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| DC Field | Value | Language |
|---|---|---|
| dc.contributor.advisor | Ismail Bahari, Dr. | |
| dc.contributor.author | Abubaker Ali Y. Alghoul (P50313) | |
| dc.date.accessioned | 2023-10-13T09:31:43Z | - |
| dc.date.available | 2023-10-13T09:31:43Z | - |
| dc.date.issued | 2013 | |
| dc.identifier.other | ukmvital:71458 | |
| dc.identifier.uri | https://ptsldigital.ukm.my/jspui/handle/123456789/499386 | - |
| dc.description | It is well established that the high-LET radiation from charged particles will damage the biological systems. However the dependence of the biological damage on the physical quality parameters of these radiations is still not clearly established. Estimating this relationship is very difficult particularly at lower dose region even though linear extrapolation method is universally employed as a preferable technique to predict the biological effectiveness. As this method is straightforward, many factors need to be considered before quantifying the biological effects properly. The research was directed mainly to identify the appropriate physical parameters that are capable to quantify the biological effectiveness of the high-LET radiations at lower doses region. This research also explained the critical mechanism as well as the biological risk coefficients of the biological effectiveness for the high-LET radiations. The research was conducted by analysing the available secondary data from relevant database of radiation biology for specific biological end-points which are cell inactivation, dicentric chromosomal aberration, cell mutation and oncogenic transformation based on the varies physical parameters which are radiation energy, linear energy transfer, linear primary ionization, radiation mean free path and effective charge of charged particles. Statistical analyses were performed by employing the Sigma plot version nine programme. The results show that the biological effectiveness of the high-LET radiations at low dose region is better to be quantified in terms of the effect cross-section and the linear primary ionization for each investigated biological end-point. The spacing of the double strands of the DNA molecules and the spacing of the ionization events are actually influence the mechanism of the biological effectiveness of the high-LET radiations. The biological risk coefficients are determined for each investigated biological end-point based on two techniques: The first technique is based on the correlation obtained between the radio-sensitivity and the radiation mean free path. While the second technique is based on the correlation obtained between the effect cross-section and the radiation mean free path. The risk coefficient of cell inactivation is analysed for 1H, 2H, 3He and 4He particles while for the dicentric chromosomal aberration and cell mutation is based on 1H. The risk coefficient for oncogenic transformation was analysed by using various heavy charged particles. The biological risk coefficient values based on the first technique of the cell inactivation produced by 1H, 2H, 3He and 4He particles are 8%, 39%, 18% and 66% respectively. The biological risk coefficients for dicentric chromosomal aberration and cell mutation produced by 1H particles are equal to 0.92% and 22% respectively. In the second technique the risk coefficients of cell inactivation produced by 1H, 2H, 3He and 4He particles are 8%, 34%, 18% and 63% respectively. The risk coefficients for dicentric chromosomal aberration and the cell mutation produced by 1H particles are 1% and 39% respectively. The risk factor for oncogenic transformation produced by heavy charged particles is equal to 21%. The risk coefficients for the charged particles increase with the size of the charged particle in sequence 1H < 2H > 3He < 4He. The higher value of the biological risk coefficient means the higher the probability of the radiation effectiveness and is in agreement with the radiation protection principle. In conclusion, the linear primary ionization and the radiation mean free path are better alternatives to quantify the biological effectiveness of the high-LET radiations at the lower doses region.,Ph.D | |
| dc.language.iso | eng | |
| dc.publisher | UKM, Bangi | |
| dc.relation | Faculty of Science and Technology / Fakulti Sains dan Teknologi | |
| dc.rights | UKM | |
| dc.subject | Radiations | |
| dc.subject | Radiation dosimetry | |
| dc.title | An alternative approach for quantification of biological effectiveness of high-LET radiations at lower doses region | |
| dc.type | Theses | |
| dc.format.pages | 165 | |
| dc.identifier.callno | QC795.32.R3.A436 2013 | |
| dc.identifier.barcode | 000594 | |
| Appears in Collections: | Faculty of Science and Technology / Fakulti Sains dan Teknologi | |
Files in This Item:
| File | Description | Size | Format | |
|---|---|---|---|---|
| ukmvital_71458+Source01+Source010.PDF Restricted Access | 3.98 MB | Adobe PDF |  View/Open |
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