Dose-area product of patients undergoing digital subtraction angiography (DSA): abdominal aorta and lower limb examinations

Digital variance angiography in patients undergoing lower limb arterial recanalization: cost-effectiveness analysis within the English healthcare setting

Aim: Digital variance angiography (DVA) is a recently developed image processing method capable of improving image quality compared with the traditionally used digital subtraction angiography (DSA), among patients undergoing lower limb x-ray angiography. This study aims to explore the potential cost-effectiveness of DVA from an English National Health Service perspective. Materials & methods: A two-part economic model, consisting of a decision tree and a Markov model, was developed to consider the costs and health outcomes associated with the use of DVA as part of current practice imaging, compared with x-ray angiography using standard DSA. The model explored the impact of DVA on the development of acute kidney injury (AKI), chronic kidney disease and radiation-induced cancer over a lifetime horizon. Both deterministic and probabilistic analyses were performed to assess the cost per quality-adjusted life-year (QALY). Results: Base-case results indicate that DVA results in cost savings of £309 per patient, with QALYs also improving (+0.025) over a lifetime. As shown in sensitivity analysis, a key driver of model results is the relative risk (RR) reduction of contrast-associated acute kidney injury associated with use of DVA. The intervention also decreases the risk of carcinoma over a lifetime. Scenario analyses show that cost savings range from £310 to £553, with QALY gains ranging from 0.048 to 0.109 per patient. Conclusion: The use of DVA could result in a decrease in costs and an increase in QALYs over a lifetime, compared with existing imaging practice. The potential for this technology to offer an economically viable alternative to existing image processing methods, through a reduction in contrast media volume and radiation exposure, has been demonstrated.

Physician impact on use of fluoroscopy during endovascular procedures to improve radiation safety

OBJECTIVE

To determine whether differences exist in fluoroscopy time and radiation exposure during lower extremity endovascular procedures performed by fellowship trained vascular surgeons vs general surgeons, to minimize radiation exposure to operating room staff.

METHODS

A retrospective review of all lower extremity endovascular procedures was performed from August 1, 2014, to January 29, 2016. The procedures were performed by the surgical department's four surgeons with endovascular privileges: two vascular surgeons and two general surgeons. Only procedures involving lower extremity arterial angiograms with balloon angioplasty, stenting, or atherectomy were included. The operative records were reviewed for each case. The total fluoroscopy time and total radiation dose for each procedure were recorded. Procedures were grouped according to the number of endovascular interventions as one to two interventions, three to four interventions, and five or more interventions performed. Statistical analysis was performed with a P value of less than .05 considered significant.

RESULTS

About 271 lower extremity endovascular procedures were performed during the study period by 4 surgeons. The average age of the patient population was 70 years. The total number of procedures performed over the study period were 112, 45, 91, and 25 for surgeons 1 through 4, respectively. On average, 3.24 interventions were performed during each procedure. Vascular surgeons were found to have shorter fluoroscopy time for procedures involving one to two (7.8 vs 30.1; P < .01), three to four (9.3 vs 34.2; P < .01), and five or more (11.5 vs 51.9; P < .01) interventions. Vascular surgeons were also found to have less radiation exposure compared with general surgeons in procedures with one to two (1.69 vs 3.53; P = .001) and five or more (2.3 vs 5.4; P = .003) interventions. There was no significant difference in radiation exposure between vascular and general surgeons for procedures with three to four interventions (5.86 vs 5.59; P = .95).

CONCLUSIONS

In this small series at our institution, lower extremity endovascular procedures performed by specialty trained vascular surgeons were associated with both decreased operative fluoroscopy time and decreased radiation exposure when compared with general surgeons.

Radiation dose reduction utilizing noise reduction technology during uterine artery embolization: a pilot study

OBJECTIVE

To assess the radiation dose reduction during uterine artery embolization utilizing dose reduction technology.

METHODS

A total of 58 women underwent uterine artery embolization. A total of 26 procedures were performed in a standard fluoroscopy suite; 32 procedures were performed utilizing a novel imaging platform. Radiation dose data and acquisition parameters were compared.

RESULTS

The new platform provided significant reduction in the median radiation dose (P<.001): from 389Gy cm(2) to 145Gy cm(2). There were no differences between the groups with regard to acquisition parameters.

CONCLUSION

The new imaging platform provided a 61% dose reduction during uterine artery embolization without a significant change in acquisition parameters.

Patient radiation exposure during carotid artery stenting

Objectives

The main purpose of this study was to document the radiation doses to patients during carotid stenting.

Material and method

Fluoroscopy and exposure time, air kerma and dose-area product during carotid artery stenting in 160 patients were retrospectively reviewed with regard to body mass index, degree of stenosis and use of cerebral protection devices.

Results

Total air kerma was lower than 0.5 Gy in 80%, 0.5–1 Gy in 17% and higher than 1 Gy (maximum 1.2) in 3% of patients. Mean total dose-area product value for carotid stenting was 54 Gy cm2. The mean air kerma (fluoroscopy), air kerma (exposure), total air kerma and dose-area product (fluoroscopy), dose-area product (exposure), total dose-area product of patients with body mass index within the range 25–29.9 and with body mass index >30 were significantly increased compared to that of patients with body mass index 18–24.9 (H = 40.2, df = 2; p = 0.0000001 and p = 0.000003, respectively).

Conclusion

Carotid artery stenting is a relatively safe radiological procedure in terms of the radiation dose acquired by the patient. The main factors contributing to possible radiation overdosing are body mass index value and complexity of the carotid lesion. Proper preoperative planning in obese and complicated patients may reduce the fluoroscopy time and contribute to reduced dose acquisition.

Radiation exposure to patients and radiologists during interventional procedures

Patients who undergo interventional radiological examinations and the medical doctors who perform them receive a noticeable radiation dose. Twenty-six angiographies and six angioplasties were included in the present study. They were classified as examinations of lower limbs, abdominal aorta and aortic arch/carotid artery. Thermoluminescent dosemeters (TLDs) were placed underneath and over the lead apron of the doctors at all of the 32 examinations as well as next to the eyes and over the thyroid of 22 patients. Dose area product (DAP) values, time duration and other parameters were registered. Patients' effective dose (ED) and doses to the various organs were calculated with the aid of ODS-60 software. The EDs were normalised to DAP measured in each procedure. Based on TLD measurements, the Niklason method was applied for the calculation of doctors' ED. The calculated ED by ODS-60 were in the range of 0.00-1.46, 2.63-49.32 and 0.07-45.12 mSv for the three groups, respectively, while E/DAP indices were 0.023, 0.310 and 0.105 mSv Gy(-1) cm(-2). Very good correlation was found between TLD measurements of the eye and the thyroid of the patients and the relative values calculated by ODS-60. The ED for the radiologists ranged from 0.4 to 47.0 μSv for all the procedures. Taking into consideration the annual number of examinations performed in the department, the estimated dose to the radiologists' eyes is considerably high, so wearing leaded glasses is recommended for the optimisation of the procedure.

Doses to operators during interventional radiology procedures: focus on eye lens and extremity dosimetry

The present study is focused on the personnel doses during several types of interventional radiology procedures. Apart from the use of the official whole body dosemeters (thermoluminescence dosemeter type), measurements were performed to the extremities and the eyes using thermoluminescent loose pellets. The mean doses per kerma area product were calculated for the monitored anatomic regions and for the most frequent types of procedures. Higher dose values were measured during therapeutic procedures, especially embolisations. The maximum recorded doses during a single procedure were 1.8 mSv to the finger (nephrostomy), 2.1 mSv to the wrist (liver chemoembolisation), 0.6 mSv to the leg (brain embolisation) and 2.4 mSv to the eye (brain embolisation). The annual doses estimated for the operator with the highest workload according to the measurements and the system's log book were 90.4 mSv to the finger, 107.9 mSv to the wrist, 21.6 mSv to the leg and 49.3 mSv to the eye. Finally, the effect of the beam angulation (i.e. projection) and shielding equipment on the personnel doses was evaluated. The measurements were performed within the framework of the ORAMED (Optimization of RAdiation Protection for MEDical staff) project.