A comparative study between open-face and closed-face masks for head and neck cancer (HNC) in radiation therapy.

AIM: To determine the setup reproducibility in the radiation treatment of Head and Neck (HN) patients using open face head and shoulder masks (OHSM) with customized headrest (CHR) versus standard closed head and shoulder masks (CHSM) and to determine the patient's level of comfort and satisfaction for both masks. METHODS: Forty patients were prospectively randomized into two groups using simple random sampling. Group 1 was assigned with CHSMs, immobilized with a standard HR (SHR) while Group 2 was assigned with OHSMs, and immobilized with CHR. Cone beam computed tomography (CBCT) was taken the first 3 days, followed by weekly CBCT (prior treatment) with results registered to the planning CT to determine translational and rotational inter-fraction shifts and to verify accuracy. Mean (M) and standard deviation (SD) of the systematic and random setup errors of the 2 arms in the translational and rotational directions were analyzed, using Independent t-test and Mann-Whitney U test. Patient comfort was measured using a Likert questionnaire. RESULTS: The vertical, lateral, longitudinal and Z/roll rotational shifts were not significantly different between the two masks. X/yaw and Y/pitch rotational shifts were significantly greater in Group 2 versus Group 1, for both systematic (p = 0.009 and 0.046, respectively) and random settings (p = 0.016 and 0.020) but still within three degrees. Patients reported higher neck and shoulder comfort (p = 0.020) and overall satisfaction (p = 0.026) using the OHSM with the CHR versus the CHSM with the SHR during CT simulation. CONCLUSION: Open masks provide comparable yet comfortable immobilization to closed masks for HN radiotherapy.

Effect of Body Mass Factors on Setup Displacement in Gynecologic Tumors and Subsequent Effect on PTV Margins.

Purpose: This study aimed to analyze the effect of body mass factors (BMFs) on setup errors in gynecologic tumors, and whether the planned tumor volumes (PTVs) are adequate for obese patients. Methods: This was a retrospective study of 46 consecutive female patients with gynecologic tumors who were treated with volumetric modulated arc therapy. Setup accuracy was verified using daily cone beam computed tomography. Accuracy was determined for each fraction by testing 2 different PTVs (cutoff I = ≤0.7 cm; cutoff II = ≤1.0 cm). A pooled analysis was conducted to test the association between accuracy levels (within vs beyond PTV) and the mean and variance of body mass index (BMI), umbilical (UC), and hip circumference (HC). A receiver operating characteristics curve analysis was carried out to test the sensitivity of BMI, UC, and HC in predicting inaccurate setup. Results: A significant association between BMFs and level of accuracy was observed in the lateral and vertical directions, but not in the longitudinal direction. In the lateral direction, inaccurate setups were associated with a greater BMI (mean difference: ∼3.50 kg/m2; P = .001), UC (∼10 cm), and HC (∼8 cm) compared with accurate setups (P < .001). With respect to the vertical direction, inaccurate setups (>0.7 cm margin [cutoff I]) were associated with a greater BMI (mean difference = 7.4 kg/m2; P = .001), UC (5.3 cm; P < .001), and HC (16.0 cm; P < .001) with reference to accurate setups. The receiver operating characteristics curve analysis showed that a BMI >31.4 kg/m2 was predictive for inaccurate setup in the vertical direction with 90.0% sensitivity with respect to cutoff I. Furthermore, a BMI >30.3 kg/m2 was predictive for inaccurate setup in the lateral direction with 92.5% sensitivity with respect to cutoff II. Conclusions: The accuracy of radiation therapy setups for gynecologic tumors is highly sensitive to patients' BMI, notably in the lateral and vertical directions. We suggest that daily cone beam computed tomography should be applied on patients with a BMI >30.3 kg/m2, using customized protocols that are lower in dose and comparable in image quality.

A comparison between two different immobilization devices for radiation therapy treatment of pelvic cancer using VMAT.

OBJECTIVES: To assess setup reproducibility of low kneefix with feetfix (LKF-FF) system and its operator-reported convenience by reference to low dual leg positioner (LDLP), among patients treated with pelvic radiotherapy. METHODS: A retrospective controlled trial was carried out at the radiotherapy unit. It included patients who underwent radical radiotherapy to the pelvis using VMAT, and who benefitted from LDLP (N = 30) or LKF-FF (N = 30) immobilization system. Average absolute shifts (AAS) and total vector errors (TVE) were computed and compared between the two systems, using translational (lateral, longitudinal and vertical) and rotational (X, Y and Z planes) directions. Accuracy rates were computed on pooled data including 1529 VMAT images, 819 in LDLP and 710 in LKF-FF groups, using different cutoffs. Radiotherapists' subjective assessment of the device's ease of setup, handling, cleaning, and storage, and patient comfort was carried out comparatively between the two devices. RESULTS: No statistically significant difference was observed between the two systems in systematic settings, while LKF-FF outperformed LDLP in random settings; notably in vertical translation and X and Z rotational shifts. Analysis of TVEs showed significant decrease in rotational TVE in LKF-FF group (mean=1.38° versus 2.38, p = 0.003) by reference to LDLP, respectively; however, both systems had comparable translational TVE (p = 0.590). In pooled analysis, LKF-FF enabled an overall increase in setup accuracy rates in rotational directions by up to 15% and 19% at ±1° and ±2° accuracy levels, respectively (p<0.05). Subjective assessments showed that the two immobilization systems were comparable regarding all investigated dimensions; however, the overall radiotherapists' preference leaned toward LDLP. CONCLUSION: The newly implemented LKF-FF system outperformed LDLP in terms of setup reproducibility, notably in rotational directions, where it enhanced setup accuracy rates by up to 19%. Long-term use of LKF-FF may improve the users' satisfaction.

Comparing Accuracy of Thermoplastic Mask versus Commercial Bra for the Immobilization of Pendulous Breast During Radiation Therapy Treatment: A Retrospective Cohort Study.

PURPOSE: This study aimed to compare thermoplastic mask with bra in terms of setup reproducibility and immobilization of pendulous breasts during radiation therapy (RT). METHODS AND MATERIALS: Forty-two female patients with breast cancer treated with either intensity modulated RT or 3-dimensional conformal RT were retrospectively reviewed. Of these, 21 benefited from thermoplastic mask immobilization and 21 used a bra. Setup accuracy was evaluated using consecutive cone beam computed tomography/electronic portal imaging device sessions over the first 3 days before treatment (systematic setting), followed by weekly cone beam computed tomography/electronic portal imaging device (random settings), and compared with the reference image to calculate the corresponding translational shift (setup error) in the 3 planes. Average absolute shift values in both systematic and random settings were compared between the 2 groups. Accuracy was analyzed by comparing the percentage of pooled settings within ±0.05 and ±0.1 cm of the reference image. RESULTS: Compared with a bra, use of the mask was associated with a smaller longitudinal shift in systematic settings (difference in mean: 0.27 cm; P = .027; Mann-Whitney U test) and a lesser lateral shift in random setting (difference in mean: 0.19 cm; P = .005; Mann-Whitney U test). In the pooled systematic settings, the mask performed relatively better than the bra in the lateral and longitudinal planes, with no statistical significance. In pooled random settings, mask showed greater accuracy than bra in the lateral plane with 86.0% versus 58.9% accuracy at ±0.5 cm (P < .001) and 48.8% versus 21.7% accuracy at ±0.1 cm (P < .001), respectively. There was no significant difference in the incidence of radiodermatitis between the 2 groups. However, a hypofractionation regimen was associated with a lower incidence of radiodermatitis, and the severity of skin reactions was positively correlated with treatment dose (unstandardized regression coefficient: B = .001; correlation coefficient: r = .571; P < .001). CONCLUSIONS: Masks provide superior reproducibility compared with commercially available bras.

Site-Specific Education Using Digital Media to Improve Patient Understanding of the Radiotherapy Trajectory: An Interventional Study.

PURPOSE: The study assessed the effectiveness of a site-specific video educational material in improving patient understanding and confidence regarding radiation therapy trajectory. METHODS AND MATERIALS: A quasi experimental longitudinal pretest posttest study was conducted at a referral radiation therapy center from May 2020 to September 2020. It included 52 adult patients admitted for a first course radical radiation therapy. One generic and 6 site-specific (breast, pelvis, head and neck, brain, chest and abdomen, and bladder) animated cartoon videos were developed in house to provide concise overview of the overall patient's trajectory in radiation therapy, with full visual description of the procedures and specific preparation measures. A 14-item questionnaire was designed to assess pre- and postintervention levels of understanding and confidence of patients, with calculation of and an understanding and confidence score (UCS), range 0-14. RESULTS: The mean (standard deviation) UCS in pre- and postintervention was 9.36 (2.48) and 11.92 (1.34) out of 14, respectively, indicating a mean increase of 2.57 subsequent to the intervention (P < .001). The effect size was large with a Cohen's d = 1.01. Of the 14 dimensions explored, 8 were observed to have remarkable improvement, notably understanding the purpose of the tattoo mark, reason of daily or weekly imaging, and what to expect with radiation therapy. Participants with poor reading ability had greater increase in UCS (ΔUCS = 4.25 vs ≤2.33) and in 5 out of 8 dimensions with remarkable improvement. CONCLUSIONS: The use of digital educational material in radiation oncology meets the urgent need for providing patients with concise and site-specific information, while sparing extra hospital visits to meet education coordinators during the COVID-19 crisis. Additional studies are warranted to assess both the clinical and long-term effectiveness of the educational material, using a longitudinal controlled design.