, and CT changes of hemangiomas after TAE were assessed. Factors affecting TAE efficacy on tumor size were analyzed with logistic regression analysis. RESULTS: A total of 102 patients with 109 HHs were included. After treatment, both the tumor diameter and volume were significantly reduced from 8.5 ± 3.9 to 5.9 ± 3.8 cm (P < 0.001) and 412.6 ± 742.3 cm3 to 102.0 ± 232.7 cm3 (P < 0.001), respectively. TAE effectiveness was achieved in 80.7% (88/109) of hemangiomas, which was characterized by progressive reduction in tumor volume over time with Lipiodol retention. Atypical enhancement pattern (tiny enhancing dots in the hepatic arterial and portal venous phase) (p = 0.001) and central arterioportal shunt (APS) (p = 0.002) associated with the tumor were independent predictors of TAE ineffectiveness. Postembolization syndrome and transient increase in liver enzymes were common without severe complications and death. CONCLUSION: TAE was safe and effective in reducing HH size. Lesion enhancement pattern and APS type were associated with TAE efficacy on tumor shrinkage. LEVEL OF EVIDENCE: Level 3, non-controlled retrospective cohort study.

Transarterial embolization with bleomycin-lipiodol emulsion: a successful minimal invasive approach for giant liver hemangioma.

Hemangiomas are most common benign liver tumor. Most patients have an excellent prognosis because of the small size and benign nature of tumor. On some occasions, giant liver hemangioma may cause symptoms and significant challenges due to its complication. We report a case of giant liver hemangioma treated with minimal invasive approach by transarterial embolization (TAE). Following three TAE sessions over a specific timeframe, the patient was successfully managed, addressing that TAE may be a useful alternative to hepatic surgery in such cases.

Effect of iodized oil embolization on temperature change during cryoablation for renal cell carcinoma.

INTRODUCTION: We aimed to evaluate the effect of transcatheter arterial embolization (TAE) with iodized oil (Lipiodol) on temperature change during cryoablation (CA) for renal cell carcinoma (RCC). MATERIAL AND METHODS: We retrospectively reviewed patients receiving CA for RCC from February 2020 to July 2021, including those who received Lipiodol TAE prior to CA (TAE group) and those who underwent only CA with comparable clinical and tumor characteristics (non-TAE group). Clinical data and tumor characteristics of both groups were recorded. The temperature readings of each cryoprobe at every 15 s and 'time to -100 °C' were compared between the groups. RESULTS: A total of 17 patients with 18 RCCs were recruited (seven in the TAE group and 11 in the non-TAE group). The 'time to -100 °C' was significantly longer in the TAE group than in the non-TAE group (64.5 ± 24.3 s vs. 48.8 ± 9.7 s, p = 0.018). Positive correlation between 'time to -100 °C' and tumor maximal diameter, RENAL nephrometry and PADUA score were observed in the non-TAE group, while no corresponding correlation was found in the TAE group. CONCLUSIONS: Pre-embolization with iodized oil influences the temporal temperature changes during cryoablation by disrupting the positive correlation between the time to reach the target temperature and tumor characteristics.

Hug sign in intraprocedural cone-beam-CT to predict short-term response to combined treatment of hepatocellular carcinoma.

OBJECTIVES: Combined treatment of ablation and chemoembolization for hepatocellular carcinoma represents a promising therapy to increase treatment efficacy and improve patient survival. The "hug sign" is a recently introduced radiological sign consisting in deposition of beads/contrast agent during transarterial chemoembolization in the hyperemic area surrounding the post-ablation volume, seen during intraprocedural unenhanced cone-beam CT, that may indicate intraprocedural success. Aim of our retrospective study was to analyze the usefulness of the "hug sign" at the intraprocedural unenhanced cone-beam CT as an early predictor of response to combined treatment, based on the hug sign angle. MATERIALS AND METHODS: Between January 2017 and September 2021 all patients with hepatocellular carcinoma which underwent a combined treatment of thermal ablation followed by chemoembolization were enrolled. All treated patients underwent immediate post-procedural unenhanced cone-beam CT to evaluate the deposition of contrast agent, lipiodol or radiopaque beads and to assess the percentage of coverage of the ablated area with the contrast agent (hug sign angle). Patients with missing pre-procedural, intra-procedural and/or post-procedural data/imaging, or with poor-quality post-procedural cone-beam CT images were excluded. RESULTS: 128 patients (mean age, 69.3 years ± 1.1 [standard deviation]; 87 men) were evaluated. Our study evidenced that 84.4% (81/85) of patients with a hug sign angle of 360° had no residual tumor at the first 1-/3-months follow-up examination. A hug sign angle of 360° also showed to be an independent protective factor against residual tumor at multivariate analysis. CONCLUSION: Unenhanced cone-beam CT performed at the end of a combined treatment with ablation plus chemoembolization can effectively predict an early treatment response on radiological images, when a hug sign angle of 360° was detected.

Ultrasound-guided Lipiodol® hysterosalpingography: A prospective study on pregnancy and complication rates.

BACKGROUND: Fluoroscopic hysterosalpingography (HSG) with Lipiodol® is safe and has a therapeutic effect on fertility: transient in endometriosis-related infertility and sustained in unexplained infertility. Ultrasound is replacing fluoroscopy as the preferred imaging modality for HSG due to comfort and radiation safety (no ionising radiation). The safety of ultrasound-guided Lipiodol® HSG is uncertain. AIMS: Prospectively observe pregnancy and complication rates after ultrasound-guided Lipiodol® HSG. MATERIALS AND METHODS: A single-centre prospective study of women with unexplained infertility undergoing ultrasound-guided Lipiodol® uterine bathing and tubal flushing after tubal patency confirmed with ExEm® Foam HyFoSy (hysterosalpingo-foam-sonography). Pregnancy outcomes at six months and serum and urinary thyroid function at one, three and eight weeks were recorded. Pain scores were recorded during and immediately after HSG. Descriptive statistics are reported. RESULTS: Fifty-two participants were enrolled between July 2019 and April 2021, median age 33 years (range 21-45). Only 45 (87%, 45/52) completed the Lipiodol® HSG; 5/7 experienced intravasation during initial HyFoSy. Of 30 women at follow-up, 57% had biochemical (17/30, 95% CI 37%-75%), 53% clinical (16/30 95% CI 34%-72%) and 35% ongoing pregnancies (11/30, 95% CI 20%-56%). The rate of subclinical hypothyroidism (SCH) at two months was 41% (7/17). One intravasation event occurred during Lipiodol® HSG (2%, 1/45). Median pain score was 5/10 (range 0-9, interquartile range 2.5-7). No anaphylaxis, infection or oil embolism was observed. CONCLUSION: Outpatient ultrasound-guided Lipiodol® HSG was safe, with pregnancy rates comparable to previous studies of fluoroscopic guidance. Rates of intravasation and SCH were also similar, confirming the need to monitor thyroid function.

Treatment Of Post-Operative Chylothorax: The Role Of Intranodal Lymphangiography And Thoracic Duct Disruption.

Thoracic duct embolization has been increasingly adopted as a first-line therapy of chylothorax and this procedure includes lipiodol lymphangiography, thoracic duct access and embolization. Lymphangiography itself has a therapeutic role, with volume-dependent success rates of 37%-97% and even a reported 100% success rate in outputs of < 500 mL/day. We present a clinical case of a 48-years-old man diagnosed with esophageal squamous cell carcinoma, who underwent esophagectomy and presented with post-operative high-output (> 1L/day) chylothorax; thoracic duct embolization was proposed. Even though thoracic duct access and embolization were not achieved due to technical and anatomical factors, lipiodol lymphangiography and possibly thoracic duct maceration (after several punctures/attempts) contributed to the clinical success of the procedure, and this chylothorax with output values superior to those reported in the literature resolved within three days. As such, the therapeutic role of intranodal lymphangiography and thoracic duct disruption should be taken into account.

Synthesis and characterization of 3-in-1 multifunctional lipiodol-doped Fe3O4@Poly (diallyl isophthalate) microspheres for arterial embolization, chemotherapy, and imaging.

Transcatheter arterial embolization plays a pivotal role in treating various diseases. However, the efficacy of embolization therapy in cancer treatment can be limited by several factors, such as inevitable incomplete or non-target embolization, and the tumor recurrence and metastasis caused by the hypoxic microenvironment. Moreover, it is essential to explore simpler, more economical, and efficient methods for microsphere synthesis. Herein, we achieved one-step photocatalytic synthesis of lipiodol-doped Fe3O4@Poly (diallyliso-phthalate) multifunctional microspheres (IFeD MS) for arterial embolization, chemotherapy, and imaging. The prepared microspheres are in the shape of dried plums, with a particle size of 100-300 µm. Lipiodol demonstrates a certain degree of chemotherapeutic activity, and the incorporation of Fe3O4enables the microspheres to exhibit magnetothermal response and magnetic resonance imaging capabilities. Furthermore, the radiopaque characteristics of both agents provide the microspheres with promising potential for computed tomography and digital radiography imaging. The renal embolization experiment in rabbits demonstrated that IFeD MS achieved significant embolization and chemotherapeutic effects. Biocompatibility experiments revealed that this embolic agent did not induce tissue damage or inflammation beyond the treatment area. Additionally, IFeD MS exhibited promising imaging potential. The results of this study imply that the developed multifunctional embolic agent IFeD MS may have significant potential in transforming tumors previously only suitable for palliative cares into resectable radical treatments.

Effect of lipiodol marking before CT-guided cryoablation on the outcome of sporadic renal cell carcinoma.

PURPOSE: This retrospective study evaluates the impact of preoperative lipiodol marking on the outcomes of computed tomography (CT)-guided cryoablation for histologically diagnosed sporadic renal cell carcinoma (RCC). METHODS: This study analyzed the data of 173 patients who underwent CT-guided cryoablation for histologically proven sporadic RCC at a single institution between April 2014 and December 2020. The local control rate (LCR), recurrence-free survival rate (RFSR), overall survival rate (OSR), changes in renal function, and complications in patients with (n = 85) and without (n = 88) preoperative lipiodol marking were compared. RESULTS: The 5-year LCR and 5-year RFSR were significantly higher in patients with lipiodol marking (97.51% and 93.84%, respectively) than in those without (72.38% and 68.10%, respectively) (P value <0.01, log-rank test). There were no significant differences between the two groups regarding the 5-year OSR (97.50% vs. 86.82%) or the deterioration in chronic kidney disease stage (12.70% vs. 16.43%). Grade ≥3 complications occurred in patients with lipiodol marking (n = 2, retroperitoneal hematoma and cerebral infarction in 1 patient each) and without (n = 5; urinary fistula in 2, colonic perforation in 2, urinary infection in 1). CONCLUSION: Lipiodol marking before CT-guided cryoablation for sporadic RCC is a feasible approach to improving local control and RFS while mitigating the decline in renal function. Additionally, it may help reduce complications.

Liver stereotactic body radiation therapy without fiducial or retained ethiodized oil guidance warrants greater than 5 mm planning target volumes.

INTRODUCTION: For liver stereotactic body radiation therapy (SBRT), the placement of fiducial markers or retained ethiodized oil by transarterial chemoembolisation (TACE) provides a landmark for consistent target localisation. TACE and fiducial markers are invasive procedures that harbour additional risks. We hypothesise that liver SBRT can be accurately delivered without the use of these invasive surrogate markers. METHODS: We retrospectively identified 50 consecutive patients who underwent liver SBRT with respiratory motion management to a single lesion which exhibited retained ethiodized oil per prior TACE delivery. For each SBRT fraction, two manual rigid image registrations were performed by the treating physician. One using the liver contour as a surrogate for the target and second aligning only to the radio-opaque retained ethiodized oil of the treated lesion. The magnitude of the displacement vector between the two registration methods was used to assess the accuracy of target localisation if ethiodized oil was not present. RESULTS: For the 50 patients, a total of 244 analysable cone-beam CTs (CBCTs) were included (six CBCTs excluded due to poor ethiodized oil visualisation). Respiratory motion management techniques consisted of active breathing control for 13 and abdominal compression for 37 patients. Forty-two patients had peripheral lesions and eight had central lesions (<2 cm from left and right portal veins). The average target localisation offset between the two registration methods (i.e. liver contour vs. retained ethiodized oil alignment) for patients with a single peripheral or central liver lesion was 5.8 and 5.3 mm, respectively. CONCLUSIONS: Across all patients, the average change in target position exceeded 5 mm for image registration methods based on the liver contour alone versus the retained ethiodized oil region. This suggests that margins greater than 5 mm may be required for respiratory motion-managed liver SBRT treatments in patients who do not undergo prior TACE or fiducial placement.