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کاربرد نوع شرط:
- جایگاه : پژوهشی
- مجله: Iranian Journal of Medical Physics
- نوع مقاله: Journal Article
- کلمات کلیدی: Dose Volume Histogram,Tumor control probability,Normal tissue complication probability
- چکیده:
- چکیده انگلیسی: Introduction: The ultimate goal of radiation treatment planning is to yield a high tumor control probability (TCP) with a low normal tissue complication probability (NTCP). Historically dose volume histogram (DVH) with only volumetric dose distribution was utilized as a popular tool for plan evaluation hence present study aimed to compare the radiobiological effectiveness of the cobalt-60 (Co-60) gamma photon and 6MV X-rays of linear accelerators (Linac) in the radiotherapy of head and neck tumors.
Materials and Methods: TCP and NTCP were calculated using DVH through the BIOPLAN software developed by Sanchez-Nieto and Nahum . The treatment planning was performed for all the patients using both treatment modalities (i.e., Co-60 and 6 MV Linac). The TCP was also manually calculated using a mathematical formula proposed by Brenner’s et al.
Results: The average TCP calculated by the BIOPLAN for Co-60 and 6 MV X-rays were 44.6% and 60.8%, respectively. Furthermore, the average NTCPs obtained for the organ at risk, namely optic nerve, for Co-60 and 6 MV X-ray were 0.24 % and 0.03 %, respectively. Regarding the spinal cord, the average NTCPs for Co-60 gamma photon and 6 MV X-ray of Linac were 0.05 % and 0.002%, respectively.
Conclusion: As the findings of the present study indicated, Co-60 unit could provide comparable TCP along with minimal NTCP, compared to the high-cost technologies of Linac. The design of treatment plans based on the radiobiological parameters facilitated the judicious choice of physical parameters for the achievement of high TCP and low NTCP.- انتشار مقاله: 17-11-1395
- نویسندگان: Anoop Kumar Srivastava,MADHUP RASTOGI,SURENDRA PRASAD MISHRA
- مشاهده
- جایگاه : پژوهشی
- مجله: Asian Pacific Journal of Cancer Prevention
- نوع مقاله: Journal Article
- کلمات کلیدی: DNA damage,Q-PCR,Low Dose Radiation (LDR),DNA Lesions
- چکیده:
- چکیده انگلیسی: Background: Radiation causes oxidative lesions and strand breaks in DNA of exposed cells. Extended length
PCR is a reliable method for assessing DNA damage. Longer DNA strands with DNA damage are difficult to amplify
compared to smaller DNA strands by PCR. The present study was aimed to evaluate DNA damage caused by ionising
radiation exposure in therapeutic and diagnostic medicine. Materials and Methods: The study group comprised 50
cases with low dose single exposure (LDS), low dose multiple exposure (LDM) and low dose angiography (LDA)
which were compared with 25 high dose controls (HDC) and 25 controls with no exposure (NEC). Blood samples were
collected within 1 hour of radiation exposure. DNA was isolated using a kit based protocol, 50 ng aliquots of DNA
were used to amplify a long 13kbp DNA fragment of the β-actin gene by conventional PCR and band intensity was
then quantified. Relative amplification was calculated and damage was expressed in terms of lesions per kilobase (kbp)
by assuming a Poisson distribution. Result: Relative amplification was found to be 1.0, 0.87, 0.86, 0.72 and 0.69 with
NEC, LDS, LDM, LDA and HDC groups, respectively. Cases undergoing angiography as well as high dose controls
had high values, compared to NEC. The lesions/kbp calculated for LDS was 0.13, for LDM 0.15, for LDA 0.32 and
for HDC 0.37 suggesting a linear increase in quantity with increasing radiation dose. Conclusion: DNA damage, even
at low doses of radiation can be assessed by quantitative extra long PCR.- انتشار مقاله: 26-10-1396
- نویسندگان: Kainat Khan,Shikha Tewari,Madhup Rastogi,Gaurav Raj Agarwal,Surendra Prasad Mishra,Nuzhat Husain
- مشاهده