A simple technique to reduce the generation of unwarranted X- rays

Valarmathy1*, Mahalakhmi2, Esthar Rani3

1ANS, Kauvery Hospital, Tennur, Trichy, Tamil Nadu

2Senior Scrub Nurse , Kauvery Hospital, Tennur, Trichy, Tamil Nadu

3Nursing Superintendent, Kauvery Hospital, Tennur, Trichy, Tamil Nadu

*Correspondence

Introduction 

The advent of endovascular surgery has brought immense benefit to the patients by reducing the morbidity of the procedure compared to open surgical procedures. However, it has also brought in a new and dangerous by-product with it: the radiation.

We all continue to receive radiation from Mother earth, though in very negligible amounts. Radiation when ionized causes damage to our body and the damage depends on the type and energy of the radiation. Radiation cannot be felt or seen; however, the amount of radiation we are getting exposed to can be measured.

Background  

The electromagnetic spectrum comprises of 2 types of radiation: ionizing and non-ionizing. Cosmic, gamma and X-rays constitute the ionizing component, the group which we should be wary of.

Height can be measured in millimeters, centimeters etc. Similarly, the unit of absorbed radiation dose is Sievert (Sv). The radiation measured is in millisievert (one-thousandth of Sv). One chest X-ray will generate around 0.2 mSv of radiation dose. On average we receive around 3 mSv a year from all our natural resources.

Radiation during diagnostic or therapeutic interventions poses multiple hazards to the operator and the attending staff in innumerable ways: eyes, thyroid, gonads and other body organs. The general concept is to avoid exposure to the ionizing radiation as much as possible. Multiple ways have been devised to decrease the exposure to radiation like:

Traditional mechanical protection methods

  • Lead aprons
  • Thyroid collar
  • Eye wear
  • Leg protection sleeves
  • Lead shield (to protect from the X-rays generated from the C-Arm)

Other methods

  • Staying away from the direct field of X-rays
  • Limiting the on and off the X-ray beam (generation of the beam)

Generation of the x ray beam and its control

During the angiographic procedure (Catheterization laboratory or in the operation theatre using mobile C arms), the generation of the X-rays is usually performed by the technician. This usually contributes to a slight excess in the total amount of dose generated rather than when performed by the operating surgeon.

The reasons are:

  • The exact spot at which the table must be positioned, though when conveyed by the surgeon to the technician, it doesn’t happen all the time.
  • The radiation is produced in succession to conform the spot of interest
  • The injection of the contrast and the generation of the X-ray: the timing when misunderstood can generate unnecessary X-rays

Ways to limit the unnecessary generation of x-rays 

The control for generation of X-rays and the toggle for moving the table must rest with the surgeon. In the angiograms of the lower limb, the position of the X-ray beam generator must be positioned at appropriate places to view the following anatomical regions:

  • Mid femur
  • Above Knee joint
  • Below knee joint
  • Mid leg
  • Lower leg, ankle and foot

These segments of the lower limb are identified by placing different surgical instruments by the side of the lower limb (Allis, Babcock, curved and straight hemostatic forceps; small and medium in size) [Fig 1]

Fig (1): Various surgical instruments are placed at appropriate distances in the lower limb; the X ray beam is usually generated between the two instruments; the top instrument corresponds to the mid-thigh segment

The placement of the instruments helps to recognize the parts of the lower limb artery to be imaged. The segment of the artery between the two instruments is identified, studied and intervened if needed. Moreover, the preoperative Magnetic resonance Angiogram gives a roadmap about the lesions to be imaged and intervened in the operation theatre.

The placement of the instruments gives an approximate localization of the artery and its lesions. This step reduces the unnecessary movements of the table and the radiation generated. i.e., the beam is positioned between the two instruments.

However, in order to further reduce the amount of radiation generated, the following methods have been tested and verified in the operation theatre:

  • The instruments are placed at designated places as stated above.
  • The angiogram is performed.
  • The lesions in the artery which need to be treated are identified between the two instruments.
  • The laser light beam is switched on [Fig 2]

Fig (2): Surgical instruments placed at appropriate places; Laser beam intersection has been marked as “X”; it corresponds to above knee joint in the above diagram)

  • The intersection of the two laser light beams are marked (in the form of “X”) on surgical drape with the surgical marker pen. (Fig 3)

Fig (3): “X” mark corresponds to mid leg in the above picture

  • The site of “X” is the site where the X-ray beam generator must be positioned in subsequent image acquisition. (Fig 4) This reduces the unnecessary X-ray generation to relocate the sites for diagnosis and therapeutic purposes

Fig (4): the “X” mark corresponds to the above ankle region

Trying to locate the exact sites for intervention can lead to unnecessary X-ray generation if the dongle is operated by the Cath lab technician. Even if the dongle is operated by the surgeon, it can still lead to minor amounts of unwarranted X-rays if the exact site is not delineated. The amounts though small, when constantly generated over a period can seriously harm the operator and other personnel involved in the procedure.

Conclusion

X rays are to be generated and utilized in the least possible manner as they pose biological hazards in the short and long term. Multiple methods have been developed to reduce exposure from ionizing radiation. The position of the X-ray beam generator that must be operated by the surgeon is the vital step in reducing unwarranted radiation. This can be further reduced by making simple surgical marks (“X”) on the drape at the exact sites of interest which helps to further reduce the small yet unwarranted doses of radiation.

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