Assessment of Palliative Care in Lung Cancer in Turkey.

OBJECTIVE: To investigate the symptoms of lung cancer in Turkey and to evaluate approaches to alleviate these symptoms. SUBJECTS AND METHODS: This study included 1,245 lung cancer patients from 26 centers in Turkey. Demographic characteristics as well as information regarding the disease and treatments were obtained from medical records and patient interviews. Symptoms were evaluated using the Edmonton Symptom Assessment Scale (ESAS) and were graded on a scale between 0 and 10 points. Data were compared using the χ2, Student t, and Mann-Whitney U tests. Potential predictors of symptoms were analyzed using logistic regression analysis. RESULTS: The most common symptom was tiredness (n = 1,002; 82.1%), followed by dyspnea (n = 845; 69.3%), appetite loss (n = 801; 65.7%), pain (n = 798; 65.4%), drowsiness (n = 742; 60.8%), anxiety (n = 704; 57.7%), depression (n = 623; 51.1%), and nausea (n = 557; 45.5%). Of the 1,245 patients, 590 (48.4%) had difficulty in initiating or maintaining sleep. The symptoms were more severe in stages III and IV. Logistic regression analysis indicated a clear association between demographic characteristics and symptom distress, as well as between symptom distress (except nausea) and well-being. Overall, 804 (65.4%) patients used analgesics, 630 (51.5%) received treatment for dyspnea, 242 (19.8%) used enteral/parenteral nutrition, 132 (10.8%) used appetite stimulants, and 129 (10.6%) used anxiolytics/antidepressants. Of the 799 patients who received analgesics, 173 (21.7%) reported that their symptoms were under control, and also those on other various treatment modalities (dyspnea: 78/627 [12.4%], appetite stimulant: 25/132 [18.9%], and anxiolytics/antidepressants: 25/129 [19.4%]) reported that their symptoms were controlled. CONCLUSION: In this study, the symptoms progressed and became more severe in the advanced stages of lung cancer, and palliative treatment was insufficient in most of the patients in Turkey.

Turkish pediatric residents' knowledge, perceptions, and practices of blood culture sampling.

INTRODUCTION: Pediatrics is one of the medical specialties in which blood cultures for bloodstream infections are performed very frequently. This study aimed to evaluate pediatric residents' knowledge and perceptions of blood culture sampling. MATERIAL AND METHODS: Between June 2019 and September 2019, a questionnaire comprising 20 questions about blood culture sampling was sent via email to participants who were pediatric residents at five different hospitals in Turkey. There were 11 true/false and nine multiple-choice questions that assessed three aspects of culture sampling: indications, sampling practice and knowledge, and contamination. The percentage of correct answers was used to calculate an overall score and subsection scores. RESULTS: A total of 132 pediatric residents [102 (77%) female] with a mean age of 28.3±2.8 years completed the questionnaire. Forty-five (35%) were in their 1st year of residency. Sixty (46%) participants reported that they had not performed blood culture sampling in the last week. There was a negative relationship between years in training and the number of cultures performed (Kendal's tau-b=-0.297, p<0.001). The overall median score was 65 (range, 35-90) and it seemed to increase with years of training. The lowest median score was in the contamination subscale and only one (0.76%) participant correctly answered all questions concerning contamination. CONCLUSION: Residents who obtained the majority of blood cultures had the lowest knowledge levels. Therefore, it is evident that the knowledge levels of pediatric residents must be increased in order to improve blood culture sampling practices in centers where they perform blood culture sampling.

Linac-integrated kV-cone beam CT polymer gel dosimetry.

X-ray CT polymer gel dosimetry (PGD) remains a promising tool for three dimensional verification of high-dose treatment deliveries such as non-coplanar stereotactic irradiations. Recent demonstrations have shown a proof-of-principle application of linac-integrated cone beam CT-imaged (LI-CBCT) PGDs for 3D dose verification. LI-CBCT offers advantages over previous CT based PGD, including close to real-time imaging of the irradiated dosimeter, as well as the ability to maintain the dosimeter in the same physical location for irradiation and imaging, thereby eliminating spatial errors due to dosimeter re-positioning for read-out that may occur for other systems. However the dosimetric characteristics of a LI-CBCT PGD system remain to be established. The work herein determines the dosimetric properties and critical parameters needed to perform cone beam PGD. In particular, we show that imaging the dosimeter 20-30 min post irradiation offers excellent recovery of maximum polymerization yield ([Formula: see text]90%), averaging with as few as 10 image averages can provide ∼90% gamma pass rates (3%, 3 mm) as compared to treatment planning, and that eliminating outlier averaging points can improve the precision and signal to noise ratio of resultant images. In summary, with appropriate methodology LI-CBCT PGD can provide dosimetric data capable of verification of complex high dose radiation deliveries in three dimensions and may find use in commissioning and validation of novel complex treatments.

Diuretics, plasma brain natriuretic peptide and chronic obstructive pulmonary disease.

BACKGROUND: Brain natriuretic peptide (BNP) is associated with increased myocardial stretching. This study aims to assess the effect of mild diuretics on plasma BNP levels in patients with an acute exacerbation of chronic obstructive pulmonary disease (COPD) who have high plasma concentrations of BNP. METHODS: Thirty consecutive patients with an acute exacerbation of COPD without any clinical evidence of cor pulmonale who had elevated plasma BNP concentrations (group 1) and 15 patients with stable COPD as controls (group 2) participated in this study. A mild diuretic treatment in addition to the standard treatment for an acute attack of COPD was randomised to 15 patients in group 1 (group 1A). The remaining patients in group 1 only took standard treatment for acute COPD exacerbation (group 1B). Plasma BNP concentrations were measured on admission and repeated on the 5th and 10th days. RESULTS: There was a significant decrease in plasma BNP concentrations, more striking in group 1A than 1B. Both in group 1A and 1B, the fall in plasma BNP concentrations was independent of either presence or absence of right ventricular dysfunction on echo evaluation. CONCLUSION: Adding mild diuretics to the standard treatment for an acute attack of COPD may rapidly reduce plasma BNP levels in COPD patients with acute exacerbations who have high plasma BNP levels without any clinical evidence of cor pulmonale.

Tracheopathia osteoplastica associated with iron deficiency anemia.

Tracheopathia osteoplastica (TPO) is a benign disease of trachea characterised by numerous cartilaginous or bony structures protruding into tracheobronchial lumen. We report a case of a 85-year-old male patient in whom tracheopathia osteoplastica was diagnosed incidentally during bronchoscopy which was missed on chest computed tomography examination. The patient also had iron deficiency anemia, the cause of which was not identified. We review TPO and discuss the associated abnormalities reported in the literature.

Sci-Thur AM: Planning - 05: Lung SBRT: Dosimetric accuracy of the Analytical Anisotropic Algorithm (AAA) for 6MV FFF RapidArc planning.

PURPOSE: Stereotactic Body Radiation Therapy (SBRT) requires the delivery of a high biologically effective dose in only a few fractions. These large doses per fraction can necessitate long treatment times. The Varian Truebeam is capable of RapidArc delivery and also has the optional Flattening Filter Free (FFF) modes which greatly increase the dose rate. We have commissioned the 6MV FFF beam (1400 MU/min) for RapidArc lung SBRT, and verified heterogeneous dose calculations with Monte Carlo (MC). METHODS: The standard commissioning data was acquired for Varian's Analytical Anisotropic Algorithm (AAA) beam model. Measurements were acquired with the IBA Blue Phantom, using the CC13 and CC01 ion chambers and PTW diode. MLC-defined fields were also acquired for model verification. The Dosimetric Leaf Gap (DLG) was measured and then optimized using RapidArc lung SBRT plans, matching Eclipse with ion chamber measurements. Heterogeneous dose calculations were independently verified using MC. RESULTS: There were some discrepancies regarding leaf transmission and penumbra, but the AAA model was generally well within 2% and 2 mm. A nominal DLG value of 1.6 mm was chosen. A representative lung SBRT case utilizing FFF RapidArc was calculated with MC. For the high dose region, 99% matched Eclipse within 3% and 3 mm. The mean dose difference of the PTV was 0.7%. CONCLUSIONS: Although we have observed some minor infield discrepancies between the AAA and Monte Carlo calculations in heterogeneous media, the Eclipse AAA is reasonably accurate for complex FFF, RapidArc, SBRT lung planning.

WE-E-BRB-09: A GPU-Based Monte Carlo QA Tool for IMRT and VMAT.

PURPOSE: To develop a GPU-based Monte Carlo (MC) 3D dosimetry quality assurance (QA) tool employing patient geometry and actual delivery information. METHODS: First, we generate fluence maps at all beam angles from the initial treatment plan. A GPU-based MC dose engine, gDPM, is employed for the secondary dose calculation (SDC) on patient CT. This SDC is used to verify the TPS plan dose (PD) accuracy. Before the 1st treatment fraction, we deliver the treatment plan on a Linac without any phantom setup to obtain machine log files. With the log files, we extract actually delivered fluence maps at all beam angles and perform delivered dose calculation (DDC) using gDPM. The difference between DDC and SDC indicates possible errors in data transferring and machine delivery. Lastly, the comparison between DDC and PD shows the accumulative errors from all the possible sources. Moreover, a web application for this QA tool is developed for clinical use. We have tested this QA tool on 6 patients, 4 VMAT and 2 IMRT patients. We reported mean gamma values and passing rates inside the 20% isodose line; DVH plot and dose difference matrix are also documented. RESULTS: For all six patients, the gamma passing rates within the 20% isodose line for SDC, DDC and PD comparisons are all higher than 95%. In the DVH plot, the three dose distributions were found to be very close. A typical IMRT or VMAT case takes less than one minute to run the whole QA tool. CONCLUSIONS: We have developed a GPU-based MC QA tool which can be used for efficient and easy IMRT and VMAT QA.

A Monte Carlo model of the Varian IGRT couch top for RapidArc QA.

The objectives of this study are to evaluate the effect of couch attenuation on quality assurance (QA) results and to present a couch top model for Monte Carlo (MC) dose calculation for RapidArc treatments. The IGRT couch top is modelled in Eclipse as a thin skin of higher density material with a homogeneous fill of foam of lower density and attenuation. The IGRT couch structure consists of two longitudinal sections referred to as thick and thin. The Hounsfield Unit (HU) characterization of the couch structure was determined using a cylindrical phantom by comparing ion chamber measurements with the dose predicted by the treatment planning system (TPS). The optimal set of HU for the inside of the couch and the surface shell was found to be respectively -960 and -700 HU in agreement with Vanetti et al (2009 Phys. Med. Biol. 54 N157-66). For each plan, the final dose calculation was performed with the thin, thick and without the couch top. Dose differences up to 2.6% were observed with TPS calculated doses not including the couch and up to 3.4% with MC not including the couch and were found to be treatment specific. A MC couch top model was created based on the TPS geometrical model. The carbon fibre couch top skin was modelled using carbon graphite; the density was adjusted until good agreement with experimental data was observed, while the density of the foam inside was kept constant. The accuracy of the couch top model was evaluated by comparison with ion chamber measurements and TPS calculated dose combined with a 3D gamma analysis. Similar to the TPS case, a single graphite density can be used for both the thin and thick MC couch top models. Results showed good agreement with ion chamber measurements (within 1.2%) and with TPS (within 1%). For each plan, over 95% of the points passed the 3D gamma test.

Monte Carlo calculation of dose distribution in early stage NSCLC patients planned for accelerated hypofractionated radiation therapy in the NCIC-BR25 protocol.

The dosimetric consequences of plans optimized using a commercial treatment planning system (TPS) for hypofractionated radiation therapy are evaluated by re-calculating with Monte Carlo (MC). Planning guidelines were in strict accordance with the Canadian BR25 protocol which is similar to the RTOG 0236 and 0618 protocols in patient eligibility and total dose, but has a different hypofractionation schedule (60 Gy in 15 fractions versus 60 Gy in 3 fractions). A common requirement of the BR25 and RTOG protocols is that the dose must be calculated by the TPS without tissue heterogeneity (TH) corrections. Our results show that optimizing plans using the pencil beam algorithm with no TH corrections does not ensure that the BR25 planning constraint of 99% of the PTV receiving at least 95% of the prescription dose would be achieved as revealed by MC simulations. This is due to poor modelling of backscatter and lateral electronic equilibrium by the TPS. MC simulations showed that as little as 75% of the PTV was actually covered by the 95% isodose line. The under-dosage of the PTV was even more pronounced if plans were optimized with the TH correction applied. In the most extreme case, only 23% of the PTV was covered by the 95% isodose.