|
|
 |
Search published articles |
 |
|
Showing 42 results for Lung Cancer
Dr. M. Rafique, N. Manzoo, S. Rahman, S.u. Rahman, M.u. Rajput, Matiullah, Volume 10, Issue 1 (6-2012)
Abstract
Background: Several epidemiological studies
conducted on underground miner’s show that
exposure to elevated levels of radioactive radon gas
is expected to increase the risk of lung cancer.
Relative risk of lung cancer is almost linear with
radon exposure. Elevated concentrations of radon are
not only reported within mines but also for closed
indoor environment of general public houses.
Measurements of radon play a serious role in
scrutinizing public health and safety in homes.
Materials and Methods: Indoor radon measurements
were taken over a period of year, using CR-39
detectors. Measured indoor radon concentrations,
was converted in to excess relative risk (ERR) factors
by using the risk model reported in the Biological
Effects of Ionizing Radiation (BEIR VI) report. ERR was
calculated for age groups of 35 and 55 years. A
careful selection of occupancy factor based on
interviews with house occupants has been made.
Results: Using this local occupancy factor, average
excess lung cancer risk for the age group of 35 and
54 y peoples was found to 0.51±0.03 and
0.42±0.03. Similarly average values of ERR for local
occupancy factor with ages 35 and 55 years was
found as 0.59±0.03 and 0.45±0.03. Conclusion: The
overall average excess lung cancer risk for the
studied area was 0.46±0.03. The study suggested
that United State Environmental Protection Agency
(US EPA) occupancy factor gave a higher excess lung
cancer risk as compared with the local occupancy
factor used for studied areas. The ERR due to indoor
radon is within the standard limits and does not pose
any serious threat to the occupants of the houses
under investigation. Iran. J. Radiat. Res., 2012 10(1):
19‐29
Y.j. Park, Dr. W.s. Yoon, J.a. Lee, N.k. Lee, S. Lee, D.s. Yang, C.y. Kim, J.h. Kim, Volume 13, Issue 3 (7-2015)
Abstract
Background: To determine which radiotherapy parameters are associated with the tumor response of locally advanced non-small cell lung cancer (NSCLC) patients undergoing concurrent chemoradiotherapy. Materials and Methods: Thirty one patients with IIIA/IIIB NSCLC underwent chemoradiotherapy with a median dose of 63 Gy. On our actual treatments, we made radiotherapy planning to cover the planning target volume (PTV) with 95% of the prescribed dose, and checked the second CT simulation when a cumulative dose was about 36 Gy. For this study, each PTV of primary tumor was re-defined with even margins from the gross target volume (GTV), and the actual plan overlaid the re-defined PTV. The correlations between the tumor response rate during chemoradiotherapy and after chemoradiotherapy, and the dose distribution parameters (D95, V95, mean tumor dose and homogeneity index), total dose and GTV, were evaluated. Results: Median overall survival was 15.5 months and the two-year survival 42.3%. At first recurrence, radiation-field recurrence, distant metastases and simultaneous recurrence were developed in 35.5%, 41.9% and 9.7% of the cases, respectively. The dose distribution parameters were generally favorable and were not related with tumor response rate. The tumor response rate after chemoradiotherapy was correlated with the residual GTV at second simulation (&gamma=-0.627, p<0.001) and the tumor response rate during chemoradiotherapy (&gamma=0.541, p=0.003). Conclusion: Minimal correlation was found between the dose distribution parameters that were over the minimal dose requirement and tumor response in NSCLC with concurrent chemoradiotherapy. The small residual volume during chemoradiotherapy could indicate good tumor response after chemoradiotherapy.
Dr. H. Al Zabadi, K. Mallah, G. Saffarini, Volume 13, Issue 3 (7-2015)
Abstract
Background: Many public health agencies rank residential radon exposure as the second leading cause of lung cancer after cigarette smoking. It has been shown that the risk coefficient for lung cancer is higher for children than that for adults. Therefore, indoor radon measurements were carried out in the elementary schools of Tulkarem province, West Bank, Palestine. Materials and Methods: Two hundred and thirty solid state nuclear track detectors (SSNTDs) type CR-39 were distributed in the classrooms of 20 elementary schools in Tulkarem province area. About thirty of them were used for quality assurance purposes. The CR-39 detectors were exposed in the schools for three months during the school summer holiday from May 2012 to August 2012 and then collected and etched in Sodium Hydroxide (NaOH) 6.25 N solution at 75 °C for 6 h. The tracks were counted manually at the digital microscope. Results: The indoor radon levels were generally low, ranging from 3.48 to 210.51 Bq/m3 (Becquerel per cubic meter), with a mean radon concentration (mean±SE standard error) of 40.42± 2.49 Bq/m3. The average annual radon effective dose was assessed to be (mean±SE) 0.17 ± 0.01 mSv/y (milliSievert per year) while the excess lifetime lung cancer risk was approximately 0.09%. The results obtained indicate that the indoor radon concentration was significantly affected by the floor level of the classroom (negatively correlated) and the school building age (positively correlated). Conclusion: The radon concentration and the resulting dose in the schools were within the reference levels of the International Commission on Radiological Protection (ICRP). Better ventilation is recommended to decrease the risk to the minimum.
B. Li, S.h. Chen, Dr. H.j. Lu, Y. Tan, Volume 14, Issue 3 (7-2016)
Abstract
Background: To investigate the expression of TNF-α, IL-6, IL-10 in the plasma of patients with lung cancer who received radiation therapy (RT), and to analyze the correlation between these cytokines and radiation pneumonitis (RP). Materials and Methods: Patients with lung cancer who received 3D-CRT in our hospital were prospectively evaluated. Circulating cytokine levels were measured with ELISA before RT and at the end of RT. Regular follow-up was undertaken 3 months after RT. Statistical analysis was applied to determine the relevance of cytokines to radiation-induced lung injury. Results: Of 104 patients, 29 (27.9%) developed RP. The levels of TNF-α and IL-6 levels in the plasma after RT were significantly higher than before RT (p<0.05), whereas IL -10 levels were significantly lower after RT than before RT (p<0.05). Before RT, TNF-α levels were higher in RP group (p<0.05),but there were no differences in TNF-α levels after RT. No association was observed between IL-6 and IL-10 levels and the risk of RP. Univariate analysis showed that baseline pulmonary function, smoking history, histopathology, lung volume receiving ≥20 Gy (V20), Mean lung dose (MLD) and total radiation dose were related to RP, but only MLD was an independent risk factor for RP in lung cancer patients (OR>1). Conclusion: TNF-α levels in plasma were closely related to RP but still cannot be used as predictors for RP.
H. Yu, Dr. X. Tang, D. Shu, C. Geng, C. Gong, S. Hang, D. Chen, Volume 15, Issue 1 (1-2017)
Abstract
Background: Boron neutron capture therapy (BNCT) is a radiotherapy that combines biological targeting and high linear energy transfer. A potential therapeutic approach for non-small cell lung cancer (NSCLC) is considered. However, dose in lung tumor is not homogeneous, and it will reduce the effect of BNCT treatment. In order to improve the dose distribution of BNCT, the multi-field irradiation strategy and its effects need to be explored. Materials and Methods: Common NSCLC model was defined in Chinese hybrid reference phantom and the boron concentration in skin and tumor varied from 6 to 18 ppm and from 30 to 65 ppm, respectively. Monte Carlo method for dose distribution calculation was used. Accelerator-based neutron source called “Neuboron source” was used and multi-field source irradiation plans were designed to optimize the dose distribution. Results: Under one-field irradiation, it was not feasible to perform BNCT, because the skin dose is unlikely to meet its dose limit. Under two- and three-field irradiation, the uniformity of tumor dose was improved and the maximum dose to organs at risk (OARs) decreased. If boron concentration in skin was between 6-18 ppm, BNCT was feasible with the boron concentration in tumor reaching about 57-60 ppm for two-field irradiation and 41-45 ppm for three-field irradiation, respectively. Conclusion: The multi-field irradiation plan could improve the dose distribution and the feasibility of BNCT for NSCLC. Theoretical distributions of Boron-10 were obtained to meet the treatable requirement of BNCT, which could provide a reference for NSCLC using BNCT in future multiple-field irradiation.
M. Kong, J.w. Lee, M. Yun, Md., Ph.d., S.h. Lee, Volume 17, Issue 4 (10-2019)
Abstract
Background: No study has reported radiosensitizing effect of triptolide in lung cancer cell lines. We explored the effect and underlying molecular mechanisms of combined triptolide and irradiation treatment in lung cancer cell lines. Materials and Methods: Colony formation assays were conducted to test the radiosensitizing effect of triptolide in A549 and H460 lung cancer cell lines. Survival fractions and sensitizing enhancement ratios were calculated. To determine the underlying mechanism of triptolide and irradiation combination, immunofluorescence cytometric analysis of apoptosis was conducted after treatment with triptolide and/or 4 Gy irradiation. To explore the molecular mechanisms of apoptosis induced by triptolide and irradiation combined treatment, western blot analysis was conducted after treatment with triptolide and/or irradiation (1, 2, 3, or 4 Gy). The antibodies used for Western blotting were PARP, JNK, p53, HSP70, and Akt. Results: Combined triptolide and irradiation treatment significantly decreased the surviving fractions than irradiation alone in both cell lines. Triptolide and irradiation combination treatment also resulted in significant increase in apoptosis rates than irradiation alone in both cell lines. The expression of PARP cleavage, JNK, and p53 were prominent in the groups treated with triptolide and irradiation combination. The expression of HSP70 and Akt were suppressed in groups treated with the triptolide and irradiation combination. Conclusion: This study showed that triptolide in combination with irradiation enhanced antitumor effects in lung cancer cell lines.
Phd., I. Babalioglu, S.c. Gokce, A. Hicsonmez, S. Akyurek, Y. Aslan, T. Atakul, Volume 18, Issue 1 (1-2020)
Abstract
Aims and background: In three dimensional conformal radiotherapy (3D-CRT), treatment planning is based on computerized tomography (CT) images. However, the data obtained from CT may not be sufficient in target delination. The purpose of this study is to show the differences between the radiotherapy (RT) plans which were done with positron emission tomography (PET) fusion or not. Methods: Patients with lung cancer between February 2009 and January 2012 at our institution were assessed retrospectively. Sixty patients who were treated with 3DCRT, CT simulation images were registrated with PET images. For each patient target volumes were determined and normal tissues were revised. Wilcoxon Signed Rank Test was used to compare the two groups. Results: For gross tumor volume (GTV), clinical target volume (CTV) and planning target volume (PTV); median volume values, median mean dose values and median maximum dose values were significantly different according to use of PET. About normal tissue doses; mean lung dose (MLD), lung V20, mean and maximum esophagus dose, V50 and V60, mean heart dose and maximum medulla spinalis dose were analyzed. Conclusion: Within these parameters there were statistically significant difference except in maximum dose of esophagus and V60. In our study, we observed decreased target volumes and higher dose distrubutions for target volumes in PET registrated RT plans. According to these data, it is possible to say that optimal RT plans can be formed for lung cancer by using PET registration.
Y. Fan, G. Qiu, Q. Pan, F. Zhang, S. Luan, Volume 18, Issue 1 (1-2020)
Abstract
Background:The influence of the limit ring on the final dose distribution in the design of the lung cancer intensity-modulated radiation therapy (IMRT) plan was studied. Materials and Methods: A total of 20 patients with lung cancer in 2017 were selected. Seven radiation beams were designed for each patient, and the limit ring width (RW) was set at 0.6, 0.8, 1.0, and 1.2 cm, respectively. The distance between the inner diameter of the limit ring and the target area (RD) was set 0.6, 0.8, 1.0, and 1.2 cm, respectively. The other parameters used in the plan were set at the same position. In addition, the conformity index (CI) and homogeneity index (HI) were calculated, and normal tissues were assessed. Results: Under the condition of the same number of radiation beams and the same distance between the limit ring and the target area, the smaller the limit ring, the better the CI of the target area and the less the HI of the target area. When the size of the limit ring was set the same, the closer the limit ring was to the target area, the better the CI of the dose in the target area, and the less the HI of the target area. Conclusions: In central lung cancer, when the target volume is approximately 800 cc, the optimal dose distribution is obtained when the RW is set at 0.8 cm and the RD is set at 0.6 cm.
H. Wang, H. Chen, Y. Shao, J.m. Wang, J.d. Guo, X.w. Cai, X.i. Fu, Prof. Z.y. Xu, Volume 18, Issue 3 (7-2020)
Abstract
Background: The pattern of interfractional tumor changes during limited disease small-cell lung cancer (LD-SCLC) radiotherapy is not clear, The study was to evaluate tumor changes based on interfractional CBCT images and it’s impact on dosimetry. Material and Method: We analyzed tumor changes and it’s dosimetry impact for 30 LD-SCLC patients who were treated with concurrent chemoradiotherapy(cCRT). CBCT images were acquired for each patient every five fractions before each treatment. The grass tumor volume(GTV) and total lung were adapted to create the GTVn and total lungn based on CBCTn. Dose was recalculated for every CBCT fraction. The impact on target dose coverage and lung sparing was also evaluated while relevant tissue's CT density correction was done on plan CT combined with tumor changes adapted by fraction’s CBCT images. Results: Mean GTV volume of each CBCT fraction reduced,and mean GTV volume of 7th CBCT fraction shrank nearly 10% compared to 1st fraction. The centroid positions of left/right tumors moved towards the right/left direction gradually. Most left/right tumor borders had a trend of rightward/leftward shrinkage. Target dose coverage and lung tissue dose volume increased through fractions. CT image density correction slightly increased the target dose coverage and lung tissue dose volume. Conclusion: Tumor shrinkage was seen for LD-SCLC patients, it’s related to the tumor's initial volume and location. It is appropriate that most LD-SCLC patients should be intervened at 21st radiotherapy fraction.
Ph.d., M. Zabihzadeh, Z. Ghahremani, S.m. Hoseini, H. Shahbazian, M. Hoseini Ghahfarokhi, Volume 18, Issue 3 (7-2020)
Abstract
Background: Presence of inhomogeneities such as lung tissue with low density can perturbs the dose distribution in the path of therapeutic photon beam and causes undesired cold or hot spots. The aim of this study was to investigate the effect of lung tissue inhomogeneities on dose distribution in thorax irradiation. Materials and Methods: The Monte Carlo simulation (MC) code of EGSnrc-based BEAMnrc was used to calculate dose distribution for 6 MV- Siemens Primus linear accelerator (Linac) in a homogenous phantom. Dose perturbation and inhomogeneity corrected factors (ICFs) were calculated due to implementation of lung tissue depended to the lung density and field size. Results: The maximum increased dose in lung tissue with lung density of 0.5 and 0.25gr/cm3 was 15.9%, 16.2%, 15.6%, 23.8 %, 24.8% and 25.0% for 6 × 6, 10 × 10 and 20 × 20 cm2 field sizes, respectively. The maximum ICF for these field sizes was 1.16 and 1.25 for lung density of 0.5 and 0.25gr/cm3, respectively. The maximum dose reduction in lung tissue with density of 0.25 and 0.5gr/cm3 was 19.5% and 4.2 %, and the related ICF was estimated 0.84 and 0.95, respectively. Conclusion: Involvement of lung tissue in the path of irradiation perturbs the dose distribution which is dependent to the lung density and field size. The ICFs resulted from our MC model could be useful to accurately calculate the dose distribution in radiotherapy of lung abnormalities.
|
|