Feasibility of Yttrium-90 Radioembolization Dose Calculation Utilizing Intra-procedural Open Trajectory Cone Beam CT.

PURPOSE: Dose calculation for transarterial radioembolization (TARE) with glass yttrium-90 (Y90) labeled microspheres is based on liver lobe and tumor volumes, currently measured from preprocedural MRI or CT. The variable time between MRI and radioembolization may not account for relevant tumor progression. Advances in cone beam computed tomography (CBCT) allow for intra-procedural assessment of these volumes that avoids this factor. Liver lobe and hepatocellular carcinoma tumor volume measurements and dose calculations using intra-procedural CBCT were compared to those using preprocedural MRI in order to determine feasibility. METHODS: Retrospective analysis was performed in 20 patients with proven hepatocellular carcinoma (HCC) who underwent planning angiography with open trajectory CBCT acquisitions prior to radioembolization, and an MRI performed within 6 weeks prior to treatment planning. Liver lobe and tumor burden volumes were measured based on CBCT using embolization planning and guidance software and measured on preprocedural MRI using standard volume analysis software. Y90 doses were subsequently calculated using each measured volume. Comparisons of volume measurements and calculated Y90 doses between the two modalities were evaluated for significance using paired t tests. RESULTS: All target liver lobes and all tumors were completely depicted on CBCT. Mean liver lobe and tumor burden volumes measured on intra-procedural CBCT and preprocedural MRI showed no significant difference (p = 0.71). Mean calculated Y90 dose based on each modality showed no significant difference (p = 0.18). CONCLUSIONS: Lobar and tumor volume measurement with CBCT is a reliable alternative to measurement with preprocedural MRI. Utilization of CBCT 3D segmentation software during planning angiography may be useful to provide up-to-date volume measurements and dose calculations prior to radioembolization.

Transradial Approach for Hepatic Radioembolization: Initial Results and Technique.

OBJECTIVE: The transradial approach (TRA) has been shown to reduce the morbidity and mortality associated with arterial coronary interventions. Selective internal radiation therapy (SIRT) performed via the TRA can enhance patient comfort, compared with the traditional transfemoral approach (TFA), by allowing immediate ambulation and precluding potential complications associated with the TFA, such as closure device injury or retroperitoneal hematoma. We report our initial experience with and technique for using the TRA for SIRT. MATERIALS AND METHODS: Between May 1, 2012, and April 30, 2015, a total of 574 procedures, including planning angiograms (n = 329) and infusions of 90Y (n = 245), were performed for 318 patients (mean age, 64.5 years). Of the 245 patients who received 90Y infusions, 52 had SIRT performed with the use of a permanent single-use implant of 90Y resin microspheres and 193 had SIRT performed with the use of millions of small glass microspheres containing radioactive 90Y. Procedural details, technical success, the radial artery (RA) occlusion rate noted at 30 days (as assessed via pulse examination), and the major and minor adverse events noted at 30 days were evaluated. RESULTS: Technical success was achieved in 561 of 574 cases (97.7%). The reasons for crossover to use of the TFA included an RA loop (n = 2), RA occlusion (n = 9), and type D response as determined by use of a Barbeau test (n = 2). Patients had undergone between zero and six previous TRA procedures. The mortality rate at 30 days was 0%. Superficial bruising occurred in 13 of 574 cases (2.3%). A grade 2 hematoma that required a second nonocclusive hemostasis cuff occurred in one case. Transient forearm numbness or pain occurred in two of 574 cases. One patient had a transient convulsive event occur after receiving intraarterial infusion of verapamil. RA occlusion occurred in nine of 574 cases (1.6%). CONCLUSION: Use of the TRA for SIRT is safe, feasible, and well tolerated and is associated with high rates of technical success and rare complications.

Prospective Randomized Trial for Image-Guided Biopsy Using Cone-Beam CT Navigation Compared with Conventional CT.

PURPOSE: To compare cone-beam computed tomography (CT) navigation vs conventional CT image guidance during biopsies. MATERIALS AND METHODS: Patients scheduled for image-guided biopsies were prospectively and randomly assigned to conventional CT guidance vs cone-beam CT navigation. Radiation dose, accuracy of final needle position, rate of histopathologic diagnosis, and number of needle repositions to reach the target (defined as pullback to adjust position) were compared. RESULTS: A total of 58 patients (mean age, 57 y; 62.1% men) were randomized: 29 patients underwent 33 biopsies with CT guidance and 29 patients with 33 lesions underwent biopsy with cone-beam CT navigation. The average body mass index (BMI) was similar between groups, at 28.8 kg/m(2) ± 6.55 (P = .18). There was no difference between groups in terms of patient and lesion characteristics (eg, size, depth). The average lesion size was 29.1 ± 12.7mm for CT group vs 32.1mm ±16.8mm for cone-beam CT group (P < 0.59). Location of lesions was equally divided between the 2 groups, 20 lung lesions, 18 renal lesions and 20 other abdominal lesions. Mean number of needle repositions in the cone-beam CT group was 0.3 ± 0.5, compared with 1.9 ± 2.3 with conventional CT (P < .001). The average skin entry dose was 29% lower with cone-beam CT than with conventional CT (P < .04 accounting for BMI). The average estimated effective dose for the planning scan from phantom data was 49% lower with cone-beam CT vs conventional CT (P = .018). Accuracy, defined as the difference between planned and final needle positions, was 4.9 mm ± 4.1 for the cone-beam CT group, compared with 12.2 mm ± 8.1 for conventional CT (P < .001). Histopathologic diagnosis rates were similar between groups, at 90.9% for conventional CT and 93.9% for cone-beam CT (P = .67). CONCLUSIONS: Cone-beam CT navigation for biopsies improved targeting accuracy with fewer needle repositions, lower skin entry dose, and lower effective dose for planning scan, and a comparable histopathologic diagnosis rate.

Improved Visibility of Metastatic Disease in the Liver During Intra-Arterial Therapy Using Delayed Arterial Phase Cone-Beam CT.

PURPOSE: To compare the visibility of liver metastases on dual-phase cone-beam CT (DP-CBCT) and digital subtraction angiography (DSA), with reference to preinterventional contrast-enhanced magnetic resonance imaging (CE-MRI) of the liver. METHODS: This IRB-approved, retrospective study included 28 patients with neuroendocrine (NELM), colorectal (CRCLM), or sarcoma (SLM) liver metastases who underwent DP-CBCT during intra-arterial therapy (IAT) between 01/2010 and 10/2014. DP-CBCT was acquired after a single contrast agent injection in the tumor-feeding arteries at early and delayed arterial phases (EAP and DAP). The visibility of each lesion was graded by two radiologists in consensus on a three-rank scale (complete, partial, none) on DP-CBCT and DSA images using CE-MRI as reference. RESULTS: 47 NELM, 43 CRCLM, and 16 SLM were included. On DSA 85.1, 44.1, and 37.5 % of NELM, CRCLM, and SLM, were at least partially depicted, respectively. EAP-CBCT yielded significantly higher sensitivities of 88.3 and 87.5 % for CRCLM and SLM, respectively (p < 0.01), but not for NELM (89.4 %; p = 1.0). On DAP-CBCT all NELM, CRCLM, and SLM were visible (p < 0.001). Complete depiction was achieved on DSA for 59.6, 16.3, and 18.8 % of NELM, CRCLM, and SLM, respectively. The complete depiction rate on EAP-CBCT was significantly higher for CRCLM (46.5 %; p < 0.001), lower for NELM (40.4 %; p = 0.592), and similar for SLM (25 %, p = 0.399). On DAP-CBCT however, the highest rates of complete depiction were found-NELM (97.8 %; p = 0.008), CRCLM (95.3 %; p = 0.008), and SLM (100 %; p < 0.001). CONCLUSION: DAP-CBCT substantially improved the visibility of liver metastases during IAT. Future studies need to evaluate the clinical impact.

A prospective case control comparison of the ZeroGravity system versus a standard lead apron as radiation protection strategy in neuroendovascular procedures.

BACKGROUND AND PURPOSE: We aimed to compare the performance of the ZeroGravity (ZG) system (radiation protection system composed by a suspended lead suit) against the use of standard protection (lead apron (LA), thyroid shield, lead eyeglasses, table skirts, and ceiling suspended shield) in neuroangiography procedures. MATERIALS AND METHODS: Radiation exposure data were prospectively collected in consecutive neuroendovascular procedures between December 2014 and February 2015. Operator No 1 was assigned to the use of an LA (plus lead glasses, thyroid shield, and a 1 mm hanging shield at the groin) while operator No 2 utilized the ZG system. Dosimeters were used to measure peak skin dose for the head, thyroid, and left foot. RESULTS: The two operators performed a total of 122 procedures during the study period. The ZG operator was more commonly the primary operator compared with the LA operator (85% vs 71%; p=0.04). The mean anterior-posterior (AP), lateral, and cumulative dose area product (DAP) radiation exposure as well as the mean fluoroscopy time were not statistically different between the operators' cases. The peak skin dose to the head of the operator with LA was 2.1 times higher (3380 vs 1600 µSv), while the thyroid was 13.9 (4460 vs 320 µSv), the mediastinum infinitely (520 vs 0 µSv), and the foot 3.3 times higher (4870 vs 1470 µSv) compared with the ZG operator, leading to an overall accumulated dose 4 times higher. The ratio of cumulative operator received dose/total cumulative DAP was 2.5 higher on the LA operator. CONCLUSIONS: The ZG radiation protection system leads to substantially lower radiation exposure to the operator in neurointerventional procedures. However, substantial exposure may still occur at the level of the lens and thyroid to justify additional protection.