Lead Armoring

In order to minimize the radiation beams emitted by radiology rooms used in cancer treatments, these rooms are covered with lead. In other words, it is very important to reduce the harmful effects of radiation to an acceptable level. This is a regulation that should be made for the health of both patients and employees. The fact that lead is a dense metal is among the reasons why it is not permeable to radiation rays. Therefore, reducing the effects of radiation with lead coating is one of the best known methods. In fact, lead shielding, which can also be considered as a security measure, is very important especially for the healthcare field. It is necessary to carefully measure all surfaces and floors of radiation rooms and to determine where the radiation sources are. In this way, a more effective armoring can be made. Lead shielding made using quality lead element will not allow leakage, thus preventing possible problems. In this way, radiation chambers can be used for a long time without any problems.

What Materials Are Used in Radiation Shielding?

Armor materials can be divided into 3 types. When choosing among these, the type of radiation to be shielded is considered. E.g; It is sufficient to shield alpha and beta radiations with a light aluminum material. Gamma rays, on the other hand, are 100 times higher than betas and 1000 blacks higher than alphas, depending on the energy of the source. Radiations with such high penetration can be covered with materials with intense height and high atomic number. Lead is the material with the highest atomic number among radiation shielding materials in this area. The higher the density of the armor material, the better it shields X and gamma rays. Apart from this, concrete can also be considered as a low-cost, easy and good armoring material. However, it should be noted that it has a high density like lead. E.g; This feature can be achieved by adding high-density aggregates to concrete mixes. With its high density feature, barite aggregate adds an effective shielding opportunity to concrete mixtures. Concrete larger than 2.8 t/m3 is called heavy concrete. Special aggregates such as barite, limonite, magnetite are used in the production of heavy concrete. The unit weights of these industrial wastes used should be large. With these features, heavy concretes are separated from normal concretes. It is light in terms of mixing and hydration water in heavy concrete mixtures that can be used as a radiation shield; There are heavy elements in terms of aggregate. Barite is the most widely used heavy aggregate. Absorption capacity varies depending on heavy barite concrete, barite aggregate ratio and unit weight of concrete.

Heavy concretes used for armoring in radiology have more protective properties than normal concretes. While determining how permeable it is to radiation, the unit weight of the concrete and the weight of the shield are taken into account. The greater the unit mass of the concrete, the greater its thermal conductivity. Materials with high thermal conductivity are not resistant to fire. The following comparison is made between heavy concretes with barite aggregates and conventional concretes:

• Heavy weights with barite aggregates are more durable than normal concretes in terms of wear.

• In terms of weight, heavy weights with barite aggregates are 50% larger than normal concretes.

• In terms of freezing and thawing, heavy aggregates with barite are less durable than normal concrete.

How is Radiation Shielding Calculated?

Many factors need to be determined when calculating radiation shielding. These are given below:

• Type of radiation source

• The location of radiation and its energy dependence

• Distribution by time

• The interaction mechanisms of radiation with matter

• Secondary radiation sources that arise after radiation and matter interact

Different methods can be used when calculating radiation shielding. Examples are deterministic methods, scholastic methods, and standard experimental and computational methods. Among these calculation methods, the Monte Carlo method has come to the fore and it is a scholastic method. In the Monte Carlo method, calculations are made using the functions of probability distributions of physical events. In this method, the interaction distance of the neutron is used as the probability distribution function. Two, three, or none of the particles may fail to exit the system. Using the interaction mechanisms of the system, these simulations are repeated and the mean value is found with a certain margin of error. If the standard material, geometry or application is out of the way, the Monte Carlo method is used. The Monte Carlo method is frequently used when calculating radiology room shielding.

Armor thickness is calculated based on:

• primary barrier

• Barrier thickness

• pass factor

• Total pass factor

• Neutron dose equivalent

• Total dose equivalent

• secondary barrier

• Leakage pass factor

While shielding the radiology room to protect from radiation in radiology, the coating thicknesses are determined according to the location of the device in the room. Also, not all walls have to be of equal thickness. When determining wall thicknesses, primary beam direction, field clearance and distance to the wall should be considered. In addition, the distance to the surrounding rooms and their usage conditions should also be considered. For radiation protection in brachytherapy, the room should be kept locked when not in use. The patient should be alone in the armored room while receiving treatment, while the staff should watch from a room with camera and sound. In addition, there must be a field dosimeter at the entrance of the room.

What Doses Are Used in Radiation Shielding?

Certain dosages are allowed for radiation protection when performing operations such as lead shielding in the X-ray room. The maximum dose that a person can take into his body has been determined as 500 mSv. This figure, which was first determined in 1931, has now decreased to 50 mSv per year. The annual dose limit is determined by radiation officers who are members of the institution in a way that does not harm human health. At the same time, this dose should comply with international standards. The amount of dose taken from internal and external irradiation during the year represents the total annual dose. People are not allowed to be exposed to more than these specified doses. In addition, these doses do not include doses due to medical irradiation and natural radiation. Below are the maximum allowable annual radiation doses for staff and patients:

• The annual effective dose is a maximum of 20 mSv for the attendant and 1 mSv for patients.

• The annual equivalent dose is a maximum of 150 mSv for the eye of staff and 15 mSv for patients.

• The annual equivalent dose is a maximum of 500 mSv for the skin of staff and 50 mSv for patients.

• The annual equivalent dose is a maximum of 500 mSv for the arm and leg of the staff and 50 mSv for the patients.

Since the harmful effects of radiation can cause very important health problems, care should be taken to keep this dose at the minimum level rather than staying below the allowable dose. For this, every precaution must be taken. Lead shielding of imaging rooms is an example of this. Lead shielding should be done in the radiology rooms of the hospitals and the exposure of patients and staff to this effect should be minimized. For radiation shielding, the most suitable one for the room should be chosen among materials such as lead and concrete. If it is suitable for the room, lead, which is the most effective material in armoring, should be preferred as an armoring material. In addition, quality materials should be used. X-ray room lead shielding price is quite affordable considering the health benefits it offers. This shielding process must be carried out in every radiation room. There are armoring companies working specifically for this. To get radiation shielding service, you can choose among professional and quality companies and minimize the harmful effects of radiation.