SU-E-T-187: Clinical Use of the Software for the Automation of Treatment Field Parameters Verification Prior to Radiation Delivery.

PURPOSE: Verification of treatment field parameters by therapists take place prior to every or first fraction. Such verification or field timeout should be completely independent from record-and-verify system. It is performed manually via reading treatment parameters from linac screen and comparing them to treatment plan. We evaluate clinical use of software allowing automation of field timeout. METHODS: The program for automated timeout performs three tasks.Plan information is extracted from PDF printouts generated by Eclipse (Varian Medical Systems, Palo Alto, CA) treatment planning system. User selects patient, plan and field to be compared with the field moded-up at the linac. Information from the Varian (Varian Medical Systems) linac's screen is extracted using video signal splitter and VGA2USB converter (Epiphan Systems, Ottawa, CA). Image farther undergoes character recognition, which works reliably for 1X, Trilogy and 2100C linacs used in out tests.The plan and linac screen information are output to the computer screen and user is alerted if mismatch is observed. The software uses tolerances established in out clinic. The program also outputs auxiliary information, e.g. bolus, which is not well alerted by or can be omitted in the record and verify system. In the workflow tested, PDF printouts are uploaded for the software during second check and automatic timeout is performed for all treatments except v-sim and first fraction (of each treatment plan). RESULTS: The software has friendly user interface and is easily included in clinical work flow. With the error rate being extremely low, we don't have data yet to claim that automated timeout provides higher safety than manual; however, it definitely cuts timeout time to 2-3sec per fields versus 10sec, if done manually. CONCLUSIONS: Field timeout automation is practicable and fits well into clinical workflow. It improves patient throughput and is expected to improve patient safety. CONFLICT OF INTEREST: S. Kriminski and I. Lysiuk: provisional patent application is submitted to United States Patent and Trademark Office.

Clinical cough IV:what is the minimal important difference for the Leicester Cough Questionnaire?

BACKGROUND: The Leicester Cough Questionnaire (LCQ) is a valid, reproducible, responsive self-reported cough-specific health status measure. It has been used to assess overall efficacy of treatments for cough, but its threshold for clinical significance, or patient importance, is unknown. The aim of this study was to determine the minimal important difference (MID) of the LCQ for patients with chronic cough; this is the smallest change in quality-of-life score considered to be clinically meaningful. METHODS: The LCQ MID was first estimated by a multidisciplinary panel of experts who reviewed two cases of chronic cough. It was subsequently determined using a standardized method. Fifty-two patients with chronic cough of more than 8 weeks' duration attending a respiratory outpatient clinic were recruited. Participants completed the LCQ at initial evaluation and repeated the LCQ with four Global Rating of Change Questionnaires (GRCQ) more than 2 months later. The LCQ total score ranges from 3 to 21 and from 1 to 7 for physical, psychological and social domains; a higher score indicates a better health-related quality of life. The GRCQ, a 15-point scale scored between +7 (a great deal better) and -7 (a great deal worse), was used to record patient ratings of change in cough symptoms. The MID was defined as the change in LCQ health status corresponding to a small change in the GRCQ score. RESULTS: The mean (standard deviation) LCQ MID corresponding to a small change in the GRCQ score was 1.3 (3.2); the MIDs for domains were as follows: physical 0.2 (0.8), social 0.2 (1.1) and psychological 0.8 (1.5). This MID for LCQ total score was similar to that determined by the expert panel. The global rating of change scores correlated significantly with the change in LCQ total and domain scores (r=0.4-0.5; p<0.005). CONCLUSION: We have demonstrated that the LCQ MID is 1.3. The LCQ MID should aid clinicians and researchers to make meaningful interpretations of health-related quality-of-life data relating to chronic cough.

Induced sputum and other outcome measures in chronic obstructive pulmonary disease: safety and repeatability.

The forced expiratory volume in 1 sec (FEV1) is the most established outcome measure in chronic obstructive pulmonary disease (COPD). However, changes in FEV1 in response to treatment are small in relation to the repeatability of the measurement and there is increasing interest in other measures including markers of lower airway inflammation in induced sputum, assessment of symptoms and health status using visual analogue scores, and questionnaires. Little is known about the repeatability of these measures or the safety of sputum induction in COPD. We have assessed the safety of sputum induction in 61 subjects with moderate and severe COPD who participated in a placebo-controlled cross-over study The within-subject repeatability of sputum markers of airway inflammation, health status using the chronic respiratory disease questionnaire (CRQ) and symptom visual analogue scores (VAS) were estimated from the data obtained from before and after 2 weeks of treatment with placebo. Sputum induction was performed on 122 occasions and was successful resulting in a cytospin adequate to assess a differential cell count in 95% of inductions. The group mean (SEM) FEV1 was 1.09 (0.05)[41.6 (2.9)% predicted] and the mean (SEM) fall in FEV1 after sputum induction was 120 ml (6) and % fall 10.9% (0.55%). Seven inductions were stopped due to a fall in FEV1 >20% and at a further 13 visits the full sputum induction protocol was not completed due to development of symptoms. The reproducibility of measurements, calculated by the intra-class correlation coefficient, was relatively high for all indices measured (0.4-0.95) with the exception ofthe proportion of lymphocytes (0.15) and epithelial cells (0.3). The ICC for symptom scores and the CRQ domains ranged between 0.87 and 0.96. In conclusion, sputum induction is safe and the cell and fluid phase mediators repeatable in the investigation of airway inflammation in patients with COPD. VAS symptom scores and the CRQ are reproducible outcome measures in COPD.

Initial clinical experience with the Peacock intensity modulation of a 3-D conformal radiation therapy system.

Peacock is a 3-D conformal treatment planning and delivery system for conformal radiation therapy which delivers intensity-modulated fields. A group of 13 patients were treated between March and February, 1995. Patient age ranged from 10 to 74. Six of the patients had previously received radiation therapy. Target volume was from 2.5 to 70 cm3: all treatments were fractionated, using single table angle plan with 270 degrees of rotation. A removable invasive cranial screw fixation device was used in all cases. Treated isodose line averaged 85%; conformality index was better than 2, with 0-5% of critical structure volume exceeding dose limits. Setup time averaged 8 min per fraction: treatment time ranged from 10 to 80 min. There were two equipment failures in 200 fractions/1,000 gantry rotations. Patient position averaged about 1 mm within initial setup. Follow-up has revealed no complications from the radiation.