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SU‐E‐J‐55: End‐To‐End Effectiveness Analysis of 3D Surface Image Guided Voluntary Breath‐Holding Radiotherapy for Left Breast
Author(s) -
Lin M,
Feigenberg S
Publication year - 2015
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.4924142
Subject(s) - end to end principle , medical physics , radiation therapy , medicine , right breast , medical imaging , nuclear medicine , radiology , computer science , breast cancer , artificial intelligence , cancer
Purpose To evaluate the effectiveness of using 3D‐surface‐image to guide breath‐holding (BH) left‐side breast treatment. Methods Two 3D surface image guided BH procedures were implemented and evaluated: normal‐BH, taking BH at a comfortable level, and deep‐inspiration‐breath‐holding (DIBH). A total of 20 patients (10 Normal‐BH and 10 DIBH) were recruited. Patients received a BH evaluation using a commercialized 3D‐surface‐ tracking‐system (VisionRT, London, UK) to quantify the reproducibility of BH positions prior to CT scan. Tangential 3D/IMRT plans were conducted. Patients were initially setup under free‐breathing (FB) condition using the FB surface obtained from the untaged CT to ensure a correct patient position. Patients were then guided to reach the planned BH position using the BH surface obtained from the BH CT. Action‐levels were set at each phase of treatment process based on the information provided by the 3D‐surface‐tracking‐system for proper interventions (eliminate/re‐setup/ re‐coaching). We reviewed the frequency of interventions to evaluate its effectiveness. The FB‐CBCT and port‐film were utilized to evaluate the accuracy of 3D‐surface‐guided setups. Results 25% of BH candidates with BH positioning uncertainty > 2mm are eliminated prior to CT scan. For >90% of fractions, based on the setup deltas from3D‐surface‐trackingsystem, adjustments of patient setup are needed after the initial‐setup using laser. 3D‐surface‐guided‐setup accuracy is comparable as CBCT. For the BH guidance, frequency of interventions (a re‐coaching/re‐setup) is 40%(Normal‐BH)/91%(DIBH) of treatments for the first 5‐fractions and then drops to 16%(Normal‐BH)/46%(DIBH). The necessity of re‐setup is highly patient‐specific for Normal‐BH but highly random among patients for DIBH. Overall, a −0.8±2.4 mm accuracy of the anterior pericardial shadow position was achieved. Conclusion 3D‐surface‐image technology provides effective intervention to the treatment process and ensures favorable day‐to‐day setup accuracy. DIBH setup appears to be more uncertain and this would be the patient group who will definitely benefit from the extra information of 3D surface setup.