Improvements in target coverage and reduced spinal cord irradiation using intensity-modulated radiotherapy (IMRT) in patients with carcinoma of the thyroid gland

2001 ◽  
Vol 60 (2) ◽  
pp. 173-180 ◽  
Author(s):  
Christopher M Nutting ◽  
David J Convery ◽  
Vivian P Cosgrove ◽  
Carl Rowbottom ◽  
Louiza Vini ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Thyroid Gland ◽  
Intensity Modulated Radiotherapy ◽  
Target Coverage ◽  
Intensity Modulated

scholarly journals Impact of Geometric Uncertainties on Dose Distribution During Intensity Modulated Radiotherapy of Head-and-neck Cancer: The Need for a Planning Target Volume and A Planning Organ-at-Risk Volume

2006 ◽  
Vol 13 (3) ◽  
pp. 108-115 ◽  
Author(s):  
O. Ballivy ◽  
W. Parker ◽  
T. Vuong ◽  
G. Shenouda ◽  
H. Patrocinio
Keyword(s):  
Spinal Cord ◽  
At Risk ◽  
Neck Cancer ◽  
Intensity Modulated Radiotherapy ◽  
Target Volume ◽  
Ct Scans ◽  
Target Coverage ◽  
Geometric Uncertainties ◽  
Intensity Modulated ◽  
Organ At Risk

We assessed the effect of geometric uncertainties on target coverage and on dose to the organs at risk (OARS) during intensity-modulated radiotherapy (IMRT) for head-and-neck cancer, and we estimated the required margins for the planning target volume (PTV) and the planning organ-at-risk volume (PRV). For eight headand- neck cancer patients, we generated IMRT plans with localization uncertainty margins of 0 mm, 2.5 mm, and 5.0 mm. The beam intensities were then applied on repeat computed tomography (CT) scans obtained weekly during treatment, and dose distributions were recalculated. The dose–volume histogram analysis for the repeat CT scans showed that target coverage was adequate (V100 ≥ 95%) for only 12.5% of the gross tumour volumes, 54.3% of the upper-neck clinical target volumes (CTVS), and 27.4% of the lower-neck CTVS when no margins were added for PTV. The use of 2.5-mm and 5.0-mm margins significantly improved target coverage, but the mean dose to the contralateral parotid increased from 25.9 Gy to 29.2 Gy. Maximum dose to the spinal cord was above limit in 57.7%, 34.6%, and 15.4% of cases when 0-mm, 2.5-mm, and 5.0-mm margins (respectively) were used for PRV. Significant deviations from the prescribed dose can occur during IMRT treatment delivery for headand- neck cancer. The use of 2.5-mm to 5.0-mm margins for PTV and PRV greatly reduces the risk of underdosing targets and of overdosing the spinal cord.

A comparative dosimetric study comparing dose to the carotid artery using 3D conformal radiotherapy and intensity-modulated radiotherapy for T1-T2 glottic cancer at Gharbia Cancer Society, Egypt

2017 ◽  
Vol 16 (2) ◽  
pp. 177-182
Author(s):  
Mohamed Mahmoud ◽  
Safa Elfaramawy ◽  
Maha H. Mokhtar
Keyword(s):  
Spinal Cord ◽  
Carotid Artery ◽  
Intensity Modulated Radiotherapy ◽  
Conformal Radiotherapy ◽  
Target Volume ◽  
Target Coverage ◽  
Imrt Plan ◽  
Intensity Modulated ◽  
3D Conformal Radiotherapy ◽  
Dosimetric Study

AbstractPurposeThis is a dosimetric study to compare the feasibility of carotid artery sparing as a primary objective, as well as planning target volume coverage and dose to spinal cord as a secondary objective, by using 3D conformal radiotherapy (3DCRT) and intensity-modulated radiotherapy (IMRT) for patients with early glottis cancer.Patients and methodsSix patients who had been treated for early stage glottic carcinoma (stage T1-2 N0M0) were included in this study. All patients were immobilised in the supine position with a thermoplastic mask and treatment planning computed tomography scans were obtained from the top of the skull to the top of aortic arch with a 3-mm slice thickness. Two plans were created for every patient, one using 3DCRT and the second using IMRT. Comparison between the two plans was undertaken and analysis was made regarding the dose to the carotids arteries, target coverage and doses to the organs at risk.ResultsFor target coverage, theV95%for both plans was the same with no significant difference, hot spots were the highest in 3DCRT withp=0·002, the homogeneity index for IMRT plan was better than 3DCRT (p=0·0001). Regarding the dose to the carotids, it was significantly lower in the IMRT plan compared with the 3DCRT plan (p=0·01). The spinal cord dose was significantly higher in the IMRT plan.ConclusionIMRT significantly reduces the radiation dose to the carotid arteries compared with 3DCRT while maintaining clinical target volume coverage. Such a results assists in decreasing the incidence of radiation-induced carotid stenosis, thus improving the quality of life for patients.

Helical tomotherapy for advanced esophageal cancer improves target conformity and homogeneity: A comparison with fixed-field intensity-modulated radiotherapy

2015 ◽  
Vol 11 (3) ◽  
pp. 3146-3155
Author(s):  
Luhua Wang
Keyword(s):  
Esophageal Cancer ◽  
Field Intensity ◽  
Helical Tomotherapy ◽  
Intensity Modulated Radiotherapy ◽  
Matched Pair ◽  
Conformity Index ◽  
Target Coverage ◽  
Advanced Esophageal Cancer ◽  
Fixed Field ◽  
Intensity Modulated

Purpose: To evaluate the usefulness of helical tomotherapy (HT) in the treatment of advanced esophageal cancer (EC) and compare target homogeneity, conformity and normal tissue doses between HT and fixed-field intensity-modulated radiotherapy (ff-IMRT).Methods: In all, 23 patients with cT3-4N0-1M0-1a thoracic EC (upper esophagus, 9 patients; middle esophagus, 6; distal esophagus, 6 and esophagogastric junction, 2) who were treated with ff-IMRT (60 Gy in 30 fractions) were re-planned for HT and ff-IMRT with the same clinical require­ments. Comparisons were performed using the Wilcoxon matched-pair signed-rank test.Results: Compared with ff-IMRT, HT significantly reduced the homogeneity index for thoracic, upper, middle and distal ECs by 38%, 31%, 36% and 33%, respectively (P < 0.05). The conformity index was increased by HT for thoracic, upper and middle ECs by 9%, 9% and 18%, respectively (P < 0.05). Target coverage was improved by 1% with HT (P < 0.05). The mean lung dose was significantly reduced by HT for thoracic and upper ECs (P < 0.05). The V20 (volume receiving at least 20 Gy) and higher dose volumes of the lungs were decreased by HT in all cases, but the differences were significant for thoracic, upper and distal ECs (P < 0.05), with reductions of 2.1%, 3.1% and 2.2%, respectively. HT resulted in a larger lung V5 for thoracic, upper, middle and distal ECs, with increases of 3.5%, 1.5%, 7.2% and 3.2%, respectively. Heart sparing was significantly better with HT than with ff-IMRT in terms of the V30 and V40 for thoracic, upper, middle and distal ECs (P < 0.05).Conclusions: Compared to ff-IMRT, HT provides superior target coverage, conformity and homogeneity, with reduced the volume of high doses to the lungs and heart for advanced EC. HT may be a treatment option for advanced EC, especially upper EC.

A REVIEW OF IMAGE-GUIDED INTENSITY-MODULATED RADIOTHERAPY FOR SPINAL TUMORS

Neurosurgery ◽  
2007 ◽  
Vol 61 (2) ◽  
pp. 226-235 ◽  
Author(s):  
Yoshiya Yamada ◽  
D. Michael Lovelock ◽  
Mark H. Bilsky
Keyword(s):  
Spinal Cord ◽  
Intensity Modulated Radiotherapy ◽  
Spinal Tumors ◽  
Tumor Control ◽  
High Dose ◽  
Single Fraction ◽  
Image Guided ◽  
Intensity Modulated ◽  
Very High ◽  
Dose Radiation

Abstract OBJECTIVE A new paradigm for the radiotherapeutic management of paraspinal tumors has emerged. Intensity-modulated radiotherapy (IMRT) has gained wide acceptance as a way of delivering highly conformal radiation to tumors. IMRT is capable of sparing sensitive structures such as the spinal cord of high-dose radiation even if only several millimeters away from the tumor. Image-guided treatment tools such as cone beam computed tomography coupled with IMRT have reduced treatment errors associated with traditional radiotherapy, making highly accurate and conformal treatment feasible. METHODS This review discusses the physics of image-guided radiotherapy, including immobilization, the radiobiological implications of hypofractionation, as well as outcomes. Image-guided technology has improved the accuracy of IMRT to within 2 mm of error. Thus, the marriage of image guidance with IMRT (IG IMRT) has allowed the safe treatment of spinal tumors to a high dose without increasing the risk of radiation-related toxicity. With the use of near real-time image-guided verification, very-high-dose radiation has been given for tumors in standard fractionation, hypofractionated, and single fraction schedules to doses beyond levels traditionally believed safe in terms of spinal cord tolerance. RESULTS Clinical results, in terms of treatment-related toxicity and tumor control, have been very favorable. With follow-up periods extending beyond 30 months, tumor control rates with single fraction IG IMRT (1800–2400 cGy) are in excess of 90%, regardless of histology, and without serious sequelae such as radiation myelopathy. Patients also report correspondingly high rates of palliation. Excellent results, both in terms of tumor control and minimal toxicity, have been consistently reported in the literature. CONCLUSION IG IMRT represents a significant technological advance. Paraspinal IG IMRT is proof of principle, making it possible to give very-high-dose radiation within close proximity to the spinal cord. By reducing treatment-related uncertainties, margins around tumors can be shortened, thereby reducing the volume of normal tissue that must be irradiated to tumoricidal doses, reducing the likelihood of toxicity. Similarly, higher doses of radiation can be administered safely, improving the likelihood of eradication. Dose escalation can be done to increase the likelihood of tumor cell kill without increasing the dose given to nearby sensitive structures.

scholarly journals Volumetric Modulated Arc Therapy for Head and Neck Cancer: A Dosimetric and Treatment Planning Comparison with Intensity Modulated Radiotherapy Techniques

2021 ◽  
Author(s):  
Brijesh Goswami ◽  
Suresh Yadav ◽  
Rakesh Kumar Jain ◽  
Pradeep Goswami
Keyword(s):  
Head And Neck Cancer ◽  
Head And Neck ◽  
Neck Cancer ◽  
Intensity Modulated Radiotherapy ◽  
Patient Comfort ◽  
Conformity Index ◽  
P Value ◽  
Target Coverage ◽  
Treatment Technique ◽  
Intensity Modulated

Introduction: Traditional Intensity Modulated Radiotherapy (IMRT) techniques used many beam angles; the result of this is significant increase in beam on time as well as Monitor Units (MU) also. Due to all of these there is a need of faster treatment modality to increase the patient comfort and lesser organ movement. Aim: To compare the triple arc RapidArc technique with nine field IMRT techniques for different head and neck cancer, focusing on target coverage and dose received by the Organs At Risk (OARs). Materials and Methods: Retrospectively, Computed Tomography (CT) datasets of 20 patients of Squamous Cell Carcinoma (SCC) of the Oro-pharynx and Hypo-pharynx treated during January 2019 to December 2019 were chosen for this study. For every patient, two different treatment plans were created, one by using the triple arc RapidArc technique and others by using nine fixed fields IMRT technique. For Planning Target Volume (PTV), the dose volume parameters D98% and D2% (dose received by the 98%, and 2% of the volume), homogeneity index, and Conformity Index (CI) were evaluated for dosimetric comparison. For OARs, the analysis included the mean dose, the maximum dose expressed as D2%. Additionally, the Beam On Time (BOT) and the number of MUs were analysed. A paired two-tailed t-test was performed to compare the RapidArc technique with the IMRT technique for radiotherapy treatment of different head and neck cancers. The p-value <0.05 was considered for the significance of statistical inferences. Results: Comparable target coverage and better sparing of OARs were achieved with the RapidArc technique in comparison to IMRT. Homogeneity and conformity were also in favour of the RapidArc plan. The dosimetric results with I’MatriXX measurements of RapidArc plans were similar to IMRT plans. All detector points passed 3 mm and 3% gamma criteria for IMRT plans and also for RapidArc plans. Conclusion: RapidArc is a faster and precise treatment technique. RapidArc provides better target coverage with good OARs sparing. Most significant change occurs in the number of MUs and treatment time, which is much lesser in RapidArc.

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