Evaluating X-Ray based Medical Imaging Devices with Fuzzy Preference Ranking Organization Method for Enrichment Evaluations

X-rays are ionizing radiation of very high energy, which are used in the medical imaging field to produce images of diagnostic importance. X-ray-based imaging devices are machines that send ionizing radiation to the patient’s body, and obtain an image which can be used to effectively diagnose the patient. These devices serve the same purpose, only that some are the advanced form of the others and are used for specialized radiological exams. These devices have image quality parameters which need to be assessed in order to portray the efficiency, potentiality and negativity of each. The parameters include sensitivity and specificity, radiation dose delivered to the patient, cost of treatment and machine. The parameters are important in that they affect the patient, the hospital management and the radiation worker. Therefore, this paper incorporates these parameters into fuzzy PROMETHEE (Preference Ranking Organization Method for Enrichment Evaluation) multi-criteria decision theory in order to help the decision makers to improve the efficiency of their decision processes, so that they will arrive at the best solution in due course. Keywords—X-ray-based imaging devices; medical imaging; fuzzy PROMETHEE


INTRODUCTION
Medical imaging refers to the use of ionizing and nonionizing radiation to produce images of the internal parts of the body for diagnostic purposes [1].X-ray, which is the origin of medical imaging, was discovered in 1895 by Wilhelm Conrad Rontgen.Many medical imaging devices use X-rays to produce images of diagnostic value.The imaging devices include Computed Tomography (CT), Fluoroscopy, Conventional X-ray Machine, Mammography and Angiography [1].These devices are similar because they all use X-ray radiation, but they differ in the type of radiological examination to be carried out.The devices have certain parameters like effective dose delivered to the patient, sensitivity, specificity, duration of scan, radiation dose, and cost.These parameters affect the patient directly, and it will be very important if they are analyzed in order for the parties concerned to have a good understanding of the procedures, their benefits and risks.
Making decision of using which technique for a specific patient or buying an x-ray based machine for a hospital can be difficult because of the high number of criteria and the range of their possible values.Fuzzy PROMETHEE is a method which gives the ability to compare selected alternatives according to some given criteria.
In this paper, Fuzzy PROMETHEE was used to evaluate the mostly used radiological equipment utilizing X-ray by using their parameters including radiation dose and scan time.
Section 1 of this paper introduces the paper while Section 2 introduces the various X-ray based medical imaging devices.In Section 3, the methodology and application is explained, Section 4 shows the result, and lastly Section 5 concludes the study.

A. Conventional X-Ray Machine
This is the main device in most radiology departments, used to image internal structures.It is mainly dedicated to extremities, head, neck and abdominal region examinations.Indications include fractures of the limbs and skull, cervical spine and lumber vertebra exams, and abdomino-pelvic examinations.The main component of the X-ray machine is the Tube.The Tube consists of the anode, cathode, filament, glass envelope etc.The X-ray is produced when a current is passed through the filament, which results in heating the filament and electron production.These electrons are then accelerated to the anode target, where they become converted to X-ray and pass through a window to the object to be Xrayed.As the X-ray pass through the object, they hit a fluorescent cassette, which converts the X-ray into light, and a final image is produced after processing the cassette.X-ray imaging relies on the attenuation coefficient of the tissues and www.ijacsa.thesai.orgorgans in the body.This is the reason why some parts appear bright while others appear dark [2].

B. Angiography
This is a specialized radiological examination that employs a contrast medium to outline the blood vessels, such as the arteries and the veins.It is mainly used to check the arterial or venous supply to the head, upper and lower limbs and thorax.Typical example of the procedure includes cerebral angiogram, pulmonary angiogram, coronary angiogram, etc.
The contrast is injected via a catheter into the femoral artery or vein, or into the brachial artery or vein.Several X-ray images of the area of interest are acquired and stored in films or digital format on computers.The procedure is usually indicated for aneurysm, stenosis and coronary artery disease [3].

C. Computed Tomography (CT)
This is a technique in which tomographic images are produced by transmitting X-rays from an external source at several projection angles.This procedure is mostly used for anatomical localization and attenuation correction.CT uses a gantry containing the X-ray source and set of detectors, and also a bed where the patient lies during the examination.Axial images obtained from CT can be reformatted into coronal and sagittal, resulting to a 3D image set.CT is mostly used for tumors, brain and nervous system examination, urinary tract examination, and abdominal tumor [4].

D. Fluoroscopy
This imaging technique is used to obtain real-time images of a patient with the aid of a fluoroscope.It uses X-rays to obtain real-time (moving images) of the interval part of the body.Fluoroscope consists of a fluorescent screen with an Xray source between which the patient is placed.In modern fluoroscopes, the screen is connected to an X-ray beam condenser and a Charge -coupled device (CCD) video camera, which allows viewing or recording on an image monitor.Indications for fluoroscopy exams include special examinations like Hysterosalpingography (HSG), Intra-venous Urethrography (IVU), Barium studies, etc. Patient is exposed to a large amount of radiation, even if the dose used is minimal [5].

E. Mammography
This is a special device used to mage the breast.It has been very effective in the diagnosis of breast and axillary tumors.They use low energy X-ray to create images of the breast in both Medio-lateral and Cranio-caudal projections.These images are analyzed for any abnormal findings.Components include the tube, compression plate, cassette, breast support with grid, exposure button etc. Mammography has a limitation when it comes to women below the age of 30.It is suggested that women between the ages of 35-40 should undergo screening mammography at least once a year.During mammography procedure, the breast is slightly compressed between the two plates of the device for a few seconds.By so doing, all breast tissues are evaluated in 2 dimensions.3D image can be obtained with digital breast tomosynthesis [6].

III. METHODOLOGY AND APPLICATION
The PROMETHEE method alone was proposed by [7] and [8].The fuzzy PROMETHEE method allow the decision maker using fuzzy input data, which gives more flexibility to the decision maker while they compare alternatives in vague conditions.Application of this method was done by [9]- [15].
In the study conducted by [16], a detailed description of the fuzzy PROMETHEE method was given.In this study, we applied the same methodology for the evaluation of X-Ray based devices.
The most important parameters of the X-ray based medical imaging devices which include specificity, radiation dose, sensitivity, cost of devices and scan time are given in Table I as low bound, medium and upper.Choosing the parameters into three classes of low bound, medium and upper was done in order to apply triangular fuzzy numbers since the parameters of the alternatives are not crisp.We used normalization and then we transform them to the triangular fuzzy numbers (N, a, b) as shown in Table II.And then we used Yager index to see the magnitude of the parameters of the alternatives, which are fuzzy numbers.The linguistic scale of the importance rating of the parameters used for this application can be seen in Table III.It gives us information about the most important parameters to be compared among the alternatives.This information was obtained from expert in the medical imaging field.Furthermore, we used Yager index one more time in order to count the weight of the parameters.Lastly, we applied to the visual PROMETHEE program and used Gaussian preference function for the selected criteria (see Table IV).The best alternatives are expected to be of lower cost, have minimum radiation dose and scan time.They are also expected to have maximum specificity and sensitivity for the performance of the devices.

IV. RESULTS AND DISCUSSION
Table V shows the complete ranking of the X-ray based medical imaging devices when they were compared without including the cost of the machine.This is done in order to include parameters that are specific to the patient, being the receiver of the treatment.The total raking shows us that X-ray and mammography which gives less dose of radiation have relatively the same ranking.They are followed by fluoroscopy which all has a positive Net Flow.On the other hand, Computed Tomography and Angiography both having negative Net Flow came second to the last and last respectively on the total ranking table.It can be seen that this is due to the high dose of radiation they give to the patient.Table VI shows the complete ranking of the devices with cost of device activated.As it can be seen, there is no difference from the ranking while the cost was de-activated.But a slight change is noticed in the Net flow of Mammography and Conventional X-ray device.The idea to include the cost in Table VI was to produce a ranking table which will be useful for the hospital management, because price of device largely affects their selection process.The advantages and disadvantages according to the parameters of the devices are given in Fig. 1.These results also give very important information about the properties of the devices should incase the manufacturer needs to make any improvement for the specific property.This was obtained from the Decision Lab visual PROMETHEE program.The program gives the user the ability to manipulate the parameters and make further comparisons according to the decision maker preferences.www.ijacsa.thesai.orgV. CONCLUSION Utilizing multi-criteria decision methods like fuzzy PROMETHEE gives the possibility to accomplish great outcomes by incorporating fuzzy data.This method was applied on various X-ray based medical imaging devices and a useful result was obtained as shown in Section 4. The method has been tested and validated in previous studies, and it provides useful information when used in the present study.It is good and provides alternative solutions to decision maker.The concerned parties can rely on the outcome of this study to make the necessary decision in due course.The study can be improved by adding more criteria to the alternatives.Furthermore, compared to other decision-making methods, the PROMETHEE method has proven to be efficient in many fields.The patients and the hospital management are the beneficiary of the outcomes of this study.This method can be applied to other decision-making problems that exist in medical imaging or other field of study.

TABLE III .
LINGUISTIC SCALE FOR IMPORTANCE

TABLE IV .
VISUAL PROMETHEE APPLICATION

TABLE V .
COMPLETE RANKING OF THE IMAGING DEVICES WITH COST OF DEVICE DE-ACTIVATED

TABLE VI .
COMPLETE RANKING OF THE IMAGING DEVICES WITH COST OF DEVICE ACTIVATED