Introduction: Nowadays, Imaging of the myocardial perfusion (MPI) using the single photon emission tomography (SPET) in the diagnosis of coronary artery disease, especially myocardial ischemia, is of great importance. In contrast to the coronary artery angiography, MPI is non-invasive, less expensive and more physiological. Unfortunately, this image is affected by the some artifacts. These artifacts lead to decrease image diagnostic accuracy and increase false positive cases. One of the most important effective artifacts is due to attenuation. These attenuation artifacts are caused by the left breast tissue in women, diaphragm in men and the chest wall in both sexes. Because of the inherent non- uniform attenuation map in the thorax region, this problem is very complex. Methods: The aim of this study is to correct attenuation artifact with a simple method that is available and very easy to use. In this study we used transmission scanning by 99mTc in the sequential views and an attenuation map was created.After attenuation correction of the original images with attenuation map, non corrected and corrected images were compared with angiography results to apply attenuation correction based on functional findings. Results: Results show that new artifacts are created and experiences of physicians in the impression of the images is critical. Finally, the sensitivity of images increased from 86.20% to 96.42%, the specificity decreased from 85.71% to 54.54% and the diagnostic accuracy decreased from 86% to 78%. Conclusion: Attenuation correction can produce new artifacts, which can influence the way scans are interpreted. It seems that attenuation correction of the images, need special experience. Lack of enough experience in attenuation correction techniques, can comprise the diagnostic accuracy of images.

Lithostratigraphy and biostratigraphy studies on the Sarvak Formation in type section (Tang-e Sarvak, Northwest of Behbahan) show that this Formation has 710 meter thicknesses that divided in to four lithostratigraphic units. The Sarvak Formation in type section rests on the Kazhdumi Formation conformably with gradational contact (black shales and black argillaceous limestone) and under the Gurpi Formation with disconformity boundary. In this study 8 genus and 9 species of planktonic foraminifera and 34 genera and 33 species of benthic foraminifera have been reported. Four biozones based on (wynd, 1965) and two biozone based on) Premoli Silva and Verga 2004) have been reported as follow; Four biozones based on Wynd 1965: 1-Favusella washitensis range Zone # 23, 2-‘ ’ Oligostegina’ ’ facies # 26, 3-Rudist debris # 24, 4-Nezzazata– Alveolinids Assemblage Zone # 25, Tow biozones based on Premoli Silva and Verga 2004: 1-Muricohedbergella planispira Zone, 2-Ticinella primula Zone. It can propose an Albian-Cenomanian age for Sarvak Formation based on these biozones and also it can recognize Albian-Cenomanian boundary on occurrence of Muricohedbergella planispira and Whiteinella sp. in lower part of this Formation.

Geirud formation deposits of Kalariz in the Eastern Alborz start with a relatively thick sequence of sandstone, shale, and red, white and brown colored siltstone changing into yellow dolomitic layers, fossiliferous limestone and shaly or marly limestone. This formation lies over Mila formation with a disconformity and covered transitionally by limestones of Mobarak formation. In the above mentioned sequence, numerous and various conodonts and brachiopods were identified. Based on the distribution of brachiopoda, two assemblage zones and based on the conodonts, four assemblage zones were recognized with Famennian and Strunian age. The first brachiopoda biozone, equivalent to the first and second conodont biozones, belongs to Early Famennian age (older than late crepida zone and romboidea to late trachytera zone) and the second Brachiopoda biozone which is equivalent to conodont biozone of number three and four has the late Famennian age (postera to late expansa zone and Praesulcata zone). Paleontological and stratigraphical evidence indicates that Frasnian sediments are absent in the study area.

The Ruteh Formation in Aru section, Central Alborz with a thickness of 151/5 meters consist of alternating dark gray limestone with intercalations dark gray shale.This Formation overlays by Doroud Formation and is disconformably overlain by the equivalent of Nessen Formation (Early Djulifian). The Ruteh Formation in study section can be subdivided into 3 informal members. In the present study, according to microfauna's investigated, the Ruteh Formation in the study area that indicate an early Djulfian age.

Elika Formation at the Tash section (300 m in Thickness) is one of the most complete sections in the eastern Alborz basin. Petrographic studies indicate that carbonate sediments of the Tash section could be divided into several groups of microfacies which has been formed in four sub-sedimentary environments, including: Tidal flat, Lagoon, Bar and Open marine. The absence of reef and resedimented facies indicates that the carbonate platform of the Elika Formation is similar to the recent Persian Gulf shelf (Ramp). Field and laboratory studies showed that the sediments were composed of four third-order depositional sequences.