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Complete blood counts were evaluated in 30 human blood samples 22 males and 18 females. Whole blood samples were irradiated by the doses ranged between 10-41µSv/hr by radium-226, and at a different time of exposure. CR-39 NTDs and digital radiation dosimeter (RAM DA3-2000) were used to estimate an incident alpha particle density on the blood samples and an incident radiation dose, respectively.
The results show that the range of alpha particle energy (1-5MeV) in blood sample and surface of CR-39 NTDs varies exponentially depended on the restricted energy loss. The irradiation comparative study between CR-39NTDs and the blood samples, thus, considered as a new technique for in-vitro study in hematology.
Changes of blood components (after irradiation /before irradiation) occurred, and time of irradiation influential blood samples in this study were 6 minutes for the main blood components relatively. The change in RBC was so many little, so it is less effective than other blood components.
On the other hand, the most changes in the blood contents are beginning from low radiation dose (10.38-13.41µSv/hr). For the doses (13.41 - 21.77) µSv/hr, PLT counts increase rapidly and adversely with the RBC and WBC, due to chromosome aberration. PLT was reduced rapidly in the high dose (42.1 µSv.hr) do make a thrombocytopenia, opposite of it, WBC was increased too rapidly, an indication for the cancer, the cause due to the increase of the alpha particle dose. Generally, our results were in agreement with the essential of blood content and the phenomena of biological radiation interaction.
PACS: 23.60.+e ; 34.50.Bw ; 29.40.Wk; 87.19.xj ; 87.53.Bn ; 87.56.B; 87.90.+y
Key words: Human blood; CR-39 NTDs; Radium-226; Low radiation dose; Invitro study
Radiation is toxic to the human body, and increased levels can cause injury to tissue systems from free radical damage. Exposure can be acute or chronic, and symptom severity depends on many factors like total dose, dose rate, distribution of dose and the susceptibility of the patient to the radiation. Tissue systems with greater rates of cell division, such as the hematopoietic and gastrointestinal systems, typically fare worse as the necessary cell turnover is interrupted by widespread cell death. Platelet levels at the time of diagnosis could be a useful prognostic factor in lung cancer [1-3].
In general, high linear energy transfer (LET) radiation (alpha particles and fission fragments) is more efficient in inducing biological damage than low LET radiation (gamma and X-rays, Î²-particles), because most of the incident energy will be deposited within a short distance causing dense ionization in the trajectory [2,4].
Hematology studies in the field of radiation (long-term exposure) have an active role to estimate exposure to ionizing radiation, it due to increases the number of chromosome aberrations in human blood lymphocytes. This increase mainly reflects the last year of exposure, owing to repair mechanism, and limit the usefulness of this parameter as a marker of long-term exposure [5, 6].
The main sources of radiation in the soil are 238U and 232Th, these sources can result in different diseases, of which cancers are quite common, especially lung and blood (leukemia). Leukemia concludes from infection in the blood parameters; Weight Blood Cont (WBC), Red Blood Count (RBC) and the Platelet Count (PLT), see Fig. 1. High WBC can be a sign of infection, and it is increasing in certain types of leukemia. Low white counts can be a sign of bone marrow diseases or an enlarged spleen. High hemoglobin (Hgb) can occur due to lung disease, living at high altitude or excessive bone marrow production of blood cells. Decrease in the number of platelets in the blood due to a thrombocytopenia, which can result in poor blood clotting. Thrombocytopenia is usually defined as less than 150,000 platelets per cubic millimeter of blood .
Lung cancer (LC) is now the leading cause of cancer mortality in the world. Therefore, it would be useful to identify prognostic factors to determine a patient outcome . The objective of this study is to evaluate the usefulness of platelet counts at the time of diagnosis as a prognostic factor, and estimate optimum dose /time of irradiation for in vitro study on blood parameter compliments. In the present work, low radiation doses of radium 226Rn (5 µCi) is used for study the hematological effects of low radiation, using CR-39 Nuclear Track Detectors (NTDs) techniques, more details about track formation in CR-39 and effect of storage on efficiency of CR-39 are mentioned in references [8,9 ]. Complete blood count (CBC) calculates for the blood samples before and after irradiation, and for different dose and irradiation times.
2. Research Methodologies
2.1 Blood Sample Collection
Blood samples (approximately 3 ml) are collected by venipuncture into heparinized syringes for 25 males and female volunteers (20- 43 years old), using established blood-borne pathogen/biohazard safety protocols. This study was conducted with the cooperation of the wellness center of Universiti Sains Malaysia (USM). Primary test for the whole blood samples is done, and then it has been irradiated with a different radiation dose (226Ra) and time of irradiation. The period for the blood tests (before and after irradiation) is less than 3 hours.
2.2 Irradiation Procedures
Blood samples are exposed to the source of Radium in the Biophysics laboratory / School of Physics /USM. Depending on the alpha particle range and distracted energy loss of it, a new design of an irradiation system was fabricated and used in this research, as shown in Fig.2.
Irradiation dose and time of irradiation vary from 10 to 41 µSv/hr and 2 to 10 minutes, respectively, depending on the alpha particle range. For exposures to the radiation dose from radium, whole blood samples were transported at a temperature of (28±2 C0) to the radiation collimator system, as shown in Fig.2.
The range of alpha particle in the blood and CR-39NTDs has been taken into account in consideration to the irradiation system, using the SRIM 2010 program . Irradiation was done at room temperature in a controlled area for both types of radiation. The irradiation of whole blood samples was performed immediately 2 hours after the blood samples were drowned.
2.3 Etching and scanning process of CR-39 NTDs
The etching's systems consist on etch track detectors at 6 Normality of NaOH at 70Co, distiller water and water bath "GOTECH TESTING MACHINES INC" model GT-7039-M, 220 volt, 50Hz. For scanning process, the etched tracks were observed using an optical microscope fitted with a magnification of 50 X to 1000X. The microscope image was viewed with a high-quality monochrome charge coupled device (CCD) TV camera, which is connected to a PC-based image analyzer, as shown in Fig.3.
3 Results and Discussion
Table 1 shows the range of alpha particles (1-5 MeV) in the whole blood (density of blood samples = 1.06g/cm3) and the CR-39 NTD (density of CR-39 = 1.31 g/cm3). The variation of the range of alpha particle was depended on the target density (blood or CR-39NTD), and this is depended on the restricted energy loss, as shown in figures 4, 5. High LET radiation of alpha particles, which are emitted from 226Ra, is more efficient in inducing biological damage because all the energy is deposited within a short distance, causing dense ionization in the trajectory. This is making damage on the structure cells. Here, blood cancer estimated to grow and make tumor cancer. So, the irradiation combination (comparative study) between CR-39NTDs and the blood samples is a new method for in-vitro study in hematology.
Relationship between equivalent radiation doses (µSv/hr), the alpha particle density (track/cm2.1minute) which are emitted from 226Ra and registration on CR-39NTD and alpha particle energy (MeV) are listed in Table 2. One observed that the relation between them is not linear; this is due to that the average dose is not only from alpha particles, and from the recorded dose by the digital dosimeters represented radiation does from alpha, beta and gamma, which are emitted from 226Ra. The relationships between alpha particle energy and alpha track registration with the average incident radiation dose were logarithmic and exponential, respectively, and as shown in Fig. 6. This is essentially in agreement with the decay of radium and the registration nature of the equipments [11, 12]. Average radiation doses which are recorded by RAMDA3-200 represent the gamma, beta and alpha radiation dose, but the track density which is registered by CR-39NTDs represents the tracks for alpha particles. Therefore, the relationships (logarithmic and exponential) were different. So, for invitro and in-vivo studies of radium, these relations should be taken into account.
Complete blood counts (CBC) for the selected human blood samples before and after irradiation with (41.2 µSv/hr) are listed in Table 3. One observed that the irradiation dose affected most of the blood parameters, especially on the platelet count cell (PLT), depending on time of irradiation. In Fig.7, one observed that the change of blood components before and after irradiation has been done with different ratios; this was depended on the type of blood component. Time of irradiation influential blood samples in this study were 6 minutes for the main blood components (PLT, WBC and RBC) relatively, this means that the effective radiation dose depends on the exposure time depending on the gross alpha energy. The change in RBC was so little as shown in Fig.7. (red color), because red blood cell hardness to radiation, so it is less effective than other blood components. Meanwhile, we note that the effects occurring in red blood cells to be adversely effects of white blood cells, and platelets, this is in agreement with the essential of the hematologist and radiation casualties .
On the other hand, Complete blood counts (CBC) for the selected human blood samples before and after irradiation with a different radiation dose for 6 minutes is listed in Table 4. From Table 4 and Fig.8, one observed that the main changes in the blood contents are beginning from low radiation dose (10.38-13.41 µSv/hr), and then the effects reach to be stable for RBC. From the dose 13.41 µSv/hr to 21.77 µSv/hr, PLT counts increase rapidly and adversely with the RBC and WBC due to chromosome aberration. So, cells with residual chromosomal damage were used as a biological endpoint for determining whole blood effects of low doses of radiation. PLT was reduced rapidly in the high dose (42.1µSv.hr) due make a thrombocytopenia, opposite of it; WBC was increased too rapidly, making an indication for the cancer. The reason of this phenomenon (blood radiation by 226Ra) in the high dose is due to high dose of alpha particle, this is making the greatest damage to the blood cells, because the alpha particles are heavy ions. Therefore, the alpha particles will be losing most of their energy at a short distance in their trajectory for irradiation. This makes ionization for the atoms of blood cell by the method of atomic displacements. The results are in agreement with the essential of blood content and the phenomena of biological radiation interaction [12, 14].
The distributional methods for alpha particles and radiation dose on the surface of CR-39NTDs and the whole human blood samples have been significantly improved. The range of alpha particle in CR-39NTDs was less than the range of it in the human blood samples, depending on their density and restricted energy loss. Comparative study between CR-39NTDs and the human blood samples was a new technique for in-vitro studies of the blood ionization, especially to estimate ionization of alpha particle. Therefore, CR-39 NTDs considered as the most suitable nuclear detector to get alpha particle density deposited on the blood surface.
One concluded that the effects occurring in red blood cells to be adversely effects of white blood cells and platelets, because the red blood cells are hardness for the radiation, so we believe red blood cells less effective than other blood components. Meanwhile, time of irradiation influential blood samples in this study were 6 minutes, this means that the effective radiation dose depends on the exposure time and on the gross alpha energy. This study authenticated that the studies conducted outside the body are necessary to assess the effective dose in the body of the object, as the changes that appear in the chromosomes lead to the occurrence of different cancers.