Patterns of CT lung injury and toxicity after stereotactic radiotherapy delivered with helical tomotherapy in early stage medically inoperable NSCLC

To evaluate toxicity and patterns of radiologic lung injury on CT images after hypofractionated image-guided stereotactic body radiotherapy (SBRT) delivered with helical tomotherapy (HT) in medically early stage inoperable non-small-cell lung cancer (NSCLC)

Radiotherapy for inoperable non-small cell lung cancer using helical tomotherapy

Aim. To investigate the impact of tomotherapy on the dose delivered to the lungs and other normal tissues. Material and methods. From February 2008 to May 2009, 35 patients with stage II-IA/IIIB non-small cell lung cancer were treated with helical tomotherapy at the S. Camillo-Forlanini Hospital. For our study we selected 20 patients who underwent chemotherapy followed by sequential radiotherapy. The planning target volume was delineated using planning CT scan and FDG-PET. The mean prescribed radiation dose was 67.5 Gy delivered in 30 fractions at a dose of 2.25 Gy per fraction. Results. Median follow-up was 12.3 months. All patients developed acute esophageal toxicity, 15 of RTOG grade 1 and 5 of RTOG grade 2. At first follow-up 15 patients presented stable disease or partial response, 4 patients presented complete response, and 1 patient presented disease progression. Conclusions. Helical tomotherapy is useful to achieve dose-per-fraction escalation without increasing the treatment-related morbidity. Our results applying dose escalation were encouraging considering that we delivered doses that may be difficult to achieve with 3-dimensional treatments with no excessive complication rates

Deep learning method for tomotherapy delivery quality assurance: prediction of three-dimensional dose distribution and performance evaluation on phantom

High-tech radiotherapy capable to provide complex dose delivery modalities is one of the most important treatment modalities for cancer patients, making essential to evaluate with accuracy the clinical machine performances and the quality of the treatment plans [1–3]. The operation of Delivery Quality Assurance (DQA) is repetitive and involving both workforce and Linac bunker occupational time. To work around this problem, we developed new deep neural network models capable of predicting passing rates a priori for Helical Tomotherapy (HT) DQA in 3D voxel-by-voxel dose prediction. In this paper we evaluated net performances, focusing on learning quality in function of specific machine parameters

Deep learning method for TomoTherapy Hi-Art: prediction three‐dimensional dose distribution

Purpose or Objective High-tech radiotherapy capable to provide complex dose delivery modalities is one of the most important treatment modalities for cancer patients, making essential to evaluate with accuracy the clinical machine performances and the quality of the treatment plans [1-3]. The operation of Delivery Quality Assurance (DQA) is repetitive and involving both workforce and Linac bunker occupational time. To work around this problem, we developed new deep neural network models capable of predicting passing rates a priori for Helical Tomotherapy (HT) DQA in 3D voxel-by-voxel dose prediction. In this paper we evaluated net performances, focusing on learning quality in function of specific machine parameters

Comparison of EPR occupational lifetime external dose assessments for Mayak nuclear workers and film badge dose data.

The Mayak worker cohort is one of the major sources of information on health risks due to protracted exposures to plutonium and external ionizing radiation. Electron paramagnetic resonance (EPR) measurements in tooth enamel in combination with personal dose monitoring can help to improve external dose assessment for this cohort. Here, the occupational lifetime external exposure was evaluated individually for 44 nuclear workers of three plants of the Mayak Production Association by EPR measurements of absorbed doses in collected tooth enamel samples. Analysis included consideration of individual background doses in enamel and dose conversion coefficients specific for photon spectra at selected work areas. As a control, background doses were assessed for various age groups by EPR measurements on teeth from non-occupationally exposed Ozyorsk residents. Differences in occupational lifetime doses estimated from the film badges and from enamel for the Mayak workers were found to depend on the type of film badge and the selected plant. For those who worked at the radiochemical processing plant and who were monitored with IFK film badges, the dose was on average 570 mGy larger than estimated from the EPR measurements. However, the average difference was found to be only -4 and 6 mGy for those who were monitored with IFKU film badges and worked at the reactor and the isotope production plant respectively. The discrepancies observed in the dose estimates are attributed to a bias in film badge evaluation