جستجوی مقالات مرتبط با کلیدواژه "پرتودرمانی تطبیقی" در نشریات گروه "پزشکی"

Head 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).

The 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.

Upon 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.

Our 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.

Nasopharyngeal 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.

This 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.

Compared 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.

HT 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.

Breast 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.

CT 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.

The 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.

The 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.

The 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.

This 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.

Results 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.

It 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.

The aim of this study was to predict and compare the dose received by normal critical organs in radiotherapy of stage one seminoma in conventional (2-dimensional or 2D) and conformal (3-dimensional or 3D) methods.
Conventional treatment was designed based on bony anatomy, and conformal treatment based on vessels and nodal anatomy, for 10 patients with 6-MV photon and total dose of 25 Gy. Dose distribution of inside and outside of field was measured (with the profiler system) and calculated (with a treatment planning system).
Findings: Mean received dose was 5.58 and 7.16, 20.67 and 19.29, 5.20 and 3.19, 9.73 and 6.43, 5.96 and 7.60 Gy for kidneys, pancreas, liver, stomach, and colon in conventional and conformal methods, respectively. For organs out of the field, mean received dose was 1.55 and 1.48 Gy for right and left kidneys in conventional and conformal methods, respectively. Moreover, the mean received dose by testis was 7 and 6 cGy in conventional and conformal methods, respectively.
In conformal treatment method, due to more accurate design of target volume, probability of recurrence was less, and the damage to kidneys and colon was predicted more.

Hodgkin 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.
The 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%).
For 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.