Infectious diseases are one of the leading causes of death among children under the age of 5 with 60% of those deaths preventable with prophylaxis. Vaccinations prove to be the most succesfull and effective public health tool of infectious dieases preventions. Poland first implemented a program of mandatory childhood vaccinations in 1960. The program is updated each year and provides parents with a clear schedule to follow. The program includes vaccinations against 12 diseases (tuberculosis, hepatitis B, rotaviral disease, diphtheria, pertussis, tetanus, Haemophilus influenzae, Streptococcus pneumoniae, poliomyelitis, measles, mumps and rubella) mandatory for all children and funded by the government. It also includes recommended vaccinations which costs are covered by a patient. Immunization rates are monitored nationwide and reported to the Chief Sanitary Inspector. With recent outbreaks of infectious diseases among young children the obligation lies on the government to provide childhood immunizations, and largely on the physicians to provide reliable education about infectious diseases in children and safety of vaccinations to the parents.

Ascites is a term that describes a pathological accumulation of fluid in a peritoneal cavity. It is generally a rare occurrence in a pediatric population and is most commonly associated with liver failure and cirrhosis. In that case, a diuretic treatment is usually implemented to relieve the ascites as it forms in the mechanism of water retention and water leakage from the portal venous system due to portal hypertension. It is important to note however that many other issues may cause ascites in children. Those require a catered approach suited to the pathomechanism of ascites formation in those underlying conditions. That is why a complex diagnostic process ought to be run in pediatric patients with ascites to correctly identify a condition causing it and provide the patient with adequate and thorough care.

Aim of the presented research was to develop an optical sensing system to investigate the demineralization process of the bones. Optical measurement techniques are widely used and increasingly adapted in biological and biomedical applications due to their non-destructive nature and safety. Optical examination of the bone condition could facilitate clinical trials and improve the safety of patients. The authors used a set of complementary methods: polarization-sensitive optical coherence tomography (PS-OCT) and Raman spectroscopy. To stimulate the process of demineralization and gradual removal of the hydroxyapatite, the test samples of chicken bones were placed into 10% acetic acid. Measurements were carried out in two series. The first one took two weeks with data acquired every day. In the second series, the measurements were made during one day at an hourly interval (after 1, 2, 3, 5, 7, 10, and 24 hours). Raman spectroscopy was used to evaluate the disappearance of the hydroxyapatite. The relation between the content of hydroxyapatite and images recorded using OCT was analyzed and discussed. Moreover, the polarization properties of the bones have been evaluated. Based on OCT images, the retardation angles of the bones have been calculated. This work presents a preliminary study on the mechanism of bone demineralization and confirms the potential of the applied optical methods.