ABC | Volume 110, Nº2, February 2018

Original Article Rodrigues et al Practices in Myocardial Perfusion Scintigraphy Arq Bras Cardiol. 2018; 110(2):175-180 Table 1 – Quality index according to the demographic, professional and regional characteristics of nuclear medicine services (NMS) N Mean Median Standard deviation p value Brazilian region Southeast 34 5 5 1.044 0.750* South 17 4.76 5 1.200 West-Central 2 5.00 5 0.000 Northeast 8 4.50 4 0.926 North 2 4.50 4 0.707 Type of NMS Private 55 4.91 5 1.076 0.329 ƚ Public 8 4.50 5 0.756 University-affiliated Yes 7 5.57 5 0.78 0.046 ƚ No 56 4.77 5 1.04 > 3 nuclear physicians Yes 45 4.76 5 0.85 0.204 ƚ No 16 5.19 5 1.47 Complete multidisciplinary team Yes 12 5.33 5 0.98 0.030 ƚ No 51 4.75 5 1.03 Exclusive NMS Yes 19 4.86 5 0.956 ƚ No 44 5 * Independent-Samples Kruskal-Wallis test; ƚ Independent-Samples Mann-Whitney U test When assessing the amount of MPS performed monthly and its relation to the desirable QI (Table 2), we observed that institutions with QI ≥ 6 performed a statistically higher number of MPS than those that did not adopt at least six good practices (p = 0.043). When assessing the presence of each good practice in the 63 NMS (Table 3), the most frequently adopted by all were as follows: 1) do not use the thallium-stress protocol; 2) do not use the dual-isotope protocol; and consequently 3) do not use increased Tl-201 activities. Conversely, the least frequently adopted good practice was the use of the abbreviated stress‑only myocardial perfusion imaging, in only 6% of the NMS. Discussion The IAEA has been dedicated to promoting good practices in nuclear cardiology, undertaking the largest research about cardiological tests so far, by use of a cross-sectional study of global comprehensiveness called INCAPS, which evidenced that the adoption of good practices in NMS is highly heterogeneous in the continents. The NMS in Asia and Latin America showed the worst performance, with less than one quarter of the NMS achieving the desirable QI (≥ 6 good practices). 7 Information on the situation of the NMS in Brazil is scarce. After that research, the Brazilian Society of Nuclear Medicine, concerned with qualified practice, was one of the first entities to endorse the adoption of good practices in its guidelines, aimed at the continuous search for a reduction in radiation exposure (optimization). 10 Thallium-201 scintigraphy has unfavorable physical characteristics, such as low counting rate and long physical half-life, which are associated with a higher dose of radiation absorbed, being considered a second option to Tc‑99m‑sestamibi. The use of Tl-201 is strictly recommended for myocardial viability studies, but with the new devices with highly effective detectors, there is a renewed interest in ultrafast dual-isotope protocols that enable the use of low doses and conveniently allow performing the complete test in less than 30 minutes. 11 In our study, we observed that 100% of the NMS assessed used neither Tl-201 nor dual-isotope as the preferred protocol, which is a good practice also associated with the financial aspect, considering the lower cost of Tc-99m-sestamibi and its easy use, which involves a medication kit. Thus, currently the traditional protocols of one or two days still predominate. Conversely, the least frequently adopted good practice by the NMS in our study was the abbreviated stress‑only myocardial perfusion imaging . 12 Chang et al. 13 have demonstrated that it is safe to use a single stress phase, without rest, in normal tests from the perfusional and contractile function viewpoint, which facilitated the dynamics of the NMS 177