Tomotherapy: Implications on Daily Workload and Scheduling Patients Based on Three Years' Institutional Experience

Abstract

Helical tomotherapy (HT) was introduced at the Greater Poland Cancer Centre (GPCC) in April 2009. Retrospective analysis included data from the treatments performed for the first 656 patients treated with HT between May 2009 and May 2012 at the GPCC. In order to evaluate the implications on daily workload and scheduling of patients, stepwise regression and time analysis for each component of the overall treatment time, such as positioning, imaging, registration, and irradiation were performed. A detailed analysis included: (1) learning curves and optimized time needed for positioning and registration; (2) relation between irradiation time and parameters used for plan creation; and (3) average time of daily imaging. The irradiation component has the highest influence on the overall treatment time (R = 0.911). The lowest influence was observed for the imaging (R = 0.670). The learning curve for positioning was 7 months while the reduction of the average daily time needed for registration was observed even after two years. The irradiation time strongly depends on the planning parameters. Changing the pitch from 0.215 to 0.287 for pelvic cancer cases decreased the average daily beam-on time per patient by about 2 minutes. Similar changes for head and neck reduced this time by 1.3 minutes. The limitation in the usage of 1 cm field width only for complex cases, lower than 10 cm in the cranio-caudal direction, reduced the beam-on time per patient by 2 minutes. The average overall treatment time decreased from 21.5 minutes per patient in the first year of the HT usage to 13.8 minutes per patient in current practice. Our current practice shows that for a group of patients including mainly those with pelvis and head and neck cancers, the HT treatment takes approximately 15 minutes per patient allowing 40 patients to be treated within 10 hours.

Kiedy korekcja manualna zwiększa dokładność rejestracji obrazu podczas pozycjonowania pacjentów z rakiem prostaty?

“…pitch) wynosił zawsze 0.287 oraz współczynnik modulacji (ang. modulation factor) mieścił się w zakresie od 2.3 do 2.7 (modalna wynosiła 2.4) [9]. Wszyscy pacjenci leczeni byli w ułożeniu na plecach z unieruchomieniem kolan i stóp (Combifix; CIVCO Radiotherapy, Coralville, IA, USA).…”

Modele opisujące obciążenie aparatów terapeutycznych w radioterapii – przegląd literatury

“…Badania przeprowadzone przez grupę poznańską z Wielkopolskiego Centrum Onkologii (WCO) potwierdziły wpływ długoterminowego efektu uczenia się na redukcję OTT [4]. W przypadku tego badania, OTT wyznaczony w pierwszym roku użytkowania aparatu tomoterapeutycznego wynosił 21 minut i 30 sekund i po trzech latach został zredukowany do 13 minut i 50 sekund.…”

“…liczby leczonych pacjentów każdego dnia, miesiąca oraz roku [4]. Przy założeniu, że każdego roboczego dnia udałoby się przeprowadzić leczenie choćby jednego pacjenta więcej, w skali roku daje to liczbę ok. 255 pacjentów.…”

Safety of adjuvant intensity-modulated postoperative radiation therapy in endometrial cancer: Clinical data and dosimetric parameters according to the International Commission on Radiation Units (ICRU) 83 report

“…22,23 One hour prior to the delivery of each fraction, the patients were instructed to empty their rectums and bladders and to drink 500 ml of water. MVCT was systematically performed.…”