Variations in dose to the extremities of vascular/interventional radiologists

Radiation hand exposure during restoration of flow to the thrombosed dialysis access graft

PURPOSE

To determine radiation dose to the hands of interventional radiologists during restoration of flow to thrombosed dialysis access grafts.

MATERIALS AND METHODS

Sixty-two procedures were performed in 54 patients with thrombosed synthetic arteriovenous hemodialysis access grafts. For each procedure, five staff interventional radiologists wore thermoluminescent ring dosimeters on each hand. Overall hand doses were obtained, and patient and graft factors as well as technical factors were analyzed to determine the effects on hand exposure.

RESULTS

The mean right hand and left hand exposures were 0.78 mSv and 0.55 mSv (78 and 55 mrem), respectively, and there was a significant difference between the two (P = .01). There was a significant difference among the interventionalists, mostly based on the lower doses associated with a single operator (P < .01). Not unexpectedly, fluoroscopy times (P < .01) and, to a lesser degree, the number of angiographic runs (P = .05) were significant factors influencing hand radiation dose. Patient sex, age and location of the graft, previous thrombosis, the number of previous interventions, and success or failure of the procedure were not significant factors in hand dose.

CONCLUSIONS

Hand exposure during the restoration of flow to thrombosed dialysis access grafts is relatively high and is greater for the right hand than for the left. The exposures are dependent on technical factors, most notably fluoroscopy times, not on patient- or graft-related factors.

Practice of ALARA in the pediatric interventional suite

As interventional procedures have become progressively more sophisticated and lengthy, the potential for high patient radiation dose has increased. Staff exposure arises from patient scatter, so steps to minimize patient dose will in turn reduce operator and staff dose. The practice of ALARA in an interventional radiology (IR) suite, therefore, requires careful attention to technical detail in order to reduce patient dose. The choice of imaging modality should minimize radiation when and where possible. In this paper practical steps are outlined to reduce patient dose. Further details are included that specifically reduce operator exposure. Challenges unique to pediatric intervention are reviewed. Reference is made to experience from modern pediatric interventional suites. Given the potential for high exposures, the practice of ALARA is a team responsibility. Various measures are outlined for consideration when implementing a quality assurance (QA) program for an IR service.

The use of extremity dosemeters in a hospital environment

A general overview is given on the use of extremity dosemeters, their calibration, the units and phantoms to be used. One of the major applications of extremity dosemeters is to monitor the personnel in a hospital environment. In nuclear medicine, brachytherapy and interventional radiology (IR) skin doses to hands and legs can be substantial. Here, we report on two studies that are presently being undertaken in Belgium. The first one tries to map the dose distribution on the hands, in function of the manipulation in nuclear medicine. Some preliminary results are also given from a nationwide survey study for patient and personnel doses during IR and cardiology. The radiologists' hands, legs and forehead are monitored during a whole range of procedures in different hospitals.

A study of the distribution of dose across the hands of interventional radiologists and cardiologists

The magnitude and distribution of doses across the hands of interventional radiologists and cardiologists have been studied. The aims were to determine the region of highest dose, investigate variations in dose distribution, and propose an effective method for dose monitoring. Doses have been measured using sets of up to 18 thermoluminescent dosemeters (TLDs) for 183 single procedures. Important factors influencing the dose to the hand are the type of procedure, particularly the access route, the X-ray equipment used, and the experience of the operator. Radiologists performing percutaneous procedures received the highest doses, because of the proximity of their hands to the X-ray tube. The majority of procedures involve a combination of twisting and prodding actions, and the relative proportions of each determine the parts of the fingers which receive a higher dose. For most interventional radiology and cardiology procedures the bases of the ring and little fingers receive the highest dose. However, during percutaneous procedures the tips of the middle and ring fingers could receive doses which were 20-30% higher than this. For radiologists and cardiologists with a mixed workload, monitoring using TLD rings located at the base of the little or the ring fingers on either hand should provide a reasonable estimate of dose to the most exposed area. Monitoring is recommended for operators who may receive over 50 mSv to their hands per year, and should be considered for operators carrying out therapeutic procedures involving patient dose-area products over 500 Gy cm2 per month.

Investigation of occupational radiation exposure during interventional cardiac catheterisations performed via radial artery

The purpose of this study was to determine the thyroid, sternum and hand radiation doses of radiologists who perform angiographies and angioplasties via the radial artery. Staff radiation dose was estimated for 21 cardiac interventional catheterisations. Thermoluminescence dosemeters (TLDs) were used to determine radiation dose for each procedure at the right and left wrist, at the sternum and the thyroid. A dose area product (DAP) meter was also attached to give a direct value in Gy cm2 for each procedure. Staff radiation doses varied between 34 and 235 microGy per procedure at the left wrist, 28 and 172 microGy at the right wrist, 16 and 106 microGy at the level of the thyroid and 16 and 154 microGy at the level of the sternum. The DAP values varied between 25 and 167 Gy cm2. Radiation doses in this study are comparable to those reported in previous studies. Moreover, good correlation was found between the DAP values and the occupational dose measured with TLDs.

Paediatric personnel extremity dose study

Concern has been expressed in paediatric radiology regarding the magnitude of the extremity dose received by attending personnel during routine fluoroscopic procedures and CT. Common procedures that may be of short duration in adults can be quite the opposite in paediatric patients. The extremities of attending personnel are more likely to be exposed to the primary beam and for a longer period of time owing to a variety of reasons such as assisting in the procedure or physically restraining the patient during the examination. During the period mid 1998 to mid 2000, two paediatric radiologists, four senior radiographers and two paediatric nurses were monitored using ring thermoluminescent dosemeters (TLDs). Each participant wore the ring TLD on either the left or right ring finger, depending on which hand the individual favoured. Left/right asymmetrical studies were not conducted, nor were records kept of whether an examination used a grid or gridless technique. Initial apprehension about higher paediatric fluoroscopic and CT extremity doses was dispelled as a result of this quantitative dosimetric study.

Using a sterile disposable protective surgical drape for reduction of radiation exposure to interventionalists

OBJECTIVE

The purpose of this paper is to show the effectiveness of a new radiation protection method designed to decrease the amount of scatter radiation received by practitioners performing procedures under fluoroscopic guidance.

MATERIALS AND METHODS

A sterile, disposable, lead-free surgical drape containing radiation protection material composed primarily of bismuth was evaluated for effectiveness in reducing radiation doses to health care personnel. Measurements of phantom scatter, patient scatter, skin entrance, and the effects of collimation, together with comparative monthly thermoluminescent dosimeter recordings, were taken to determine the effectiveness of X-ray beam attenuation using the bismuth drapes.

RESULTS

Scatter radiation to physicians, as measured by thermoluminescent dosimeters placed on each eye, the thyroid, and the wrist, was reduced by 12-fold for the eyes, 25-fold for the thyroid, and 29-fold for the hands when the radiation-attenuating surgical drape was used when compared with control studies performed with a standard nonattenuating surgical drape alone. Monthly thermoluminescent dosimeter measurements decreased fourfold in one physician. Using the protective drape reduced exposure to the assistant in each case to negligible levels. Skin entrance dose was not increased unless the protective drape was placed directly in the X-ray beam. An X-ray attenuation factor equivalent to 0.1 mm of lead with 8 x 8 cm collimation reduced the scatter rates from five- to ninefold despite a 30-40% increase in entrance exposure rate as the lead equivalence increased.

CONCLUSION

Depending on the procedure, the height of the practitioner, and the positioning of the radiation-attenuating surgical drape, use of this drape can substantially reduce the radiation dose to personnel with minimal or no additional radiation exposure to the patient.