Cardiac catheterization and electro-physiological procedures involving X-rays fluoroscopy have been increasing at a fast pace in many countries. In addition now the cardiac CT is adding further the work load with ionizing radiation in many cardiology facilities.
Cardiac catheterization and electro-physiological procedures involving X-rays fluoroscopy have been increasing at a fast pace in many countries. In addition now the cardiac CT is adding further the work load with ionizing radiation in many cardiology facilities. This is creating the need for awareness about radiation protection (RP) among cardiologists. Unfortunately most cardiologists have rarely undergone formal training in RP and as a result there are situations of fear on one side and carelessness on other side. With proper knowledge both can be avoided and it is possible to work full life with ionizing radiations while avoiding radiation effects to self, other colleagues and to the patients.
On the issue of staff protection, it must be said that even in radiotherapy, where very high radiation doses are delivered to patients, the staff works either with shielded sources or at shielded locations. The radiation intensities in nuclear medicine are much lower than those from X ray machines and in radiology most staff work at console located away from the X ray source except interventional radiologist. An interventionalist may get a radiation dose in one day of work (say in 5 PCI procedures) in cath lab if proper RP is not followed, equivalent to what a staff may get in one year while taking about 100 radiographs each day. Thus interventionalist faces much higher level of radiation than most others. Lead apron or equivalent lead-free apron cuts down radiation by about 92 to 99% depending upon lead equivalence and energy of X rays falling on it. A thicker patient will need higher energy X rays and thus the same lead apron may stop only 95% of scattered X rays whereas it may stop 99% when a child is undergoing procedure. Lead glass screens and eye glass wears are very effective and can stop again 95-99% X rays. If eye protection is not used, there is risk of cataract in few years. The loss of hair in lower legs has been reported at part not covered by lead apron. A good lead apron, eye protection and shield for legs can make situation fairly safe.
The radiation doses to staff performing cardiac CT procedures are generally very small. In CT angiography procedures the major protection issue is the exposure to hands of the staff. If hand can be outside the primary beam, the radiation dose can fairly small.
For the sake of simplicity it may be said that the radiation dose to the patient in a PCI may be about 500 times than in a chest X ray. It is also reported that a case of radiation induced skin injury lands up in US courts almost every 6 weeks. The radiation risk to the patient is high in procedures that involve longer fluoroscopy time of the order of one hour, if the patient has high body mass (thicker chest) and if there are conditions that may lead to radiation sensitivity. Lack of knowledge about such injuries among interventionalist has resulted in patient going from place to place without getting diagnosed. In a number of cases severe radiation injuries have been reported that require skin grafting. Radiation injuries have also been reported when unnecessary body part, mainly the arm of the patient, falls in the path of the X ray beam. This also applies to the breast where every effort should be made to change the orientation of the beam to reduce the chance of breast falling in path of entrance port of the beam. Children undergoing interventional procedures run the risk of cancer in future years.
Attention to a number of procedural issues can help avoid injuries and reduce the radiation risk of cancer. It should be possible to perform cardiac cath procedure in pregnant woman, when so necessary, by adopting good technique. For details about radiation protection, readers are referred to IAEA website http://rpop.iaea.org.
The purpose of this presentation is to touch upon magnitude of the radiation exposure involved to patients and staff, radiation effects that have been documented among patients undergoing catheterization procedures and among interventionalists, effects that can be prevented and those where the probability can be minimized and ultimately how to work in a manner to avoid radiation effects to patients and staff even with large workload.