Estimated effective dose of CT-guided percutaneous cryoablation of liver tumors

Abstract

Purpose To estimate effective dose during CT-guided cryoablation of liver tumors, and to assess which procedural factors contribute most to dose. Materials and methods Our institutional review board approved this retrospective, HIPAA-compliant study. A total of 20 CT-guided percutaneous liver tumor cryoablation procedures were performed in 18 patients. Effective dose was determined by multiplying the dose length product for each CT scan obtained during the procedure by a conversion factor (0.015 mSv/mGy-cm), and calculating the sum for each phase of the procedure: planning, targeting, monitoring, and post-ablation survey. Effective dose of each phase was compared using a repeated measures analysis. Using Spearman correlation coefficients, effective doses were correlated with procedural factors including number of scans, ratio of targeting distance to tumor size, anesthesia type, number of applicators, performance of ancillary procedures (hydrodissection and biopsy), and use of CT fluoroscopy. Results Effective dose per procedure was 72 ± 18 mSv. The effective dose of targeting (37.5 ± 12.5 mSv) was the largest component compared to the effective dose of the planning phase (4.8 ± 2.2 mSv), the monitoring phase (25.5 ± 6.8 mSv), and the post-ablation survey (4.1 ± 1.9 mSv) phase (p < 0.05). Effective dose correlated positively only with the number of scans (p < 0.01). Conclusions The effective dose of CT-guided percutaneous cryoablation of liver tumors can be substantial. Reducing the number of scans during the procedure is likely to have the greatest effect on lowering dose.

Radiation dose during CT-guided percutaneous cryoablation of renal tumors: Effect of a dose reduction protocol

“…Reports describing radiation dose from CT-guided liver tumor ablation procedures suggest an almost two-fold greater radiation exposure during cryoablation compared to RFA procedures [15][16]. One of these reports also found almost three times the radiation exposure from CT-guided renal cryoablation procedures compared to CT-guided liver RFA procedures [16].…”

Sonographically Guided Transhepatic Core Biopsies of Right Renal and Adrenal Masses

“…Computed tomographically guided biopsies expose these patients to a considerable radiation dose incurred during the biopsy procedure. Reportedly, the mean effective dose for CT‐guided biopsy is 23 mSv, 22 whereas those of coronary angioplasty, routine abdominal CT, and abdominal angiography are 7, 8.9, and 12 mSv, respectively 23 , 24 . Previous studies preferred to use CT‐guided biopsies of adrenal masses compared to renal masses because sonography provided poor accessibility to adrenal masses 8 , 9 , 13 – 15 .…”

Protection from injury of organs adjacent to a renal tumor during percutaneous cryoablation

“…Park et al . reported cases of cryoablation for liver tumors wherein the bowel was dislocated away from the ablation zone . Hydrodissection was accomplished with the injection of 200–350 mL of normal saline through a 22‐G needle.…”