ABSTRACT
Purpose: Setup errors are inherent in the process of daily radiation therapy (RT) delivery. Pelvic RT for rectal cancer is one of the body sites associated with the largest shift among other body sites. This study aimed to evaluate interfraction random and systematic errors and hence propose the optimum planning target volume (PTV) in patients with rectal cancer. Methods and Materials: Translational and angular isocenter displacements were retrospectively collected for 189 patients. Random and systematic errors were determined, and then the PTV margin was computed. Effect of positioning, body mass index (BMI), and type of immobilization were studied. Portal images before and after online correction were used to define PTV for no-daily image-guided radiotherapy (IGRT) and daily IGRT respectively. Results: Before the online correction, the systematic errors were 2.5, 2.8, and 3.0 mm for superior-inferior (SI), right-left (RL), and anterior-posterior (AP) directions, respectively, compared with 2.1, 1.7, and 1.8 mm after online correction. The random errors were 6.2, 7.4, and 8.2 mm in SI, RL, and AP, respectively, before online correction, compared with 4, 4.2, and 4.5 mm after online correction. The recommended PTV margin was 0.7 and 1.0 cm for daily IGRT and no-daily IGRT, respectively. The prone position and BMI >30 kg/m2 warrant higher margins in no-daily IGRT cases, 1.2 and 1.4 cm, respectively. Conclusions: The prone position, BMI >30 kg/m2, and belly board device are associated with larger daily setup errors warranting higher PTV margins for no-daily IGRT; however, that can be avoided by using daily IGRT.
ABSTRACT
BACKGROUND AND AIMS: Chronic diseases are the leading cause of death as well as disability worldwide. There is a little information about the prevalence of these diseases among Saudi elderly population. The aim of the study was to assess the role of gender as risk factor for chronic diseases among elderly patients seen at primary health care centers and identify the most common chronic comorbidities among the elderly. METHODS: A cross-sectional study was conducted by reviewing charts of elderly patients having chronic illnesses seeking consultation between January to December 2016. Based on WHO classification data for 19 chronic diseases were extracted using electronic charts of the patients. Chi-square test and logistic regression was used to access the gender as predictor for chronic illnesses with statistical significance was set at P < 0.05. RESULTS: The total number 319 elderly patients were included in the study after random sampling with a mean age of 75 ± 7 years. Around 83 (26%) of patients were severely obese (BMI >35) with a mean BMI of 30 ± 6.7. The most common chronic illnesses were cardiovascular diseases 229 (71.8%), dyslipidemia 183 (57.4%) and diabetes 179 (56.1%). The chronic respiratory and endocrine diseases were common among the elderly females (P value 0.004, P value < 0.001). The most significant problem among males was disease of genitourinary system. There was significant positive correlation of multimorbidity with number of times of consultation in a year (r = 0.442, P value < 0.001). CONCLUSION: The study concludes that females are more likely to have chronic diseases at elder age than males. However, disease of the genitourinary system was significantly higher among male elderly. Multimorbidity significantly increased the need for frequent visits to the hospital.
