Evaluation of lung dose correction methods for photon irradiations of thorax phantoms

Comparisons between three different techniques by which the boost dose was delivered to the tumor bed were carried out , aiming to present the best technique of treatment for right breast cancer patients.In this study, ten right sided breast cancer computed tomography (CT) scans were selected for ten early right breast cancer patients. We made three different treatment plans for each patient CT using three different irradiation techniques to deliver a prescribed boost dose of 10 Gy in 5 fractions to the boost PTV. In the first technique, two tangential photon beams were used, in the second technique we, two oblique photon beams were used and in the third technique, a single electron beam was used. The comparative analyses between the three techniques were performed by comparing the boost PTV- dose volume histograms (DVHs), the ipsilateral breast (right breast) DVHs, the ipsilateral lung (right lung) DVHs and the heart DVHs of the three techniques for each patient. Furthermore the dose that covering 100% , 95% of the volume (D100% , D95%) and the volume covered by 95% of the dose (V95%)ofÂ the boost PTV of all techniques, were calculated for each patient to investigate the dose coverage of the target.Results showed that there were variations of the dose received by tumor bed, right breast and OARs depending on the technique used and the target location and size. A decrease of D100% than 90% of the prescribed dose was observed with the 3rd technique for patients 8, 9 and 10, and was observed with the 2nd technique for patient 5. A reduction of right breast dose was observed when the 3rd technique was use in comparison with the 1st and the 2nd techniques for patients 1, 2, 3, 4, 6 and 8.Â Also reduction of right breast was observed when the 2nd technique used in comparison with 1st technique. An increase of lung dose was observed with the 3rd technique for patients 1, 2, 5 and 6, also was observed with 2nd technique in patient 3, 5 and 7. A decrease of lung dose was observed with the 1st technique for patients 2, 4, 5, 6, 7, 8 and 9An individualized treatment, several plans using different irradiation techniques should be developed for each patient individually to reach the best boost PTV dose coverage with minimal OARsâ€™ dose.Â

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P2.01-47 Ipsilateral Lung Dose Constraints Predict Radiation Pneumonitis Better Than Conventional Ones in NSCLC Patients Treated with RCT

Journal of Thoracic Oncology ◽

10.1016/j.jtho.2019.08.1390 ◽

2019 ◽

Vol 14 (10) ◽

pp. S657

Author(s):

E. Korkmaz Kıraklı ◽

S. Erdem ◽

E. Erim ◽

D. Yalman

Keyword(s):

Radiation Pneumonitis ◽

Lung Dose ◽

Ipsilateral Lung ◽

Dose Constraints ◽

Nsclc Patients ◽

Better Than

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Use of Continuous Positive Airway Pressure (CPAP) to Limit Diaphragm Motion—A Novel Approach for Definitive Radiation Therapy for Inoperable Pleural Mesothelioma: A Pilot Study

Biology ◽

10.3390/biology10080711 ◽

2021 ◽

Vol 10 (8) ◽

pp. 711

Author(s):

Assaf Moore ◽

Marc J. Kindler ◽

Aaron Max Allen

Keyword(s):

Pilot Study ◽

Static Field ◽

Normal Lung ◽

Pleural Mesothelioma ◽

Lung Dose ◽

Lung Inflation ◽

Novel Approach ◽

Recent Developments ◽

Ct Simulation ◽

Dose Constraints

Malignant pleural mesothelioma (MPM) is a deadly disease and radiotherapy (RT) plays an important role in its management. Recent developments in technique have made it is possible to deliver RT to MPM in the intact lung. However, it is imperative to reduce normal lung doses. We present a pilot study examining the use of CPAP and VMAT radiotherapy to reduce toxicity when treating MPM, involving three consecutive patients with MPM, not amenable to surgery, who were treated according to Helsinki committee approval. Patients were simulated using four-dimentional CT simulation with the assistance of CPAP lung inflation, then were treated using both IMRT and VMAT techniques. Radiation lung dose was optimized based on accepted lung dose constraints. Patients were followed for toxicity as well as local control and survival. Results: Three patients were treated with CPAP-based IMRT treatment. These patients tolerated the treatment and DVH constraints were able to be met. The comparison plans among the four VMAT arcs and the IMRT static field treatment were able to accomplish the treatment planning objectives without significant advantages with either technique. The treatment combined with CPAP reduced the normal lung dose in MPM patients with intact lungs. This technique is worthy of further investigation.

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