scholarly journals An Attempted Substitute Study of Total Skin Electron Therapy Technique by Using Helical Photon Tomotherapy with Helical Irradiation of the Total Skin Treatment: A Phantom Result

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Chi-Ta Lin ◽  
An-Cheng Shiau ◽  
Hui-Ju Tien ◽  
Hsin-Pei Yeh ◽  
Pei-Wei Shueng ◽  
...  
Keyword(s):  
Organs At Risk ◽  
Treatment Technique ◽  
Dose Distributions ◽  
Target Region ◽  
Electron Therapy ◽  
Therapy Technique ◽  
Treatment Dose ◽  
Dose Homogeneity ◽  
Dose Measurements ◽  
Uniform Treatment

An anthropomorphic phantom was used to investigate a treatment technique and analyze the dose distributions for helical irradiation of the total skin (HITS) by helical tomotherapy (HT). Hypothetical bolus of thicknesses of 0, 10, and 15 mm was added around the phantom body to account for the dose homogeneity and setup uncertainty. A central core structure was assigned as a “complete block” to force the dose tangential delivery. HITS technique with prescribed dose (Dp) of 36 Gy in 36 fractions was generated. The radiochromic EBT2 films were used for the dose measurements. The target region with 95.0% of theDpreceived by more than 95% of the PTV was obtained. The calculated mean doses for the organs at risk (OARs) were 4.69, 3.10, 3.20, and 2.94 Gy for the lung, heart, liver, and kidneys, respectively. The measurement doses on a phantom surface for a plan with 10 mm hypothetical bolus and bolus thicknesses of 0, 1, 2, and 3 mm are 89.5%, 111.4%, 116.9%, and 117.7% ofDp, respectively. HITS can provide an accurate and uniform treatment dose in the skin with limited doses to OARs and is safe to replace a total skin electron beam regimen.

scholarly journals Comparison of dose distributions in target areas and organs at risk in conformal and VMAT techniques and dose verifications with the use of thermoluminescence dosimetry

Nukleonika ◽  
2020 ◽  
Vol 65 (4) ◽  
pp. 217-222
Author(s):  
Monika Paluch-Ferszt ◽  
Beata Kozłowska ◽  
Marcin Dybek
Keyword(s):  
At Risk ◽  
Organs At Risk ◽  
Volumetric Modulated Arc Therapy ◽  
Planning System ◽  
Treatment Planning System ◽  
Dose Distributions ◽  
Monte Carlo Algorithms ◽  
Thermoluminescence Dosimetry ◽  
Collapsed Cone ◽  
Dose Measurements

AbstractThe aim of the present study is to compare dose distributions and their verification in target areas and organs at risk (OAR) in conformal and volumetric modulated arc therapy (VMAT) techniques. Proper verification procedures allow the removal of the major sources of errors, such as incorrect application of a planning system, its insufficient or cursory commissioning, as well as an erroneous interpretation of the obtained results. Three target areas (head and neck, chest, and pelvic) were selected and the treatment was delivered based on plans made using collapsed cone convolution and Monte Carlo algorithms with 6-MV photon beams, adopting conformal and VMAT techniques, respectively. All the plans were prepared for the anthropomorphic phantom. Dose measurements were performed with TL detectors made of LiF phosphor doped with magnesium and titanium (LiF:Mg,Ti). This paper presents the results of TL measurements and calculated doses, as well as their deviations from the treatment planning system (TPS) in the three planned target areas. It was established that the algorithms subject to analysis differ, particularly in dose calculations for highly inhomogeneous regions (OAR). Aside from the need to achieve the dose intended for the tumour, the choice of irradiation technique in teleradiotherapy should be dictated by the degree of exposure to individual critical organs during irradiation. While nothing deviated beyond the bounds of what is acceptable by international regulatory bodies in plans from TPS, clinically one must be more cautious with the OAR areas.

Study on the Application of Magnetic Nanoparticles as Drug Delivery Particles on the Atopic Dermatitis

2013 ◽  
Vol 750 ◽  
pp. 180-183
Author(s):  
Gang An ◽  
Ping Ma ◽  
Dong Ying Ju ◽  
Takashi Kumazawa
Keyword(s):  
Drug Delivery ◽  
Atopic Dermatitis ◽  
Magnetic Nanoparticles ◽  
Medical Treatment ◽  
Magnetite Nanoparticles ◽  
Treatment Technique ◽  
Mice Model ◽  
Target Region ◽  
Better Than

It is well known that the advances in the biomedicinal applications of magnetite nanoparticles were studied recently. As a drug delivery tools, it only affects on the target region of illness. We investigated the application of magnetic nanoparticles as drug delivery tools by the mice model of atopic dermatitis. The results involve that after magnetic nanoparticles are applied to the skin, the condition of atopic dermatitis becomes much better than the former one of atopic mice model. It only affects on the illness region and healthy regions almost have no influence. It is suitable for the medical treatment technique usage on the atopic dermatitis.

scholarly journals A Case Series of Dosimetric Comparison-VMAT (RapidArc), IMRT, 3DCRT for Extended Field Radiotherapy in Cervical Cancer

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Praveen Kumar Marimuthu ◽  
◽  
Sasipriya Ponniah ◽  
Govindaraj Ganesan ◽  
Prabhu Ramamoorthy ◽  
...  
Keyword(s):  
Cervical Cancer ◽  
At Risk ◽  
Lymph Nodes ◽  
Organs At Risk ◽  
Whole Body ◽  
Conformity Index ◽  
Treatment Technique ◽  
Integral Dose ◽  
Intensity Modulated ◽  
Extended Field

Purpose: To compare plans of 3DCRT, IMRT and VMAT (RapidArc) and evaluate them in different dosimetric aspects along with dose to organs at risk with each technique to determine the best treatment technique for Extended field RT in cervical cancer patients Material & Methods: We evaluated External Beam radiotherapy plans of 10 patients of FIGO 2018 stage rIIIC2 who received Extended Field Radiotherapy (EFRT) to primary site along with regional nodes-bilateral external, internal iliac lymph nodes, presacral and para-aortic lymph nodes. The dose prescribed for all patients was 50.4Gy/28 fractions at 180cGy/fraction. Few patients had received gross nodal boost following this, but for better comparison only the initial phase of 50.4Gy/28 fractions was considered. All patients were planned with 3DCRT, IMRT and RapidArc. We evaluated and compared these plans dosimetrically in terms of Homogeneity Index, Conformity Index, Target Volume Coverage, Gradient Index, Unified Dosimetry Index, Integral dose, Monitor units and Doses to Organs at risk such as Anorectum, Bladder, Bowel Bag, Bilateral Femoral Heads, Bilateral Kidneys and Bone Marrow. Results: Intensity modulated techniques RapidArc and IMRT significantly spared critical organs compared to 3DCRT. Between RapidArc and IMRT, the critical organ sparing was comparable, but RapidArc had better target coverage, lesser MU and lesser treatment time. All techniques had acceptable HI, CI, GI, UDI and whole body Integral dose. Conclusion: Intensity modulated techniques should be the standard for EFRT in cervical cancer. Both RapidArc and IMRT are acceptable techniques of treatment delivery although the former may be preferred if and when available.

scholarly journals A convolutional neural network approach for IMRT dose distribution prediction in prostate cancer patients

2019 ◽  
Vol 60 (5) ◽  
pp. 685-693 ◽  
Author(s):  
Tomohiro Kajikawa ◽  
Noriyuki Kadoya ◽  
Kengo Ito ◽  
Yoshiki Takayama ◽  
Takahito Chiba ◽  
...  
Keyword(s):  
Neural Network ◽  
Prostate Cancer ◽  
Convolutional Neural Network ◽  
Cancer Patients ◽  
Dose Distribution ◽  
Organs At Risk ◽  
Model Performance ◽  
Estimation Algorithm ◽  
Neural Network Approach ◽  
Dose Distributions

Abstract The purpose of the study was to compare a 3D convolutional neural network (CNN) with the conventional machine learning method for predicting intensity-modulated radiation therapy (IMRT) dose distribution using only contours in prostate cancer. In this study, which included 95 IMRT-treated prostate cancer patients with available dose distributions and contours for planning target volume (PTVs) and organs at risk (OARs), a supervised-learning approach was used for training, where the dose for a voxel set in the dataset was defined as the label. The adaptive moment estimation algorithm was employed for optimizing a 3D U-net similar network. Eighty cases were used for the training and validation set in 5-fold cross-validation, and the remaining 15 cases were used as the test set. The predicted dose distributions were compared with the clinical dose distributions, and the model performance was evaluated by comparison with RapidPlan™. Dose–volume histogram (DVH) parameters were calculated for each contour as evaluation indexes. The mean absolute errors (MAE) with one standard deviation (1SD) between the clinical and CNN-predicted doses were 1.10% ± 0.64%, 2.50% ± 1.17%, 2.04% ± 1.40%, and 2.08% ± 1.99% for D2, D98 in PTV-1 and V65 in rectum and V65 in bladder, respectively, whereas the MAEs with 1SD between the clinical and the RapidPlan™-generated doses were 1.01% ± 0.66%, 2.15% ± 1.25%, 5.34% ± 2.13% and 3.04% ± 1.79%, respectively. Our CNN model could predict dose distributions that were superior or comparable with that generated by RapidPlan™, suggesting the potential of CNN in dose distribution prediction.

Long-Term Results of a Highly Performing Conformal Electron Therapy Technique for Chest Wall Irradiation After Mastectomy

2017 ◽  
Vol 98 (1) ◽  
pp. 206-214 ◽  
Author(s):  
Noemie Grellier Adedjouma ◽  
Marion Chevrier ◽  
Alain Fourquet ◽  
Emilie Costa ◽  
Haoping Xu ◽  
...  
Keyword(s):  
Chest Wall ◽  
Long Term Results ◽  
Electron Therapy ◽  
Therapy Technique

Mid-Line Tissue Dose and Lethality in X-Irradiated Rats

1958 ◽  
Vol 194 (2) ◽  
pp. 316-318
Author(s):  
J. G. Kereiakes
Keyword(s):  
Relative Effectiveness ◽  
Animal Tissue ◽  
X Rays ◽  
Experimental Conditions ◽  
Dose Distributions ◽  
Tissue Dose ◽  
Depth Dose ◽  
Dose Measurements ◽  
Made In

The ld50 values were determined for rats exposed to 100–250 kvp x-rays for doses expressed ‘in air’ and ‘in tissue.’ Dose measurements were made in animal tissue. For the ld50 ‘in tissue’ doses, the relative effectiveness was approximately one for all qualities. For the experimental conditions of the study, it seems that mid-line tissue dose may be the proper parameter for acute lethality in rats exposed to x-radiations having different depth dose distributions.

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