Objective: To know the current status of the clinical assessment tests used to evaluate Alzheimer’s disease (AD) and memory-related dementias in specific regions throughout Mexico. Design, patients and settings: Patients with objective memory impairment were subjected to a clinical survey in medical centers specializing in memory loss. Each patient’s consultation was conducted like a routine clinical practice. Patient’s data were recorded using an anonymous patient survey. The most prominent behavioral problems were recorded. Results: 1350 patients were tested, 65.19% female (n=880). Out of 1350 patients, 76.59% (n=1034) had been previously diagnosed with any kind of dementia. The most common diagnosis concerning cognitive impairment was AD (54.2%, n=560) and Vascular Dementia (VaD, 19.7%, n=204). Minimental State Examination (MMSE) was performed in all patients and the average score was of 18±7. Katz scale for Activities of Daily Living (ADL) was performed in 49.41% (n=667) of patients, Lawton and Brody scale for Instrumental activities of daily living (IADL) in 35.78% (n=483), and Geriatric Depression Scale (GDS-Yesavage) in 32.89% (n=444). The most prominent behavioral symptom was apathy (12.15%, n=164).The most frequent concomitant diseases were: high blood pressure in 52.3%, diabetes in 27.0% and Dyslipidemia in 23.4%. Conclusions: Through the assessment of clinical surveys throughout Mexico, it was found that the most common form of dementia is AD and it is followed by VaD. Commonly, the Katz, Lawton and Brody, and the GDS-Yesavage scales are clinical assessment tests that are the most commonly used. There are many differences in the use of tests to evaluate patients with dementia across Mexico. For the first time, we were able to identify tendencies in the assessment of dementias by Mexican physicians.
Purpose:
To implement a back‐projection algorithm for 2D dose reconstructions for in vivo dosimetry in radiation therapy using an Electronic Portal Imaging Device (EPID) based on amorphous silicon.
Methods:
An EPID system was used to calculate dose‐response function, pixel sensitivity map, exponential scatter kernels and beam hardenig correction for the back‐projection algorithm. All measurements were done with a 6 MV beam. A 2D dose reconstruction for an irradiated water phantom (30×30×30 cm3) was done to verify the algorithm implementation. Gamma index evaluation between the 2D reconstructed dose and the calculated with a treatment planning system (TPS) was done.
Results:
A linear fit was found for the dose‐response function. The pixel sensitivity map has a radial symmetry and was calculated with a profile of the pixel sensitivity variation. The parameters for the scatter kernels were determined only for a 6 MV beam. The primary dose was estimated applying the scatter kernel within EPID and scatter kernel within the patient. The beam hardening coefficient is σBH= 3.788×10−4 cm2 and the effective linear attenuation coefficient is µAC= 0.06084 cm−1. The 95% of points evaluated had γ values not longer than the unity, with gamma criteria of ΔD = 3% and Δd = 3 mm, and within the 50% isodose surface.
Conclusion:
The use of EPID systems proved to be a fast tool for in vivo dosimetry, but the implementation is more complex that the elaborated for pre‐treatment dose verification, therefore, a simplest method must be investigated. The accuracy of this method should be improved modifying the algorithm in order to compare lower isodose curves.
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