جستجوی مقالات مرتبط با کلیدواژه « Conformal Radiotherapy » در نشریات گروه « پزشکی »
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IntroductionIn the present scenario, high precision-radiotherapy is delivered through Linear accelerators in which the dose delivery is achieved by delivering the proper monitor unit (MU). Treatment planning for the patients is carried out through treatment planning systems (TPS) in which the precise computation of MU is crucial. This TPS - calculated MU has to be verified using manual calculations for accurate dose delivery. In this study, we incorporated our in-house developed multi leaf collimator(MLC) shaper software and the well-known Clarkson method to compare the calculated MUs to the TPS-generated MUs.Material and MethodsConformal treatment plans of various sites of 30 patients were randomly selected containing different MLC-shaped field sizes. All the fields were shaped using MLC (leaf width of 1cm, 40 pairs) in the TPS. MLC log files were exported and fed into the in-house shaper software to get crucial inputs for the Clarkson-based calculation. The Tissue Maximum Ratio(TMR) & Scatter Maximum ratio(SMR) were utilized in our investigation. The Clarkson MU calculation was compared with the TPS calculation method. Paired t-test was performed for the statistical significance.ResultsThe Clarkson method-based calculated had significant differences for all the esophageal cancers (p<0.05); however no significant difference was found in the other sites.ConclusionThe compared MUs were within the acceptable deviation with the TPS for Head & Neck, Prostrate and Cervical cancer. The estimated MUs had significant difference in non-homogenous medium. The shaper software can be further enhanced to receive MLC log files from the TPS.Keywords: Radiation Therapy, Conformal Radiotherapy, Dosimetry Calculations, Computer Assisted}
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IntroductionEarly-stage glottic cancer has a high cure rate with definitive radiotherapy. Historical reports show excellent local control. The present study evaluated the outcomes of early glottic cancer patients treated with a hypofractionated radiotherapy schedule of 60Gy in 20 fractions.Material and MethodsThis is a retrospective study of patients with stage I glottic cancer who received radical intent LINAC-based hypo-fractionated 3D conformal radiotherapy with a dose 60Gy in 20 fractions. The primary objective was to assess the locoregional control (LRC), and secondary objectives were to determine disease-free survival (DFS), overall survival (OS), and toxicity.ResultsThe analysis included 105 patients from the age range of 35-88 years. About 69% of patients were over 60 years of age. The median overall treatment time (OTT) was 26 days (24 – 30 days). The mean follow-up was 74 months, ranging from 9 to 135 months. Seven patients had locoregional recurrence after an initial complete clinical response. Six had local, and one had a regional nodal recurrence. DFS at five years and ten years were 83% and 69%, and OS at five years and ten years were 87% and 80%, respectively. Most patients reported grade I skin reactions and tolerated the treatment well. We did not observe any late adverse events such as persistent laryngeal edema or radiation necrosis.ConclusionThe radiotherapy schedule of 60Gy in 20 fractions over four weeks offers comparable local disease control with reasonable long-term side effects in T1 glottic cancer.Keywords: Laryngeal cancer, Early Glottic cancer, T1 Cancer of Larynx, Radiotherapy, Hypofractionation Radiation Dose, Conformal Radiotherapy}
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مقدمه
این مطالعه با هدف مقایسه ی احتمال کنترل تومور (Tumor control probability) TCP و احتمال عوارض بافت طبیعی (Normal tissue complication probability) NTCP پرتودرمانی سه بعدی تطبیقی (Three-dimensional conformal radiotherapy) 3D-CRT و توموتراپی برای سرطان پستان پاندولی سمت چپ با استفاده از مدل های رادیوبیولوژیکی انجام شد.
روش هامطالعه ی حاضر بر روی 20 بیمار مبتلا به سرطان پستان پاندولی سمت چپ انجام شد که با استفاده از سیستم طراحی درمان برای روش های 3D-CRT و توموتراپی طراحی شده بودند. دز تجویزی 50 گری برای حجم هدف برنامه ریزی (Planning target volume) PTV به ترتیب برای طرح های 3D-CRT و توموتراپی اجرا شد. دز معادل یکنواخت (Equivalent uniform dose) EUD مدل نایمیریکو برای تخمین احتمال کنترل تومور و احتمال عوارض بافت طبیعی استفاده شد.
یافته هابا توجه به نتایج، میانگین مقادیر TCP برای طرح های درمان روش 3D-CRT و توموتراپی به ترتیب 0/13 ± 99/07 و 0/09 ± 99/32 بود که از نظر آماری تفاوت معنی داری نشان نداد. NTCPهای مربوط به ریه و قلب در طرح های درمان روش توموتراپی در مقایسه با 3D-CRT به طور قابل توجهی کمتر بود.
نتیجه گیریاز نقطه نظر رادیوبیولوژیکی، نتایج نشان داد که روش 3D-CRT، NTCP کمتری را برای ریه ی همان طرف تولید می کند. در مقابل، TCP در روش توموتراپی در مقایسه با روش 3D-CRT افزایش نشان داد.
کلید واژگان: سرطان پستان, رادیوتراپی تطبیقی سه بعدی, توموتراپی, پریکاردیت, پنومونی}BackgroundThis study aimed to compare the tumor control probability (TCP) and the normal tissue complications probability (NTCP) of three-dimensional adaptive radiation therapy (3D-CRT) and tomotherapy for left pendular breast cancer using radiobiological models.
MethodsThe current study was conducted on 20 patients with left pendular breast cancer who underwent treatment planning using the treatment planning system for 3D-CRT and tomotherapy. A prescribed dose of 50 Gy was implemented for the planning target volume (PTV) in both 3D-CRT and tomotherapy designs. The Equivalent Uniform Dose (EUD) of the Niemierko model was used to estimate the tumor control probability (TCP) and the normal tissue complications probability (NTCP).
FindingsAccording to the results, the average TCP values for 3D-CRT and tomotherapy plans were 99.07 ± 0.13 and 99.32 ± 0.09, respectively, which did not show a statistically significant difference. The NTCP values for the lung and heart were significantly lower in tomotherapy plans compared to 3D-CRT plans.
ConclusionFrom a radiobiological point of view, the results showed that 3D-CRT resulted in a lower NTCP for the ipsilateral lung. In contrast, for TCP calculations, tomotherapy plans showed higher values compared to 3D-CRT plans.
Keywords: Breast Neoplasms, Conformal radiotherapy, Intensity-modulated radiotherapy, Pericarditis, Pneumonia} -
مقدمه :
سرطان سر و گردن (Head and neck cancer) جزء ده سرطان شایع در سراسر جهان است. به دلیل پیچیدگی آناتومی سر و گردن، در هنگام پرتودرمانی اندام های زیادی دوز دریافت می کنند. هدف این مطالعه، مقایسه ی دوز رسیده به حلزون گوش در دو روش (Three-Dimensional Conformal Radiotherapy) 3D-CRT و (Helical Tomotherapy) HT بود.
روش هامطالعه ی حاضر کاربردی و مقطعی است. 28 بیمار که دارای سرطان نازوفارنکس بوده و به بیمارستان سیدالشهدا (امید) برای درمان بین سال های 1399-1401 مراجعه کرده و کاندید درمان با یکی از دستگاه های 3D-CRT و یا HT می باشند؛ در این مطالعه قرار گرفتند. طرح درمانی برای هر بیمار در دو دستگاه، شبیه سازی شده و سپس متغیرهای مطالعه مانند حداکثر و میانگین دوز و شاخص های همگنی و انطباق مورد بررسی قرار گرفتند.
یافته هابا مقایسه ی طرح های درمانی HT و 3D-CRT، میانگین دوز قابل دریافت حلزون گوش و سایر اندام های در معرض خطر در روش HT نسبت به روش 3D-CRT کاهش یافته و تفاوت قابل توجهی داشته اند، که نشان می دهد اختلاف معنی داری بین دو روش وجود دارد.
نتیجه گیریطبق داده های مطالعه ی ما روی بیماران مبتلا به سرطان نازوفارنکس، نتایج نشان داد که HT از همگنی و انطباق هدف بهتری برخوردار است و دوز تحویلی به (Organ At Risk) OARها را در مقایسه با 3D-CRT معمولی کاهش می دهد.
کلید واژگان: سرطان سر و گردن, نازوفارنکس, پرتودرمانی تطبیقی, توموتراپی, حلزون گوش}BackgroundHead and neck cancer (HNC) is among the ten most common cancers worldwide. Due to the complex head and neck anatomy, many organs receive radiation during treatment. The aim of this study is to compare the cochlea dose in two different treatment methods, 3D-CRT (Three-Dimensional Conformal Radiotherapy) and HT (Helical Tomotherapy).
MethodsThe current study is applied and cross-sectional. 28 patients who had nasopharyngeal cancer and were referred to Seyed al-Shohada Hospital (Omid) for treatment between 2020-2022 and are candidates for treatment with one of the 3D-CRT or HT devices; were included in this study. The treatment plan for each patient was simulated in two devices and then study variables such as maximum and average dose and homogeneity and conformity index were investigated.
FindingsUpon comparing the treatment plans of Helical Tomotherapy (HT) and Three-Dimensional Conformal Radiation Therapy (3D-CRT), it was found that the average dose received by organs at risk, such as the cochlea, was significantly lower in the HT method compared to the 3D-CRT method. This indicates a significant difference between the two treatment methods.
ConclusionOur study on patients with nasopharyngeal cancer revealed that Helical Tomotherapy (HT) treatment led to better target homogeneity and compliance compared to conventional Three-Dimensional Conformal Radiation Therapy (3D-CRT). Additionally, HT was found to reduce the dose delivered to organs at risk (OARs) in comparison to 3D-CRT.
Keywords: Head, neck cancer, nasopharynx, Conformal radiotherapy, Tomotherapy, cochlea} -
مقدمه :
سرطان نازوفارنکس، یکی از سرطان های رایج سر و گردن است که درمان اصلی برای این نوع سرطان، رادیوتراپی می باشد. هدف این مطالعه، بررسی و مقایسه ی دوز ارگان های در معرض خطر در دو روش سه بعدی تطبیقی و توموتراپی مارپیچی در بیماران مبتلا به سرطان سر و گردن می باشد.
روش هامطالعه ی حاضر از نوع گذشته نگر و تجربی مقطعی می باشد. برای انجام این مطالعه، تصاویر سی تی اسکن 16 بیمار مبتلا به مراحل اولیه ی سرطان نازوفارنکس با میانگین سنی 81-16 سال (3/16 ± 7/42) که به صورت تصادفی انتخاب شدند، دریافت شد. ارگان های در معرض خطر و حجم هدف آن ها توسط پزشک کانتور شد و طرح درمان بیماران برای دو روش (Helical Tomotherapy) HT و 3D-CRT (Three-Dimensional Conformal Radiation Therapy) طراحی گردید. در پایان با استفاده از هیستوگرام حجم- دوز (Volume-Dose histogram) DVH متغیرهای دزیمتری ارگان های در معرض خطر و حجم هدف استخراخ و با یکدیگر مقایسه شد.
یافته هاروش HT نسبت به 3D-CRT شاخص همگنی و شاخص تطابق را بهبود بخشید. همچنین دوز OAR مورد مطالعه را نسبت به 3D-CRT به طور معنی داری کاهش داد، گرچه دوز برخی از این ارگان ها از محدودیت دوز تعیین شده خارج شدند.
نتیجه گیریروش HT به دلیل پوشش دهی بهتر حجم هدف و همچنین عملکرد بهتر در حفظ OARها نسبت به روش 3D-CRT برای درمان بیماران مبتلا به سرطان نازوفارنکس که کاندید دریافت رادیوتراپی هستند، ارجحیت دارد.
کلید واژگان: سرطان نازوفارنکس, پرتودرمانی, دزیمتری, پرتودرمانی تطبیقی, توموتراپی}BackgroundNasopharyngeal cancer is one of the common head and neck cancers and the main treatment for this type of cancer is radiotherapy. The purpose of this study is to investigate and compare the dose of organs at risk in two adaptive three-dimensional methods (3D-CRT) and helical tomotherapy (HT) in patients with head and neck cancers.
MethodsThis study is a cross-sectional experimental retrospective study and to conduct this study, CT scan images (Computed Tomography) of 16 patients with early stages of NPC with an average age range of 16-81 years (42.7 ± 16.3) those were randomly selected. The organs at risk and their target volume were contoured and the treatment plan of the patients was done for both HT and 3D-CRT methods. In the end, using a Volume-Dose histogram (DVH), the dosimetry variables of organs at risk and target volume were extracted and compared with each other.
FindingsCompared to 3D-CRT, the HT method improved the homogeneity index and concordance index. It also significantly reduced the dose of the studied OARs compared to 3D-CRT, although the dose of some of these organs exceeded the prescribed dose limit.
ConclusionHT method is a better technique for treating nasopharyngeal cancer patients who are candidates for radiotherapy due to better coverage of the target volume and also, better performance in preserving OARs compared to the 3D-CRT method.
Keywords: Nasopharyngeal cancer, Radiotherapy, Dosimetry, Conformal radiotherapy, Tomotherapy} -
مقایسه ی دزیمتریک درمان سرطان پستان چپ با استفاده از دو روش پرتودرمانی تطبیقی سه بعدی و توموتراپی
مقدمه :
سرطان پستان، شایع ترین نوع سرطان بدخیم زنان در کل جهان و دومین سرطان کشنده در میان زنان پس از سرطان ریه است. این مطالعه، با هدف مقایسه ی تفاوت های دزیمتریک بر اساس دو طرح درمان پرتودرمانی برای سرطان پستان چپ بعد از عمل جراحی بود.
روش هااطلاعات سی تی اسکن 20 بیمار کاندید پرتودرمانی مبتلا به سرطان پستان چپ که به طور تصادفی ساده انتخاب شدند به نرم افزار طراحی درمان ارسال گردید. اندام هدف (پستان چپ) و اعضای در معرض خطر شامل ریه ها، قلب، پستان راست توسط رادیوآنکولوژیست کانتور گردید. طراحی درمان پرتودرمانی تطبیقی سه بعدی (Three-dimensional conformal radiotherapy) 3D-CRT با استفاده از دو پرتو مماس مخالف هم، بستگی به آناتومی بیمار با و بدون وج و انرژی 6 مگاولت طراحی گردید. طراحی درمان توموتراپی با انرژی 6 مگاولت انجام شد. در آخر، با استفاده از منحنی توزیع دز-حجم (Dose-volume histogram) DVH متغیرهای دزیمتری اندام هدف و اندام های در معرض خطر استخراج و با یکدیگر مقایسه گردید.
یافته هاروش پرتودرمانی تطبیقی سه بعدی نسبت به روش توموتراپی، میانگین دز اندام هدف و اندام های در معرض خطر را کاهش داد. شاخص انطباق و شاخص همگنی در روش توموتراپی بهبود یافت، اگرچه پوشش حجم اندام ریه ی چپ در دزهای پایین نسبت به روش پرتودرمانی تطبیقی سه بعدی افزایش پیدا کرد.
نتیجه گیریروش توموتراپی نسبت به روش پرتودرمانی تطبیقی سه بعدی، به دلیل بهبود پوشش حجم هدف و توزیع دز بهتر، روش مناسب تری برای درمان می باشد.
کلید واژگان: سرطان پستان, پرتودرمانی تطبیقی, توموتراپی, دزیمتری, قلب, ریه}Dosimetric Comparison of Treatment of Left Breast Cancer Using 3-Dimention Conformal Radiotherapy Technique and TomotherapyBackgroundBreast cancer is the most common type of malignancy seen in women globally and the second life-threatening cancer among women after lung cancer. This research aims to compare the dosimetric differences based on two radiotherapy treatment plans for left breast cancer after surgery.
MethodsCT scan data from 20 patients who were candidates for radiotherapy diagnosed with left breast cancer were randomly selected and sent to the treatment design software. The target organ (left breast) and organs at risk including lungs, heart, right breast were contoured by the radio-oncologist. The design of three-dimensional conformal radiotherapy (3D-CRT) was designed using two opposite tangential beams, depending on the patient's anatomy, with and without wedge and with energy of 6 MV. The tomotherapy treatment was designed with an energy of 6 MV. Finally, using the dose-volume distribution curve (DVH), the dosimetric variables of the target organ and the organs at risk were extracted and compared with each other.
FindingsThe three-dimensional conformal radiotherapy method reduced the average dose of the target organ and organs at risk compared to the tomotherapy method. The compliance index and homogeneity index were improved in the tomotherapy method, although the volume coverage of the left lung organ increased at low doses compared to the three-dimensional conformal radiotherapy method.
ConclusionThe tomotherapy method is a more suitable method for treatment than the three-dimensional conformal radiotherapy method as it enhances the target volume coverage and offers a better dose distribution.
Keywords: Breast Neoplasms, Conformal radiotherapy, Tomotherapy, Film dosimetry, Heart, Lung} -
Background
In this study, computed tomography/magnetic resonance imaging (CT/MRI) image registration and fusion in the 3D conformal radiotherapy treatment planning of Glioblastoma brain tumor was investigated. Good CT/MRI image registration and fusion made a great impact on dose calculation and treatment planning accuracy. Indeed, the uncertainly associated with the registration and fusion methods must be well verified and communicated. Unfortunately, there is no standard procedure or mathematical formalism to perform this verification due to noise, distortion, and complicated anatomical situations.
ObjectivesThis study aimed at assessing the effective contribution of MRI in Glioma radiotherapy treatment by improving the localization of target volumes and organs at risk (OARs). It is also a question to provide clinicians with some suitable metrics to evaluate the CT/MRI image registration and fusion results.
MethodsQuantitative image registration and fusion evaluation were used in this study to compare Eclipse TPS tools and Elastix CT/MRI image registration fusion. Thus, Dice score coefficient (DSC), Jaccard similarity coefficient (JSC), and Hausdorff distance (HD) were found to be suitable metrics for the evaluation and comparison of the image registration and fusion methods of Eclipse TPS and Elastix.
ResultsThe programmed tumor’s volumes (PTV) delineated on CT slices were approximately 1.38 times smaller than those delineated on CT/MRI fused images. Large differences were observed for the edema and the brainstem. It was also found that MRI considerably optimized the dose to be delivered to the optic nerve and brainstem.
ConclusionsImage registration and fusion is a fundamental step for suitable and efficient Glioma treatment planning in 3D conformal radiotherapy that ensure accurate dose delivery and unnecessary OAR irradiation. MRI can provide accurate localization of targeted volumes leading to better irradiation control of Glioma tumor.
Keywords: X-Ray Computed Tomography, Magnetic Resonance Imaging, Conformal Radiotherapy, Glioma, Radiotherapy} -
Background
In this study, computed tomography/magnetic resonance imaging (CT/MRI) image registration and fusion in the 3D conformal radiotherapy treatment planning of Glioblastoma brain tumor was investigated. Good CT/MRI image registration and fusion made a great impact on dose calculation and treatment planning accuracy. Indeed, the uncertainly associated with the registration and fusion methods must be well verified and communicated. Unfortunately, there is no standard procedure or mathematical formalism to perform this verification due to noise, distortion, and complicated anatomical situations.
ObjectivesThis study aimed at assessing the effective contribution of MRI in Glioma radiotherapy treatment by improving the localization of target volumes and organs at risk (OARs). It is also a question to provide clinicians with some suitable metrics to evaluate the CT/MRI image registration and fusion results.
MethodsQuantitative image registration and fusion evaluation were used in this study to compare Eclipse TPS tools and Elastix CT/MRI image registration fusion. Thus, Dice score coefficient (DSC), Jaccard similarity coefficient (JSC), and Hausdorff distance (HD) were found to be suitable metrics for the evaluation and comparison of the image registration and fusion methods of Eclipse TPS and Elastix.
ResultsThe programmed tumor’s volumes (PTV) delineated on CT slices were approximately 1.38 times smaller than those delineated on CT/MRI fused images. Large differences were observed for the edema and the brainstem. It was also found that MRI considerably optimized the dose to be delivered to the optic nerve and brainstem.
ConclusionsImage registration and fusion is a fundamental step for suitable and efficient Glioma treatment planning in 3D conformal radiotherapy that ensure accurate dose delivery and unnecessary OAR irradiation. MRI can provide accurate localization of targeted volumes leading to better irradiation control of Glioma tumor.
Keywords: X-Ray Computed Tomography, Magnetic Resonance Imaging, Conformal Radiotherapy, Glioma, Radiotherapy} -
هدف
هدف این مطالعه مقایسه دزیمتریک و رادیوبیولوژیک غدد بزاقی در بیماران سرطان زبان درمان شده با تکنیک های مختلف پرتودرمانی با شدت تعدیل شده(IMRT) و تطبیقی سه بعدی(3D-CRT) می باشد.
مواد و روش هااین مطالعه بر روی طرح درمان 25 بیمار مبتلا به سرطان زبان در مرحله T2-T3/N0 صورت گرفته است. طراحی درمان بر روی تصاویر CT بیماران برای تکنیک های 3D-CRT و IMRT (با میدان های 5، 7 و9) برای همه بیماران انجام گرفت. سپس همگنی (HI) و تطابق دز (CI) در حجم هدف، بیشینه و میانگین دوز غدد بزاقی و احتمال بروز عوارض پاروتید محاسبه و مقایسه شدند.
یافته هانتایج این مطالعه حاکی از افزایش HI وCI (به ترتیب تا 54/61% و 78/28%) در IMRT نسبت به 3D-CRT می باشد. هم چنین افزایش تعداد میدان تابش در تکنیک IMRT می تواند منجر به کاهش میانگین دز رسیده به غدد زیر زبانی (تا 52/9) و کاهش بیشینه دز دریافتی غدد تحت فکی (تا 93/6%) شود. استفاده از تکنیک IMRT با 5 و 7 میدان می تواند منجر به افزایش معنادار در احتمال خشکی دهان ناشی از پرتوگیری غدد پاروتید (تا 61/8%) نسبت به تکنیک 3D-CRT شود.
نتیجه گیرینتیجه گیری می شود که استفاده از تکنیک IMRT با 9 میدان در مقایسه با تکنیک 3D-CRT در بیماران سرطان زبان، منجر به همگنی و تطابق بیش تر در هدف و دز دریافتی کم تر غدد تحت فکی و زیر زبانی می شود.
کلید واژگان: سرطان های دهان, سرطان های زبان, پرتودرمانی تطبیقی, پرتو درمانی با شدت تعدیل شده, غدد بزاقی, غدد پاروتید}Koomesh, Volume:22 Issue: 1, 2020, PP 99 -106IntroductionThe purpose of this study was to evaluate the dosimetric and radiobiological parameters of salivary glands in treatment of patients with oral tongue cancer by 3D conventional radiotherapy (3D-CRT) and intensity modulated radiation therapy (IMRT) techniques.
Materials and MethodsThis study was performed on treatment planning of patients with oral tongue cancer in T2-3/N0 cancer staging. In this way, the treatment planning was performed on CT images for 3D-CRT and IMRT techniques (with 5, 7 and 9 fields) for all patients. Then, the homogeneity (HI) and conformity index (CI) of dose in the target volume and maximum, mean does of the salivary glands and normal tissue complication probability of parotid glands were computed and compared between different treatment.
ResultsResults of this study indicated an increase in HI and CI in IMRT compared to 3D-CRT (up to 61.54% and 28.78%). Moreover, the increase in the number of beams in the IMRT technique can lead to decrease in the mean dose of sublingual glands (up to 9.52%) and decrease in the maximum dose of the submandibular glands (up to 6.93%), while, the use of IMRT with 5 and 7 beams can lead to a significant increase in the probability of xerostomia in parotid gland (up to 8.61%) compare with 3D-CRT technique.
ConclusionIt can be concluded that IMRT technique with 9 fields led to improve the salivary glands protection, more homogeneity and conformity in the target volume and reducing the received dose of submandibular and sublingual glands compare to the 3D-CRT in patient with oral tongue cancer.
Keywords: Mouth Neoplasms, Tongue Neoplasm, Conformal Radiotherapy, Intensity-Modulated Radiotherapy, Salivary Glands, Parotid Glands} -
IntroductionThe postmastectomy radiotherapy uses bolus to improve the coverage close to the skin; however, it needs to be removed in case of severe skin toxicity. This study investigated the effect of bolus parameters (i.e., frequency and thickness) for the superposition algorithm on skin dose in postmastectomy three-dimensional conformal radiotherapy (3D-CRT).Material and MethodsThe present study was carried out ona total of 22 patients. First, all the plans were calculated without using bolus. Then, the plans were recalculated using different bolus frequencies (5, 10, 15, 20, 25) and thicknesses (0.5 and 1 cm). To evaluate the dose delivered to the skin, a 2-mm thick skin was profiled, and statistical analysis was performed by studying the dosimetric parameters (i.e., minimum, mean, and maximum) of chest wall skin.ResultsThe superficial coverage of planning target volume (PTV) was better by using bolus. In the case of skin, the bolus thickness had a significant impact on the minimum and mean doses for all bolus frequencies , while there was no significant effect on the maximum before 20-bolus frequency. The bolus frequency increase demonstrated a significant difference on all dosimetric parameters of the skin , except the maximum showed no significant difference between 0 and 5-bolus frequencies .ConclusionThe obtained results indicated that the bolus use had generally a significant effect on the chest wall skin dosimetric parameters depending on bolus frequency and thickness. Therefore, the choice of bolus frequency and bolus thickness can affect the clinical decisions in certain cases.Keywords: Bolus, Postmastectomy, Chest Wall, Skin dose, Superposition, Conformal Radiotherapy}
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مقدمهلنفوم Hodgkin، یکی از بیماری های بدخیم قابل درمان است. شیوع بدخیمی های ثانویه به ویژه سرطان سینه و بیماری های قلبی- عروقی پس از رادیوتراپی، اهمیت بهینه کردن طرح درمان برای بیمار را ضروری می نماید. در این مطالعه، مقایسه ای بین انواع طرح درمان های قابل انجام با به کارگیری فوتون های 6 و 18 مگاولت بر روی ناحیه ی درمانی گردن و مدیاستن انجام گردید.روش هادر این مطالعه، با استفاده از نرم افزار TiGRT کانتورینگ تمام اعضای حساس و حجم درمانی برای 18 بیمار زن مبتلا به لنفوم Hodgkin با درگیری گردن و مدیاستن انجام شد و سپس، طرح درمان های مختلف با میدان قدامی- خلفی (AP-PA) با انرژی 6 و 18 مگاولت با وزن های مختلف مقایسه گردید.یافته هااستفاده از فوتون 18 مگاولت با وزن یکسان از قدام و خلف نسبت به فوتون رایج 6 مگاولت، سبب کاهش 9-2 درصد دز میانگین برای اعضای پستان، قلب و ریه می شود. تغییر نقطه ی طبیعی سازی از مرکز تومور به Sternal notch، اگر چه سبب کاهش دز میانگین رسیده به اعضای مورد مطالعه می گردد، اما با کاهش 13-9 درصدی دز میانگین رسیده به حجم درمانی، معیار طراحی درمان (105 درصد ± دز تجویزی) را برآورده نکرد.نتیجه گیریبرای زنان مبتلا به لنفوم Hodgkin با درگیری مدیاستن و گردن، استفاده از فوتون 18 مگاولت با وزن یکسان از قدام و خلف با برآورده کردن معیار طراحی درمان (105 درصد ± دز تجویزی) مناسب تر می باشد. قرار دادن نقطه ی ایزوسنتر در مرکز تومور نسبت به Sternal notch نتیجه ی مطلوب تری ایجاد می کند. یکنواختی بهتر توزیع دز در حجم درمان در به کارگیری فوتون 18 مگاولت حاصل می گردد.کلید واژگان: بیماری Hodgkin, طراحی درمان, پرتودرمانی تطبیقی}BackgroundHodgkin lymphoma is one of the treatable malignant diseases. The incidence of secondary cancers, especially breast cancer, and cardiovascular diseases after radiotherapy doubles the importance of patient treatment plan. In this study, some comparisons were made between a variety of treatments by using photon energy of 6 and 18 Mv on the treated areas of neck and mediastinum.MethodsThe contouring of all sensitive organs and treatment volumes were performed for 18 female patients with Hodgkin lymphoma involving neck and mediastinum, using TiGRT software. Then, comparison between different anterior-posterior (AP-PA) treatments with different weights of 6 and 18 Mv was done.
Findings: Using 18-Mv photon with the same weight of the anterior and posterior than conventional 6-Mv photon caused 2-9% reduction in mean dose to breast, heart, and lungs. Although changing the normalization (isocenter) point from the center of tumor to sternal notch reduced the mean dose of the studied organs, 9-13% reduction in the mean dose of treatment volume did not meet the criterion (prescribed dose ± 105%).ConclusionFor women with Hodgkin lymphoma involving mediastinum and neck, using 18-Mv photon with the same weight of the anterior and posterior is more appropriate to meet the design criteria of treatment (coating suitable treatment volume of prescribed dose ± 105%). Changing isocenter point from the center of the tumor to sternal notch causes a more favorable result. The better uniformity of the dose distribution in treatment volume is achieved by using 18-Mv photon.Keywords: Hodgkin Disease, Treatment planning, Conformal radiotherapy} -
Ionization radiation caused to incidence of complications in the exposed organs. In prostate radiotherapy, rectum and bladder have been radiated unwantedly and indicated some complications during and after treatment. The purpose of present study is to consider and to compare clinical complications of rectum and bladder in custom block and MLC for 3- D conformal radiotherapy, in order to determine if both treatments differ with respect to creating radiation protection, subsequently in the incidence of complications. In this respect, 72 patients with prostate cancer classified into two arms, above 60 years without the history of previous radiotherapy, hormone therapy and surgery, were selected randomly in October 2014. In one arm, patients were treated with block 3- D conformal radiotherapy, and in second arm with MLC outbound technique for 3- D radiotherapy. Rectal and bladder clinical complications were recorded before, during (at the end of 10 treatment sessions), 3 and 6 months after treatment then compared based on tables (RTOG/ LENT).Obtained results showed that patients had a significant difference in such complications as urinary frequency after 10 treatment sessions, 3 months after treatment (pKeywords: clinical complications, conformal radiotherapy, prostate cancer}
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BackgroundTo evaluate the dosimetric difference between conventional and three-dimensional conformal Radiotherapy (3D-CRT) using 6 and 18 MV X-ray photons.Materials And MethodsComputed tomography scans of 26 pelvic patients were acquired and transferred to the 3D treatment planning system. For each patient, 8 Conventional plans (3, 4, 5 and 6 Fields) and one 3D-CRT plan were prepared using 6 and 18 MV photon energies. The minimum dose (Dmin), maximum dose (Dmax) and mean dose (Dmean) to target (PTV) and organs at risk (OAR), Integral dose, Homogeneity Index and Conformity Index were compared for each plan. Also, Experimental measurements were performed using farmer ionization chamber on a patient based pelvic phantom.ResultsOn Average, six-field (6F1) plans, offer minimum dose to critical organs and sufficient dose to prostate. Increasing the beam energy lead to a decrease in Dmean of the bladder and femoral heads, as well as Dmax of PTV. The CI and ID were decreased by 4% and 11% respectively with increasing the energy and the number of beams. Experimental measurements were also in good agreement with calculations. 3D-CRT reduced Dmean of bladder, rectum and femoral heads and also CI and ID were significantly improved by 44.6% and 30.8%, respectively.ConclusionIncreasing the photon energy and number of beams, improve the treatment parameters of bladder, femoral heads and PTV, except the rectum. 3D-CRT offered the most conformity in the delivery doses to the prostate while sparing dose to OARs, uninvolved structures with lower integral dose.Keywords: Conventional, 3D, conformal radiotherapy, conformity index, integral dose, prostate cancer}
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BackgroundWe aimed to compare field-in-field technique (FIF) with conformal tangential field radiotherapy (CRT) in terms of dosimetric benefits for early stage breast cancer radiotherapy.Materials And MethodsTwenty consecutive left-side breast cancer patients who underwent breast-conserving surgery were included to the study. For each patient, two different treatment plans were created for the entire breast. FIF plans and CRT plans were compared for doses in the planning target volume (PTV), the organ at risk (OAR) volume including ipsilateral lung, heart, left ascending coronary artery (LAD) and the contralateral breast, the homogeneity index (HI), and the monitor unit (MU) counts required for the treatment. Paired samples t-test was used for statistical analysis.ResultsThe FIF technique significantly reduced the maximum dose of the PTV as well as the mean doses of the heart, LAD, ipsilateral lung and the contralateral breast (p values were <0.001 for each). When the OAR volumes irradiated with 2, 5, 10, 20, 30 and 40 Gy were compared, the results were in favor of the FIF technique. The volume receiving <20 Gy of the prescription dose for the ipsilateral lung was significantly decreased using FIF technique (p<0.001). FIF technique allowed us more homogenous dose distribution with lower MUs.ConclusionThe FIF technique provided better dose distribution in the PTV and significantly reduced the doses in the OAR. Considering the lower MUs required for treatment the FIF technique seems to be more advantageous than CRT during whole breast irradiation.Keywords: Breast cancer, conformal radiotherapy, dose volume histograms, field, in, field technique}
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