فهرست مطالب

  • Volume:18 Issue: 3, 2020
  • تاریخ انتشار: 1399/04/09
  • تعداد عناوین: 27
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  • H.J. Kim*, J.S. Lee, W.C. Kim Pages 383-388
    Background

    Stereotactic body radiotherapy (SBRT) is an emerging treatment option which allows for extreme hypofractionation using modern technologies, because the low α/β-ratio favors the use of high dose per fraction in prostate cancer. There is a need for more data about SBRT. We provide a long-term update of SBRT clinical outcome using CyberKnife for the treatment of localized prostate cancer.

    Materials and Methods

    This study was based on a retrospective analysis of 43 patients treated with SBRT using CyberKnife for localized prostate cancer (23.3% in low risk, 67.4% in intermediate risk and 9.3% in high risk). The target volume included the prostate with or without the seminal vesicles depending on the risk stratification and uncertainty margins that are kept at 3-5 mm. Total dose of 36.25 Gy in 5 fractions of 7.25 Gy were administered.

    Results

    43 patients with a median 73.6 months (range, 14 to 119 months) follow-up were analyzed. There was three biochemical failure (BCF). Eight-year BCF free survival and overall survival were 92.0% and 73.1%, respectively. Median PSA decline rates were -0.301, -0.191 and -0.115 ng/mL/month, respectively, for durations of 1, 2 and 3 years after radiotherapy and has remained plateau. Median PSA nadir was 0.27 ng/mL at median 38 months and PSA bounce (median 0.33 ng/mL) occurred in 32.6% (n = 14) of patients at median 19 months after SBRT. There was no grade 3 acute and late toxicity.

    Conclusion

    Our long-term experience with SBRT using CyberKnife for localized prostate cancer demonstrates favorable efficacy and toxicity.

    Keywords: CyberKnife, prostate cancer, stereotactic body radiotherapy, prostate-specific antigen, radiotherapy, hypofractionation
  • S.J. Lee, Y.K. Kwak, E.Y. Park, S.W. Lee, S.Y. Sung, B.O. Choi* Pages 389-396
    Background

    After the mastectomy, the complication is different depending on the sequence and method of breast reconstruction and Radiotherapy (RT). The aim of the current study was to investigate complication rates, related factors, and time to complications in breast cancer patients who underwent mastectomy with immediate autologous breast reconstruction (IABR) and adjuvant RT.

    Materials and Methods

    Between April 2009 and January 2017, 52 patients underwent mastectomy with IABR followed by RT. Medical records of patients were retrospectively reviewed. Complications occurring after RT initiation were evaluated in four aspects: fat necrosis, wound infection, revision surgery, and re-reconstruction and classified into: 1) minor complication requiring only conservative treatment, and 2) major complication requiring surgical correction. All patients received RT on the chest wall including total flap. Ipsilateral axillary, supraclavicular and internal mammary regions were included at physician’s discretion. Median RT dose was 50.4 Gy (range, 50.4 – 59.4 Gy).

    Results

    Median follow up duration was 22.3 months (range, 5.3-98.6 months). Complication after RT initiation occurred in 9 (17.3%) patients. Six (11.5%) patients showed minor complications. Three (5.8%) patients developed major complications. Median time to occurrence of complication after RT was 8.6 months (range, 1.8–25.1 months). Two-thirds of complications occurred within one year, while 88.9% occurred within two years after RT. No factor showed correlation with complication.

    Conclusions

    IABR followed by adjuvant RT may be a reasonable option for patients who underwent mastectomy, in terms of postoperative complication. Complications occur most frequently within 1 year after initiation of RT, and most occur within 2 years.

    Keywords: Radiotherapy, breast reconstruction, mastectomy, complication
  • Sk.A.K. Arafin*, A. El-Taher, A.K.M. Fazlul Hoque, M. Ashraful Hoque, J. Ferdous, M. Joynal Abedi Pages 397-404
    Background

    The present work was conducted on some soil samples collected from Shamnagar upazila of Satkhira district of south-west part of world largest mangrove forest Sundarban Rezion, Bangladesh which were affected by natural disaster cyclone Aila.

    Materials and Methods

    The soil samples were analyzed to determine terrestrial γ-ray activity using HPGe γ-ray spectrometry. The measurements conducted in the current study showed that primordial radionuclides namely the 238U and 232Th and 40K are contained in all the soil samples.

    Results and Discussion

    The obtained results of the average activity concentrations of 238U, 232Th and 40K were found to be within the range of the world average of 17-60, 11-64, 140-850 Bq.kg-1 reported by UNSCEAR. The radiation dose is below the permissible limit of 1mSvy-1 recommended by IAEA (2007). No peak of 137Cs from the decay activity was found in the spectrum in the present work.

    Conclusion

    The present work will be useful in providing environmental monitoring data base of those particular areas.

    Keywords: Disaster, Aila, health, natural radiation
  • O. Ozmen*, O. Kavrik Pages 405-412
    Background

    The aim of this study was to investigate hepatic lesions induced by the 2.45 GHz electromagnetic radiation (EMR) of Wi-Fi and the protective effects of Vitamin C (Vit C) in rats.

    Materials and Methods

    Eighteen Sprague-Dawley female rats were randomly distributed into three groups, each containing six rats. The groups were Control, EMR (EMR, 1 h/day for 30 days) and EMR + Vit C (EMR, 1 h/day for 30 days and Vit C, 250 mg/kg/daily). At the end of the study, blood and liver tissue samples were collected for laboratory examinations.

    Results

    Serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels were increased in the EMR group compared with the control group. Liver histology of rats in the EMR group revealed severe hyperemia, slight degeneration, and lipidosis. Caspase-3, hypoxia-inducible factor-1 (HIF-1), and HIF-2 immunoexpression was increased, and Sirtuin-1 (SIRT-1) expression was markedly decreased in hepatocytes in the EMR group. Vit C treatment ameliorated both biochemical and pathological findings.

    Conclusion

    The results of this study showed that 2.45 GHz (Wi-Fi) EMR can cause liver damage in rats, but Vit C has an ameliorative effect.

    Keywords: Wi-Fi, vitamin C, liver, pathology, caspase-3, HIF-1a, HIF-2a, SIRT-1, immunohistochemistry
  • S.S.A. Jahanbani, A.H. Rezaeyan, H. Ghaffari, A.R. Babae, G.H. Haddadi, M.M. Moeni, A. Jomehzadeh, S. Moatamedi, S.H. Eftekhar Vaghefi* Pages 413-420
    Background

    Radiation-induced lung injury is a common complication after esophageal, breast, etc. cancer radiotherapy. We aimed to evaluate the radioprotective effect of arbutin on acute radiation-induced lung damage in male rats.

    Materials and Methods

    Fifty-two male Wistar rats were divided into 4 groups: (i) control group (n = 10), (ii) vehicle group (n = 10, received distilled water intraperitoneally (ip)), (iii) X-irradiation only (n=16, chest was irradiated to a single dose of 20 Gy x-rays) and (iv) arbutin + X-irradiation (n=16, 75 mg/kg of arbutin 2 hours before irradiation (ip), and then their chest was exposed to 20 Gy x-rays). For histopathological investigation, 8 animals of each group were sacrificed 8 weeks after treatment and the rest of them were sacrificed 3 months after treatment.

    Results

    The histopathological analysis in 8 weeks after X-irradiation showed that there was a significant increase in inflammatory in X-irradiation only group compared to control group. The administration of arbutin 2 hours prior to X-irradiation significantly reduced inflammation and inflammatory factors such as macrophages, mast cell and neutrophil in arbutin + X-irradiation group compared to X-irradiation only group (P<0.05). The histopathologic investigation performed 3 months after lung irradiation indicated a significant reduction in fibrosis formation in arbutin + X-irradiation group compared to irradiation only group (P<0.05). Localized chest X-irradiation with 20 Gy caused histopathologic damage to the lungs for short -term.

    Conclusion

    Arbutin has a great potential in reducing the histopathologic damage to lung tissue after thoracic irradiation.

    Keywords: Arbutin, lung irradiation, radioprotector, pneumonia, fibrosis
  • J.S. Welsh, J.J. Bevelacqua, H. Mozdarani, S.A.R. Mortazavi, S.M.J. Mortazavi* Pages 421-426

    Astronauts are exposed to a wide variety of stressors ranging from radiation and microgravity to persistent fluids shifts, circadian shifts and the psychological stress of prolonged isolation and confinement. On deep space missions, beyond the range of the Earth's magnetosphere, ionizing radiation may increase oxidative stress and DNA damage, immune system dysregulation and alter the effectiveness of the cellular defense mechanisms. By reviewing the health problems reported by astronauts participated in previous space missions, it is evident that viral infections are not rare in space. Recent reports suggest that COVID-19 can last for a long time in communities. Although NASA implements countermeasures designed to limit crew illness during space missions such as a pre-flight quarantine, it is not clear whether an outbreak can be prevented. Currently, it is not likely that astronauts could get a viral infection, but the consequences of potential life-threatening viral diseases such as COVID-19 should be better characterized. In this paper we discuss why COVID-19 fatality in space might be significantly higher than on the Earth. The reasons for such an increased risk include 1) uselessness of social distancing due to microgravity 2) immune system dysregulation 3) possibly higher mutation rates of RNA viruses such as the novel coronavirus (SARS-CoV-2) 4) existence of strong selective pressure and 5) decreased maximum oxygen uptake. Given these considerations, the combined effects of microgravity, space radiation (and possibly other major space stressors) on the immune system of astronauts exposed to SARS-CoV-2 and possible interactions of the virus, space stressors and host should be carefully investigated.

    Keywords: Coronavirus, COVID-19, Immune system, Space, Astronauts, Microgravity, Space radiation, SARS-CoV-2
  • B.A. El Badry, T.I. Al Naggar*, G.A. Khouqeer Pages 427-435
    Background

    The existence of radioactive isotopes and toxic elements in water poses a potential threat to public health. Due to the high consumption of bottled water, the focus of this study is on measuring the concentration of radioactive isotopes (222Rn and 226Ra) and toxic elements (Cr, Mn, Co, Ni, Cu, Zn, Cd, Pb) in different brands of bottled drinking water.

    Materials and Methods

    Therefore, twenty-four samples of bottled water have been carefully selected from local markets in Saudi Arabia. Nuclear track detector of type CR-39 and Inductive Coupled Plasma-Mass Spectrometer were used to measure radioactivity concentrations and toxic elements, respectively.

    Results

    It is observed that the activity concentration of 222Rn and 226Ra in all samples was lower than the recommended values set by different agencies such as WHO, and EPA. The annual effective dose for three age groups (infants, children, and adults) was calculated from the concentration of 222Rn. These measurements provide basic information for consumers who could be at risk of exposure through bottled water consumption.

    Conclusion

    then all types of bottled drinking water are suitable and safe for daily population ingestion.

    Keywords: Bottled drinking water, radon, toxic elements, CR-39, inductive coupled plasma-mass spectrometer
  • M. Manavalan*, M. Duraisamy, V. Subramani, H.F. Godson, G. Krishnan, M. Venkataraman, T. Ganesh Pages 437-447
    Background

    Accurate dosimetry in CyberKnife® is challenging because of the unavailability of suitable detectors to satisfy all the criteria of small-field dosimetry. In this work, eight different small-field detectors from PTW and IBA Dosimetry were used to determine the dosimetric parameters for twelve fixed collimators in the CyberKnife® radiosurgery system. The scope of this work was to assist medical physicists in detector selection in small-field dosimetry.

    Materials and Methods

    Dosimetric parameters such as the surface dose (Ds), dose buildup (DB), percentage dose at 100 mm (D100), percentage dose at 200 mm (D200), depth of dose maximum (Dmax), and total scatter factor (Scp) were compared and analyzed from the acquired Percentage Depth Dose(PDD).

    Results

    Large variations in Ds were observed with different detectors for smaller collimator sizes. On analyzing the dose buildup, considerable differences were observed with all detectors from the surface to  6 mm depth for the smallest cone of 5 mm diameter. The D100 and D200 values obtained using ion chambers were higher than those using diodes, likely due to the volume averaging effect. The depth of dose maximum was found to increase with increase in the field size for most of the detectors. Considerable variation in Scp was noticed with all detectors in smaller field ranges.

    Conclusion

    For small fields, the selection of detector is crucial, and awareness of the advantages, disadvantages and limitations of the detectors used is crucial. As in absolute dosimetry, the relative dosimetry in small fields is challenging and requires further studies and recommendations.

    Keywords: CyberKnife®, detectors, PinPoint chamber, diodes, PDD, small field dosimetry
  • B. Mohsenzadeh, M.R. Deevband*, R. Paydar, M. Ghorbani Pages 449-460
    Background

    The present study aimed to investigate patient dose in common X-ray examinations to estimate effective dose in the digital radiography in Iran.

    Materials and Methods

    Entrance surface dose (ESD) was measured based on applied exposure parameters for the common actual examination; and then effective dose (ED) was calculated by use of PCXMC software. The study was conducted on 15358 patients in 85 X-ray rooms; and the necessary data was collected for five age groups, 0-1 year, 1-5 years, 5-10 years, 10-15 years old and adults in each projection.

    Results

    The ranges of ESD and ED in different examinations for all the age groups are 0.02-10.20 mGy and 2.42-378.96 µSv respectively.

    Conclusion

    The effective dose as criteria can be used to reduce patients' doses. The special considerations such as: adequate training of imaging staff; updating clinical audits; patient dose considerations; implementation of systematic and regular quality assurance and quality control programs in medical imaging departments should be taken into account to optimize radiological practices.

    Keywords: Patient dose, dose reference level, dosimetry in diagnostic radiology, entrance surface dose, effective dose
  • H. Wang, H. Chen, Y. Shao, J.M. Wang, J.D. Guo, X.W. Cai, X.I. Fu, Z.Y. Xu* Pages 457-475
    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.

    Keywords: Tumor shrinkage, interfractional cone beam CT, dosimetry, limited disease (LD) small-cell lung cancer
  • A.S. Hameed*, A.K. Hashim, E. Jasim Mohammed Pages 461-466
    Background

    Many people in Iraq and indeed the world choose to drink coffee on a daily basis; accordingly, we planned to find the radium and uranium concentrations in addition to the Radon emission rate to determine if coffee shows the levels of radioactivity that may affect people’s lives.

    Material and Methods

    A nuclear track detector (CR-39) was used to study the natural radioactivity of ten samples of coffee collected from local Iraqi markets.

    Results

    The effective radium content varied from 0.13 to 0.66 Bq/kg with a mean 0.32 Bq/kg. The mass exhalation rates of radon vary from 0.024 – 0.121/kg .h, with a mean 0.059 Bq/kg .h, while the surface exhalation rates of radon vary from 0.47 – 2.39/2.h, with a mean 1.16 Bq/m2. h. Uranium content varied from 0.10 to 0.54 ppm with a mean value of 0.26 ppm.

    Conclusion

    Insofar as health effects are concerned, the results have shown that all the samples were entirely safe.

    Keywords: Coffee, CR-39, radon exhalation rates, radium
  • A. Inal*, E. Duman, E.E. Ozkan Pages 477-486
    Background

    We aimed to investigate the accordance of Critical Organ Scoring Index (COSI), Conformity Index (CI) and Normal Tissue Complication Probability (NTCP) parameters with Dose Volume Histograms (DVH) used for evaluation of 3 different pelvic radiotherapy plans.

    Materials and Methods

    Ten gynecologic carcinoma patients who underwent adjuvant radiotherapy were enrolled in this study. Treatment plans were created with conformal treatment planning (3DCRT) and intensity modulated radiation therapy (IMRT) to a total dose of 50.4 Gy in 28 fractions. Initially, volume related dose evaluation was done via DVH. Subsequently, HI, CI, COSI and NTCP for selected normal tissues were calculated for each plan and compared with DVH parameters. Finally, a graphical demonstration was evaluated to see if the results were in accordance with DVH.

    Results

    CI results were statistically significant in favor of IMRT (p<0.001). Rectum V40Gy decreased with 9IMRT compared to 3DCRT and 7IMRT (p=0.013 and p=0.013). V40Gy for bladder was also lower with 9IMRT compared with 3DCRT and 7IMRT (p=0.005 and p=0.012). COSI calculations revealed better small intestine protection in IMRT plans similar with DVH (p=0.005 and p=0.022). Femoral heads were better protected with IMRT plans were better compared to 3DCRT in NTCP calculations (p=0.002). Normal tissue protection was worst with 3DCRT via both DVH and COSI evaluations (p=0.001 and p<0.001 respectively).

    Conclusion

    Using the indexes in this study to decide the most appropriate plan among multiple treatment plans in gynecologic cancer patients will be timesaving and easier in comparison with evaluating the DVH of every alternative plan.

    Keywords: Gynecological radiotherapy, treatment planning, dosimetric evaluation
  • S.M. Hosseini, M. Momennezhad*, SH. Naseri Pages 487-494
    Background

    Breast conserving surgery followed by adjuvant whole breast radiotherapy is the accepted treatment in early-stage breast cancer. Due to breast irregularities, it is difficult to achieve homogenous dose distribution with conventional techniques. Currently, it is possible to use varied breast irradiation techniques such as field-in-field (FIF) that is claimed to produce more homogenous distribution of doses within the target volumes while sparing the organs at risk, leading to a better treatment outcome. The present study aimed to compare the conventional and the FIF techniques dosimetrically.

    Materials and Methods

    Twenty patients with early-stage breast cancer underwent computed tomography. Two different treatment plans were created for each patient: the wedge-based (conventional) plan and the FIF plan. Dosimetric parameters and monitor units were compared with paired sample t-test.

    Results

    FIF technique obtained significantly lower dose homogeneity index, lower maximum doses and higher median doses in PTV (P<0.05). Similarly, the conformity index, and mean doses were higher in the FIF technique but the differences were not significant (P>0.05). In ipsilateral lungs, FIF significantly reduced the maximum and mean doses (P<0.05), and showed a tendency to reduce V20 (P>0.05). In patients with left-sided breast cancer, minimum and maximum doses and V40 of heart were significantly decreased in FIF plans (P<0.05). Doses to the contralateral lungs did not differ significantly.

    Conclusion

    These results along with significantly less monitor units required for therapy in FIF suggest that this technique may be more advantageous during breast irradiation.

    Keywords: field-in-field, 3D conformal radiotherapy, wedge, breast irradiation, OAR dose
  • F. Pakniyat, S. Gholami, H.A. Nedaie*, H. Mozdarani, A. Mahmoudzadeh, M. Salimi Pages 495-504
    Background

    The Linear Quadratic (LQ) equation as the most common formula in radiotherapy has a debatable accuracy in modeling high-dose effects. The purpose of this study was to demonstrate bystander response of the Grid treatment in SCC cell line, based on both theoretical calculations and experimental investigations.

    Materials and methods

    The linear quadratic model was used to calculate the equivalent uniform dose (EUD) of a Grid-field with the 10 Gy maximum doses. According to the EUD definition, the identical tumor survival fraction (SF) was expected to obtain from both Grid and open-field single fraction. After observing the difference, the clonogenic and apoptosis assays were exerted to investigate bystander response via medium transfer strategy which was performed from 10Gy-irradiated donors to 1.5Gy-irradiated recipients.

    Results

    The EUD was equal to 4 Gy and the SF of 4 Gy EUD and 10 Gy Grid-field were 0.1 ± 0.02 and 0.051 ± 0.008, respectively. These findings contradicted the theoretical expectations of their survivals equality. Moreover, the bystander clonogenic cells death enhanced approximately by 2.91 times (statistically significant); highlighting the bystander response role. The apoptotic findings illustrated that the bystander cells experienced an approximately 10% increase and the apoptotic rate confirmed the clonogenic survival result which was less in the EUD than the Grid-field.

    Conclusion

    Since the SF of the Grid-field was less than the EUD, it revealed the Grid therapeutic advantages plus bystander response manifestation; that was ignored in the LQ equation and may not be demonstrated by sheer theoretical calculations of the modulated-field.

    Keywords: Linear quadratic, grid, bystander, clonogenic survival, apoptosis
  • Kh. Masood, A. Ullah, A. Hussain, Kh. Mahmood, G.R. Hart, W. Muhammad* Pages 505-510
    Background

    Dosimetry audits have an important role to safely deliver the prescribed radiation dose to the cancerous area.  It not only maintains and improve the treatment standards but also identify issues that are potentially harmful to the patients. This article presents the results of a comparative study of beam output measurements of a high-energy photon beam emitted from a medical linear accelerator.

    Materials and Methods

    The measurements were performed by an International Atomic Energy Commission (IAEA) Quality Assurance/Quality Control survey mission (level-I dosimetry), a national Secondary Standard Dosimetry Laboratory (SSDL) experts (level-II dosimetry) and hospital physicists (level-III dosimetry). Glass dosimeters and cylindrical ionization chambers for level I and cylindrical ionization chambers for level-II and -III dosimetry were used in water by following IAEA TRS-398 protocol.

    Results

    The level-I dosimetry results of glass dosimeters and ionization chambers were compared and percent deviations of -0.4 % and 0.3 % were found for 6 and 15 MV-photon beams, respectively. Similarly, level-II and -III dosimetry results with respect to level-I are in good agreement and within the optimum uncertainty level of ±5%. The annual level-II dosimetry quality audits (i.e., from 2010 to 2015) showed that only one dosimetry audit is out of the optimum level set for this study. However, it is within the tolerance level set for level-II quality audit programs (i.e., < ±5%).

    Conclusion

    In conclusion, this article has demonstrated consistent radiotherapy radiation dosimetry results for MV-photons beams. It also showed quantitative information in-line with the currently achieved accuracy and precision of external megavoltage photon beam dosimetry. Furthermore, this study also established a baseline for current routine audits of radiotherapy dosimetry. Studies of this type are essential to appropriately follow the recommendations and procedures of the pertinent dosimetry protocols.

    Keywords: Radiotherapy, level-I, -II, -III radiation dosimetry, on-site dosimetry tours, quality audits
  • F. Omidvar, F. Bouzarjomehri*, F. Falahati, M.H. Zare Pages 511-519
    Background

    Cardiac catheterization plays an essential role in the evaluation of suspected heart failure patients. This work aimed to determine the mean effective dose of patients undergoing catheterization tests and to estimate the associated radiation risk of malignancy.

    Material and Methods

    Measurements were performed during 65 coronary angiographies (CA), 70 coronary angioplasties (PTCA) 27, radio fluoroscopy (RF) ablations and 25 electro physiologies procedures in a dedicated laboratory. The procedures were undertaken with the Siemens and General Electric X-ray equipment. A dose area product (DAP) meter was also used. The DAP values and fluoroscopy times were recorded for each patient.

    Results

    The mean DAP values and patient effective doses were 19.53 Gy.cm2 and 1.71 mSv for CA, 49.74 Gy.cm2 and 4.57 mSv for PTCA, 153.34 Gy.cm2 and 16.38 mSv for ablations and 14.88 Gy.cm2 and 1.65 mSv for electrophysiology, respectively. The patient radiation risk was estimated at 13, 1.3, 1.3, 3.6 fatal cancer per 10000 procedures of ablations, electrophysiology, CA and PTCA cases, respectively.

    Conclusion

    Results showed that the radiation risk due to RF cardiac ablation is higher than the other complication procedures so, efforts should be made to minimize patient radiation risk from RF ablation procedures. Also we found no clear correlation between cardiologist level of experience and reduced level of patient’s dose.

    Keywords: patient dosimetry, DAP, cardiac catheterization, effective dose, radiation risk
  • M. Chun, J.I. Kim, D.H. Oh, H.G. Wu, J.M. Park* Pages 521-530
    Background

    This study aims to investigate the effect of reference dose calculation grid size (RDCGS) on gamma passing rate (GPR) for patient-specific quality assurance of intensity-modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT).

    Materials and Methods

    A total of 20 patients were retrospectively selected. Both IMRT and VMAT plans were generated for each patient. Reference dose distributions for gamma analysis were calculated with RDCGS of 1–5 mm at intervals of 1 mm. Dose distributions were measured using MapCHECK2 and ArcCHECK dosimeters. Both global and local gamma analyses with gamma criteria of 3%/3 mm, 2%/3 mm, 2%/2 mm, and 2%/1 mm were performed with various RDCGS.

    Results

    As the RDCGS increased from 1 mm to 5 mm, the average global GPRs with 2%/2 mm for VMAT with MapCHECK2 and ArcCHECK decreased by 9.3% and 5.9%, respectively. The average local GPRs decreased by 14% and 11.7%, respectively. For IMRT, the global GPRs decreased by 4.8% and 6%, respectively, whereas the local GPRs decreased by 10.5% and 8.6%, respectively. The effect of the RDCGS on the GPRs became larger when performing local gamma analysis as well as when applying small distance-to-agreement (DTA). As the RDCGS increased, the average changes in the GPR per mm of DTA change increased regardless of the type of radiotherapy, detector, or gamma analysis.

    Conclusion

    For an accurate verification of the IMRT and VMAT plans, it is recommended that the reference dose distribution must be calculated with the smallest possible RDCGS.

    Keywords: Dose calculation grid, gamma analysis, intensity-modulated radiation therapy, patient-specific QA, volumetric modulated arc therapy
  • H. Kaizu*, M. Hata, K. Mitsudo, Y. Hayashi, E. Ito, M. Sugiura, S. Takano, Y. Mukai, I. Koike, T. Koizumi Pages 531-538
    Background

    The optimal radiation dose for oral cavity cancers treated with retrograde superselective intra-arterial chemoradiotherapy (SIACRT) is unclear. The aim of the present study was to evaluate the treatment outcome and toxicity in patients treated with <60 Gy compared with those treated with ≥60 Gy to provide evidence for determining the optimal dose.

    Materials and Methods

    Between January 2009 and December 2013, 159 oral cavity cancer patients were treated with SIACRT with curative intent at a single institution. One hundred and twenty-nine patients received ≥60 Gy and 30 received <60 Gy. Local control (LC), disease-free survival (DFS), overall survival (OS), and toxicity were compared. Propensity score matching was performed to reduce bias.

    Results

    The median follow-up period was 48 months (range, 2–88 months). LC (<60 Gy vs. ≥60 Gy, 81.5% vs. 86.1% at 3 years, p = 0.534), DFS (68.8% vs. 72.4% at 3 years, p = 0.816), and OS (85.9% vs. 72.3% at 3 years, p = 0.132) were comparable between the two groups. There was also no difference in toxicity. However, the median overall treatment period was significantly shorter in the <60 Gy cohort (39 days vs. 49 days, p < 0.0001).

    Conclusion

    The radiation dose may be reduced to <60 Gy when treating oral cavity cancers with SIACRT.

    Keywords: Catheterization, chemoradiotherapy, oral cancer, survival rate, toxicity
  • S.H. Mousavie Anijdan, A. Gholami, A. Lahooti* Pages 539-547
    Background

    The main aim of this study is to radiolabel dextran coated iron oxide nanoparticles (NPs) (with 80 nm hydrodynamic size) with the Indium-111 and evaluation their biodistribution after intravenous injection normal mice.

    Materials and Method

    The chelator Diethylenetriamine Pentaacetic Acid (DTPA) dianhydride was conjugated to SPION using a small modification of the well-known cyclic anhydride method at a ratio of 1:5 (NPs:DTPA) molar ratio. The reaction was purified with magnetic assorting columns (MACs) using high gradient magnetic field following incubation. Then the radiochemical purity of the radiolabeled NPs were determined using RTLC method. The magnetic properties of nanoparticles were measured by a 1.5 tesla clinical human MRI.

    Results

    The NPs showed high super paramagnetic properties whereas their r2/r1 was 17.6. The RTLC showed that the purity of compound was above 99% after purification and the compound has shown a good in-vitro stability until 6 hours in the presence of human serum. The biodistribution of 111In-DTPA-NPs in mice demonstrated high uptake in the reticuloendothelial system (RES) and the blood clearance was so fast.

    Conclusion

    Due to magnificent uptakes of this radiotracer in the liver and spleen, its stability and their fast clearance from other tissues, especially in blood, it is suggested that this radiotracer would be suitable for RES theranostics purposes.

    Keywords: Dextran-coated superparamagnetic iron oxide, 111In radioisotope, biodistribution, theranostics, reticuloendothelial system, radiopharmaceuticals
  • J. Chen*, Y. Xiao, L. Wu, F. Xiao, Q. Wang, J. Hong, P. Zhu Pages 549-555
    Background

    To investigate effect of radiosensitization of [Ru(bpy)2(phen)]Cl2 complex on nasopharyngeal carcinoma cell line CNE1 and its mechanism.

    Materials and Methods

    Nasopharyngeal carcinoma cell line CNE1 in vitro culture was divided into control group, light irradiation group (4 Gy, 6 MV photonic line), simple metal ruthenium complex treatment group (Ru group, 100 μmol/L [Ru(bpy)2(phen)]Cl2) and metal ruthenium complex combined with radiotherapy group (Combined radiotherapy group, cells were irradiated with 4 Gy and 6 MV photons at 2 days after 100 μmol/L [Ru(bpy)2(phen)]Cl2).

    Results

    Transcriptional level of P53 gene in combined radiotherapy group was higher than that in the other groups (P<0.001). Inhibition rate of combined radiotherapy group was higher than that of Ru group and irradiation group (P<0.001). Apoptotic rate was the highest (P<0.05) in the combined radiotherapy group, and irradiation group was higher than Ru group and control group (P<0.05). Survival rate of Ru group was lower than that of control group under the same radiation dose (P<0.05), and the radiotherapy sensitization ratio was 1.227 (Dq ratio).

    Conclusion

    [Ru(bpy)2(phen)]Cl2 increases the sensitivity of nasopharyngeal carcinoma cell line CNE1 to X-ray, which may be related to increase of P53 gene expression.

    Keywords: [Ru(bpy)2(phen)]Cl2, nasopharyngeal carcinoma cells, P53 gene, radiosensitization
  • K. Venkatesan, C.J. Raphael, K.M. Varghese, P. Gopu, S. Sivakumar, M. Boban, N.A.N. Raj, K. Senthilnathan, P. Ramesh Babu* Pages 557-569
    Background

    To study and analyze the variations in delivered doses to rectum and bladder of carcinoma prostate patients by using kilo Voltage (kV) ‘Cone Beam Computed Tomography’ (CBCT) images.

    Materials and Methods

    2-Dimensional kilo Voltage (2D kV) Imaging and CBCT were done for seven prostate cancer patients. The deviations among their shifts were correlated and the volumetric changes of the rectum and bladder were analyzed. Rectum and bladder contours were redrawn on every boost fractions and dose calculation were performed on CBCT images to study the effect on dose volume histograms.

    Results

    A correlation coefficient for set-up variations was within 0.78 for all directions between CBCT soft tissue matching and kV bone match. The mean deviation of bladder and rectum volume over the boost fractions was -12% to +9% (SD 31cc to 70cc) and -10.2% to+12% (SD 3.1cc to14.9cc), respectively. Bladder mean dose variation was <1.5Gy for all three positions whereas it was <3.65Gy for rectum. D1% dose deviation from reference plan for bladder was 1.1Gy (CBCT matched position), 1.4Gy (kV matched position), and 1.7Gy (no correction), and for rectum, the deviations were 1.2Gy, 2.2Gy, 3.6Gy, respectively. No significant deviation was found statistically significant at the low dose region.

    Conclusion

    It is possible to achieve good dose delivery and conformity in target (prostate) with CBCT image guidance rather than kV bone match, but dose contribution to the rectum is dependent on the patient’s anatomy, bladder filling, and rectum filling, pertaining to the day of examination.

    Keywords: Image-guided radiotherapy, prostate, bladder, rectum
  • M.K. Ozbilgin*, G.Z. Karaman, S. Gencur, E. Gumustepe, C. Kurtman Pages 571-578
    Background

    Adrenomedullin (AM) and its receptor, receptor activity-modifying protein (RAMP) 2 have pleiotropic regulatory functions in normal tissue and cancer tissue. AM is produced and secreted both numerous stromal cells and tumor cells. This study aims to investigate a possible role of AM and RAMP2 in the radiation exposure in the normal lung tissue.

    Materials and Methods

    Four groups with 6 male adult Swiss Albino mice per group were investigated. The mice were subjected to a 500 cGy single-dose radiation exposure in the total body radiation device and lung tissues were collected. 1, 2, and 7 days after radiation exposure, with 1 reference group which was not exposed to radiation.

    Results

    The general histology and the immunohistochemistry of the tissue samples prepared with anti- AM, anti–RAMP2, and monoclonal antibodies were investigated, yielding a statistically significant increase for AM on day 3 and for RAMP2 on day 1 after radiation exposure.

    Conclusion

    The observed increase of AM and RAMP2 concentrations in the normal tissue matrix after radiation exposure may play a role in the side effects of radiotherapy.

    Keywords: AM, RAMP2, radiation, lung, carcinogens
  • M. Zabihzadeh*, Z. Ghahremani, S.M. Hoseini, H. Shahbazian, M. Hoseini Ghahfarokhi Pages 579-586
    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.

    Keywords: Electronic disequilibrium, lung cancer radiotherapy, Monte Carlo simulation, inhomogeneity correction factor
  • A. Salehi, K. Ebrahimpour, F. Forouharmajd*, M. Zarean Pages 587-592
    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.

    Keywords: Electronic disequilibrium, lung cancer radiotherapy, Monte Carlo simulation, inhomogeneity correction factor
  • S. Kim*, E. Han Pages 593-598
    Background

    we aimed to find the optimal level of ethanol that can be added such that the radiochemical purity of [18F]FDG is increased and the MFDS and USP stipulated guidelines are met.

    Materials and Methods

    Changes in the radiochemical purity of [18F]FDG were analyzed according to changes in the concentrations of ethanol added. The study used 1 L of 99.9% pure ethanol. The ethanol concentrations used were 0.0% (0 µL) for the control group and 0.1% (1 µL), 0.2% (2 µL), and 0.3% (3 µL) for the experimental groups. Since the radiochemical purity of [18F]FDG may differ according to the radioactive concentrations used, four different radioactive concentrations were prepared: 1580 mCi/16 mL, 3320 mCi/16 mL, 4840 mCi/16 mL, and 6470 mCi/16 mL.

    Results

    The radiochemical purity of [18F]FDG increased significantly when ethanol was added to it at different radioactive concentrations in comparison to when ethanol was not added. When ethanol concentrations of 0.1%, 0.2%, and 0.3% were added, the radiochemical purity increased at all radioactive concentrations (100 mCi/mL, 200 mCi/mL, 300 mCi/mL, and 400 mCi/mL) while meeting the KP and USP standards even after 10 hours following the EOS.

    Conclusion

    It was determined in our study that adding ethanol at the concentration of 0.1% to [18F]FDG is most suitable as it generates the least residual ethanol while maintaining the radiochemical purity of [18F]FDG at stable levels that meet the KP and USP standards.

    Keywords: [18F]FDG, ethanol, radiochemical purity, radiopharmaceutical, US pharmacopeia, Korean pharmacopeia
  • Y. Mori*, T. Mori, K. Adachi, S. Abe, Y. Oshima, A. Takeuchi, M. Ito Pages 599-604

    The treatment results of intensity-modulated stereotactic radiotherapy (IM-SRT) by volumetric-modulated arc therapy (VMAT) for intramedullary cervical spinal cord metastases (IMCSCM) in two cases were presented. Case 1: A 76-year-old woman showed left-sided motor weakness and left arm pain and dysesthesia due to IMCSCM at C [cervical] 6-7 (located a little to the left laterally) with multiple small brain metastases from thyroid carcinoma.  Multiple brain metastases were successfully treated by stereotactic radiosurgery (SRS). In addition, IMCSCM was treated by IM-SRT. Case 2: A 48-year-old man presented with asymptomatic IMCSCM at C2 (located a little to the right laterally) after conventional whole brain radiotherapy (WBRT) and multiple sessions of SRS/SRT for multiple brain metastases from lung adenocarcinoma. IMCSCM was treated by IM-SRT. In both cases 39 Gy in 13 fractions (without PTV [planning target volume] margin, D95%=95% dose) was delivered to the IMCSCM (0.3 ml and 0.5 ml in volume respectively) by coplanar 2-full circular arc VMAT. The maximum dose to the tumor was 46.3 Gy in case 1 and 47.1 Gy in case 2. IMCSCM in both cases shrank markedly without adverse effects during the follow-up period of 32 months and 8 months respectively. The symptoms of the extremities in case 1 were subsided completely until the patient’s death at 34 months after SRT from lung metastasis. In case 1 IMCSCM had been thought to be a relatively radioresistant thyroid carcinoma metastasis. In case 2 IMCSCM was near the field of the prior WBRT. However, both tumors were successfully treated without adverse effects by VMAT IM-SRT.

    Keywords: Metastasis, spinal cord, intramedullary, cervical, volumetric-modulated arc therapy
  • X. Liang, W. Shi, X. Wang, J. Qin, L. Wang, X. Wu, H. Zhang*, Y. Tan Pages 605-610
    Background

    Intracerebral schwannoma is an extremely rare disease, accounting for fewer than 1% of intracranial schwannomas. The most common site for this type of schwannoma is the cerebral hemisphere, especially the frontal and temporal lobes; brainstem schwannoma is infrequent.

    Case Description

    Here, we report a 51-year-old man with a monthlong history of blurred vision and weakness in his left lower limb. Magnetic resonance imaging showed a heterogeneous cystic tumor with a solid nodule arising from the brainstem. The patient underwent a craniotomy with complete resection of the tumor, which was confirmed to be a brainstem schwannoma by histopathological examination. We also performed a literature review of the 19 reported cases of brainstem schwannoma.

    Conclusions

    Brainstem schwannomas predominated in children and young adults (60% of cases occurred in patients ≤ 30 years of age), and were more common in females (65%). Most of these schwannomas exhibited heterogeneous intensity, containing cystic (78%) and solid-enhanced components. The vast majority of reported cases (94.9%) followed a benign course, with an improved prognosis following tumor resection.

    Keywords: Brainstem schwannoma, clinical, imaging features