Those who have children or have visited babies in maternity wards must have experienced the strange sight of their sometimes yellowish skin, mucous membranes and whites of the eyes. This problem, known as physiologic jaundice or neonatal hyperbilirubinemia usually arises in the second or third day after birth and is relatively common, affecting 60% to 80% of newborns worldwide, depending on the location. The problem is related to the immaturity of the liver, incapable of metabolizing bilirubin, a normal, yellowish pigment generated through the metabolization of red blood cells. The main therapy used to treat physiologic jaundice, which normally has no significant consequences provided it is appropriately treated, is phototherapy (light baths). This requires that the newborn be exposed to light from fluorescent, halogen or incandescent bulbs, or to blue light from light emitting diodes (LEDs).
The efficiency of the treatment is directly proportional to the amount of irradiation upon the baby and the area of its body surface exposed to this radiation. The control and monitoring of this light upon newborn babies was studied by researchers from the Physics Department at the Federal University of Ouro Preto (UFOP). The result was the development of a radiation dosimeter made out of luminescent polymeric material. This device enables fine tuning and detailed monitoring of the light dose received by babies during this treatment. A patent request to use these polymers for the identification and quantification of non-ionizing radiation was deposited by the group in January 2007. Non-ionizing radiation is that which does not have the energy to emit electrons of the atoms or molecules with which it interacts.
The device is still in the prototype stage, but according to its inventors, it is ready to take on a commercial format. Its core element is a glass ampoule filled with a solution of luminescent polymers available in the market and known as MEH-PPV. The device works on the basis of the solution changing color as a result of the amount of time it was exposed to the radiation. When it is light sensitized, the solution’s color can range from red to colorless, going through orange, yellow, pale yellow, and so on. “The device should be placed next to the baby and indicates the amount of radiation received based on a simple color change”, explains physicist and UFOP professor Rodrigo Fernando Bianchi, who led the new technology’s development. The reading is qualitative, based on the change in the solution colors, or quantitative, using an electrical circuit comprised of a LED and photodetectors that measure the solution’s color change and indicate on a digital panel the radiation dose that the polymers absorbed. “Easy reading eliminates the need for complex and lengthy training programs for healthcare professionals to be able to use the equipment”, explains the researcher. To ensure better control and monitoring of the radiation, a set of five ampoules, in a plastic blister package, should be placed next to the newborn child. The researchers are already working on the creation of polymeric dosimeters that are like self-adhesive stamps, which could be used over nappies or on any part of the baby’s body.
Even though physiological jaundice is an easily controlled condition, it requires attention because certain problems can arise during treatment, generating false diagnoses, among other things. The chief concern focuses on the inefficiency of the sources of radiation used in maternity wards, because the lamps of the phototherapy equipment may be off spec, for instance. The distance between the source of lighting and the patient, and the positioning of the newborn during treatment may also fail to be ideal. Such factors can cause a lower radiation absorption rate, leading the treatment to be ineffective and causing severe health problems.
The increased concentration of bilirubin in newborns’ blood is extremely toxic for the nervous system and may cause irreversible neurological damage and even the baby’s death. The treatment’s main aim is to prevent bilirubin encephalopathy, also known as kernicterus. What the group from Ouro Preto proposes is that together with a bilirubin blood serum concentration test, delivered to the pediatrician, who evaluates the pigment content in the blood of newborns, an expert opinion be attached showing the dose of radiation absorbed by the newborn. “This way, pediatricians would be sure that that babies actually got the prescribed radiation for the condition’s treatment”, says Bianchi, who is the coordinator of UFOP’s Laboratory of Polymers and of Materials with Electronic Properties.
New developments in the field of dosimetry have become increasingly consistent n the last few years. The ideal device, according to doctoral candidate Cláudia Karina Barbosa de Vasconcelos, one of the team members, should be capable of measuring the dose emitted by a radiation source with exactness, precision, detection limits and ease of operation, among other parameters. Certain technologies, such as radiation sensors, are already used to monitor the dose of light that reaches the body surface of the babies submitted to phototherapic treatment. However, according to Bianchi, none of them is similar to the polymer dosimeter produced by his team. “As far as we know, there are no similar devices”, he says. According to the researcher, the problem of the commercially available sensors is that they need to be calibrated constantly and none of them produces a simple reading of the radiation dose.
Some of the other advantages of the prototype from the state of Minas Gerais are that it is easy to manufacture and handle, and is also inexpensive to produce. On a laboratory scale, each polymer ampoule costs less than R$0.10, whereas the blister pack costs less than R$0.40. The introduction of the product in the market place, Bianchi believes, is only a matter of time. “We’re working with two possibilities. The first is submitting a project to FAPESP’s PIPE (Innovative Research at Small Firms) program. This would be coordinated by the students involved in the development, who would move to São Paulo in order to set up a company. The second option involves the possibility of transferring the technology to firms interested in developing, manufacturing and marketing the product,” says the UFOP researcher. “We’re already talking with a potentially interested party, but we haven’t reached a conclusion”, he states. To develop the dosimeter, the group was funded by CNPq, Brazil’s National Scientific and Technological Development Council ,which is part of the Ministry of Science and Technology, and by Fapemig, the Minas Gerais State Foundation for Research Aid.
Dosimeter for phototherapy; Modality National Nanotechnology Program – Young Researchers, Polymer Materials Multidisciplinary Institute – Millenium Institute and Open Public Notice; Coordinator
Rodrigo Fernando Bianchi – UFOP; Investment R$ 170,000.00 (CNPq), R$ 35,000.00 (MST) and R$ 90,636.00 (Fapemig)