Image quality control as it applies to diagnostic Radiology is an effort to ensure that the diagnostic images produced are sufficiently provides adequate anatomical information for accurate diagnosis at the least possible exposure of radiation to the patient. The aim of this study was to determine the suitable range of kV and mAs at a constant FFD to produce skull radiographs of acceptable quality required by the Radiologist.  A locally made skull phantom with Perspex glass box and a real human skull from Anatomy department was used in this study. The phantom was placed on the X-ray table 120 cm from the X-ray tube head and two sets of exposures were made. First keeping mAs at 50 and varying the kV from 81-102 and the second keeping kV constant at 81 and varying the mAs from 32-80. Films were developed and 5 radiographs in each set were produced. A Raysafe Thin-X dose meter was fixed in front and at the back of the Phantom to determine the input and output dose respectively. The absorbed dose was calculated by the difference between input and output doses. The radiographs were assessed by a Radiologist to classify the image quality. The suitable exposure factors were found to be within the range of 81-85 kV with 50 mAs and 32-40 mAs with 81 kV to produce an acceptable quality skull radiograph. The absorbed dose varied from 1.451-3.503 mGy.  The optimum image quality was obtained with 81 kV and 32 mAs at FFD =120 cm with minimum absorbed dose of 1.451 mGy.

Distributed In recent years, the determination of suitable exposure factors in various X-ray examinations have been an issue of general interest to Radiographers, Radiologists and Medical Physicists forms a step towards a quantitative relation between the radiation and the effect they produce. It is known that X-rays are forms of electromagnetic radiation with higher energy and can penetrate the body to form an image on an X-ray film. Structures that are dense (such as bone) will appear white, air will be black and other structures will be shades of gray depending on density. A skull X-ray is a picture of bones surrounding the brain, including the facial bones, the nose and the sinuses (paranasal). It is the Radiological examination that involves exposing the head briefly to radiation to produce an image of the skull and the internal organs of the skull. An X-ray film is positioned against the head opposite the machine, which sends out a small dose of radiation. As the radiation penetrates the skull, it is absorbed in varying amounts by different skull tissues. The X-ray film records these differences to produce an image of the skull tissues structures. A skull X-ray can be used to define abnormalities of the skull such as fractures, tumors, bleeding, crack and so on. Skull radiography is a relatively high-dose examination and contributes significantly to the collective dose, making it a useful examination to find suitable exposure factors so as to minimize the exposure rate and the dose to which the patient is exposed. The patient doses in radiography primarily depend on the exposure factors i.e. potential difference (kVp), tube current (mA), time(s), the X-ray beam, Focal Film Distance (FFD) and the sensitivity of the organs and tissues that are irradiated during the radiation 

With Regards,
Sara Giselle
Associate Managing Editor
Journal of Medical Physics and Applied Scinces