[Measurement of Head and Neck Exposure in CT Guided IVR].

In April 2011, the International Radiological Protection Committee recommended that "The equivalent dose of the crystalline lens should not exceed 20 mSv/year, averaged over defined periods of 5 years, with no single year exceeding 50 mSv". Based on this recommendation, it is predicted that the equivalent dose limit of our crystalline lens can be lowered in the near future. Therefore, it is important to grasp the current situation of radiation exposure. The purpose of this study is to measure the crystalline lens of surgeons by focusing on the CT-fluoroscopy guided interventional radiology's (IVRs). We also examined whether the exposure dose of the crystalline lens can be correctly evaluated by measuring the unequal exposure dose of the neck, which is usually used for the unequal exposure measurement. Results of the analysis of 200 CT-fluoroscopy guided IVR procedures showed that the unequal exposure dose of the neck was significantly correlated with the exposure dose of the crystalline lens which was measured near the left eye ball (R=0.83). However, the exposure dose of the crystalline was 33% lower than those of the neck. Therefore, although the individual dosimeter worn on the neck can be used as the useful index of the exposure dose of the crystalline lens, the results can be overestimated.

Percutaneous radiofrequency ablation with transarterial embolization is useful for treatment of stage 1 renal cell carcinoma with surgical risk: results at 2-year mean follow up.

OBJECTIVES: Despite laparoscopic partial nephrectomy and laparoscopic cryotherapy being performed lately, an even less invasive treatment would be desirable in high-risk patients. Under local anesthesia with i.v. sedation, we were able to perform percutaneous radiofrequency ablation (RFA) combined with renal arterial embolization for unresectable stage 1 (T1NoMo) renal cell carcinoma (RCC). We evaluated the feasibility, safety and therapeutic effects of this technique after a 2-year mean follow up. METHODS: Thirty-one patients who were not candidates for surgery underwent RFA for 36 stage 1 RCC. Twenty-eight tumors were percutaneously ablated 6 days after the tumor vessels were embolized. Dynamic contrast-enhanced computed tomography (CT) and magnetic resonance imaging (MRI) were performed to evaluate treatment at completion. RESULTS: Tumor enhancement was eliminated after two RFA sessions in all tumors. Thirty tumors remained free of enhancement during a mean follow-up period of 24.3 months. There were no major complications related to the procedures though one instance of pyonephrosis, two of subcapsular hematomas, one of retroperitoneal hemorrhage and one of nausea were seen after RFA. Two patients died of other diseases (i.e. colon cancer and cerebral bleeding) 20 and 26 months after RFA treatment. One patient had a local recurrence of tumor and underwent re-RFA. The recurrence rate of RCC after successful RFA was 2.8%. There was no recurrence in patients who had tumors of less than 4 cm after RFA at a mean follow-up period of 24.3 months. Local control was achieved in 100% of T1NoMo tumors including the recurrence case that underwent re-RFA. CONCLUSIONS: The result of the present study at 2-year mean follow up showed percutaneous RFA was a feasible, safe and promising therapy for the treatment of unresectable stage 1 RCC, especially those smaller than 4 cm.

Image-guided radiofrequency ablation for adrenocortical adenoma with Cushing syndrome: outcomes after mean follow-up of 33 months.

OBJECTIVES: To evaluate the feasibility, safety, and therapeutic effects of image-guided radiofrequency (RF) ablation used for the treatment of adrenocortical adenoma with Cushing syndrome. METHODS: From February 2003 to May 2005, 4 consecutive patients with adrenocortical adenoma and Cushing syndrome received percutaneous RF ablation. All tumors were in the left adrenal gland, with a mean tumor size of 2.7 +/- 0.6 cm (range 2.0 to 3.5). The RF ablation was performed under real-time computed tomography fluoroscopic guidance. Technical success was defined as disappearance of tumor enhancement on contrast-enhanced computed tomography imaging acquired within 1 week after RF ablation. Clinical success was defined as improvement in serum cortisol and adrenocorticotropic hormone values and symptoms at the end of follow-up. RESULTS: Tumor enhancement disappeared after initial RF ablation in 3 of 4 patients (technical success rate 75%). The fourth patient underwent a repeat RF ablation session 3 years later, resulting in eradication of tumor enhancement. Both the serum cortisol and adrenocorticotropic hormone levels returned to normal and the symptoms related to Cushing syndrome had disappeared at the end of follow-up (range 20 to 46 months, mean 33) for a clinical success rate of 100%. All tumors showed involution (2.2 +/- 0.3 cm) at the end of the study. No major complications occurred related to the procedures except for pneumothorax requiring chest tube placement for 3 days. CONCLUSIONS: Using RF ablation for adrenocortical adenoma with Cushing syndrome is a feasible, safe, and promising treatment method in selected patients.