Radiation dose to patients and staff during angiography of the lower limbs. Derivation of local dose reference levels.

BACKGROUND: The Euratom directive 97/43 recommends the use of patient dose surveys in diagnostic radiology and the establishment of reference dose levels (DRLs). PURPOSE: To perform measurements of the dose delivered during diagnostic angiography of the lower limbs using thermoluminescence dosimeters (TLDs), extraction of DRLs and estimation of the effective dose and radiation risk for this particular examination. METHODS: Dose measurement was performed on 30 patients by using TLD sachets attached in 5 different positions not only on the patient, but also to the radiologist. All the appropriate factors were recorded. Measurement of the ESD was performed after each examination. RESULTS: The mean entrance skin dose (ESD) was calculated to be 70.8, 67.7, 24.3, 18.4, 9.7 mGy at the level of aorta bifurcation, pelvis, femur, knees, and at feet, respectively. The average effective dose is 9.8 mSv with the radiation risks for fatal cancer to be 5.4 x 10(-4). The effective dose of the radiologist was calculated to be 0.023 mSv per procedure. CONCLUSION: Radiation dose variation depends on the physical characteristics of the patient, on the procedure preferences by radiologists and the difficulties in conducting procedures. The main reason for the increased patient dose, compared to other studies, is the number of frames rather than the duration of fluoroscopy. For DSA of the lower limbs, the DRL was chosen to be an entrance skin dose of 96.4 mGy in the pelvic region. The dose to the radiologist is negligible.

Varicocele embolization: Anatomical variations of the left internal spermatic vein and endovascular treatment with different types of coils.

PURPOSE: To present anatomical variations of left internal spermatic vein and a comparison between treatments with hydrogel-coated and non-coated platinum coils in patients with varicocele. MATERIALS AND METHODS: A total of 153 men (mean age, 27.5±6.7 [SD] years; range: 18-45 years) with left sided varicocele underwent coil embolization. Anatomic variants of gonadal vein were categorized into five subtypes (I-V). Additional venous collaterals were also recorded. Three types of coils were used (hydrogel coated platinum coils, fibered coils and non-coated platinum coils). Technical success, tolerance, efficacy and safety of hydrogel coated platinum coils were recorded. Comparison between different types of coils used was made. Fisher's exact test was used for statistical analysis. RESULTS: Varicoceles were classified as type I (26.1%), type II (13.7%), type III (32.1%), type IV (18.3%) and type V (9.8%). The internal spermatic vein - renal vein angle ranged from 32°-128° (mean angle, 93.5°). Technical success was achieved in 145 patients (94.8%) without complications. The mean number of coils used was 3 (range: 1-6 coils). A total of 260 hydrogel coated platinum coils in 95 patients and 135 non-coated coils in 50 patients were deployed with no complications. No differences were noted between the different types of coils used regarding embolic efficacy and safety. A 6.2% (9/145) recurrence rate and a 33.3% (14/42) fertility rate were observed. Clinical success regarding symptom relief after painful varicocele embolization was 100% (36/36) for technically successful cases. CONCLUSION: Varicocele embolization with the use of hydrogel coated or non-coated platinum coils is technically feasible and safe without complications. No superiority of one type of coil over the other was found.

In vivo dosimetry during DSA of the carotid and renal arteries. Deriviation of local DRLs.

The Euratom directive 97/43 recommends the use of patient dose surveys in diagnostic radiology and the establishment of diagnostic reference dose levels (DRLs). The aims of this study are to perform measurements of the entrance surface dose (ESD) during diagnostic digital subtraction angiography (DSA) of the renal and carotid arteries using thermoluminescence dosemeters (TLDs), extraction of local DRLs, and calculation of the effective dose. Dose measurement for the staff was also performed. Dose measurements were performed on 48 participating patients. The mean effective dose was calculated to be 15.9 mSv and 8.9 mSv, for the renal and carotid DSA, respectively. The effective dose of the radiologist was calculated to be 0.022 mSv and 0.023 mSv per procedure for renal and carotid DSA respectively, when wearing a protective apron and using a movable ceiling mounted shield. Radiation dose variation depends on the physical characteristics of the patient, on the procedure preferences by radiologists and on the difficulties in conducting the procedures. The lack of DRLs for the specific examinations lead the research team to choose the DRL for DSA of the renal arteries to be 169 mGy for ESD at the pelvic region and for DSA of the carotid arteries to be 313 mGy for ESD at the region of the aortic arc.

Minimally invasive and selective hydrodynamic gene therapy of liver segments in the pig and human.

This paper highlights our experience of the transfer of hydrodynamic gene therapy (HGT) from the large animal, the pig, into clinical practice. The modification of balloon catheters and the development of a minimally invasive technique to allow selective isolation of liver segments for HGT in the large animal and human are described. Finally, our preliminary results from a phase I clinical study of HGT for thrombopoietin (TPO) in cirrhotic patients with thrombocytopenia are discussed. Based on these provisional data, minimally invasive selective HGT of liver segments appears to be technically safe, but further work is required to optimize the efficiency of gene transfer in order to achieve clinical benefit.

Imaging modalities for renal artery stenosis in suspected renovascular hypertension: prospective intraindividual comparison of color Doppler US, CT angiography, GD-enhanced MR angiography, and digital substraction angiography.

The aim of the study was to evaluate the diagnostic accuracy of Color Doppler US, CT Angiography (CTA), and GD-enhanced MR Angiography (MRA) compared with digital subtraction angiography (DSA) for the detection of renal artery stenosis in patients with clinically suspected renovascular hypertension. Fifty-eight patients with suspected renovascular hypertension were enrolled in the study. All patients underwent Color Doppler US, CTA and GD-enhanced MRA. DSA was the gold standard method for the number of renal arteries, existence and degree of stenosis, or evidence of fibromuscular dysplasia. DSA depicted 132 renal arteries, 16 stenoses, and 4 arteries with fibromuscular dysplasia. Color Doppler US failed to detect 1 main and 14 polar arteries. CTA depicted all main renal arteries and 7/16 polar arteries, but failed to detect stenosis in two accessory vessels. Likewise, MRA did not detect stenotic accessory renal arteries, depicted 9/16 polar renal arteries, but missed two main renal arteries. All methods depicted the four main renal arteries with fibromuscular dysplasia. The overall sensitivity, specificity, and positive and negative predictive accuracy were 75%, 89.6%, 60% and 94.6%, respectively, for color Doppler US; 94%, 93%, 71%, and 99%, respectively, for CTA; and 90%, 94.1%, 75%, and 98%, respectively, for GD-enhanced MRA. CTA and GD-enhanced MRA have comparable and satisfactory results with respect to the negative predictive accuracy of the suspected renal artery stenosis. The concept of an imaging algorithm including US as screening test when appropriate and CTA or MRA as the second step-procedure is suggested. Therefore, DSA may be reserved for cases with major discrepancies or therapeutic interventions.