IAEA in Basic Safety Standards (1994) presented Guidance levels of dose for typical Diagnostic radiology. Then, IAEA advises us against being over this level. Again, ICRP in ICRP Publication 60published setting “dose constraint” as upper bounds of individual exposure.
However, many medical treatment facilities don't have a dosimet er in order to measure patient dose.
Then, we measured X-ray output of many X-ray equipments. We statistically analyzed many data measured and could make an approximate equation in order to estimate X-ray output (air ab sorbed dose) of X-ray equipments.
The X-ray output is directly proportional to V^2.232, where V is the tube voltage. The coefficient of determination showed a high value.
By revising this approximate eq uation with various revision coefficients, we made an estimated equation could estimate patient dose in Diagnostic radiology. We think that this estimated equation of patient dose can easily employ any medical treatment facilities.

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It is very important which the special xray equipment and photosensitive materials merely are prepared but also their maximum ability are shown for mammography which is taken photography of breast tissue having a few absorbed difference and requires showing the detail of change to a morbid state.
Especia lly, the physical properties of film are influenced on developing conditions, namely, developing temperature, developing time and developer. In this study, the physical properties were investigated by using some developing conditions.
In the results, it has been confirmed, which the temperature dependencies on physical properties of films for mammography are different with developing time and developer.
Furthermore, it has been confirmed, which it is very important wh en the maximum ability of the films for mammography is required, the suitable developing temperature must be investigated by using the automatic processor of each institution, that is, by using the developing time and developer of each institution.

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Recently many attentions have been paid on DICOM which is a standard of medical image communication. Communications between imaging apparatuses provided by different vendors have been made possible by DICOM and have become easy.
In this study we connected medical image acquisition apparatuses and image processing systems to a DICOM file server system. The characteristics of image- transfer between these systems were studied. These systems were connected to each other via TCP/IP on FDDI or Ethernet. Images acquired with the apparatuses (MRI, DR, FCR, and Film digitizer) were possible to be transferred to the DICOM file server and stored herein. Image files in the DICOM file server were possible to be retrieved and fetched with the image viewers (FAINWORKS, POP Net, VOX- BASE, and Dr. View) and then displayed hereon.
The linear model was as sumed for the relation between the time required for image transfer and the file size, to study the characteristics of image transfer. The times were measured with varying different file size for the communications between image acquisition apparatus and the DICOM server and between the viewers and DICOM server. From these measurements the characteristics of the system were clarified.
It was found that the time required for whole transfer process could be divided into two parts, namely, the time for preparation and the transfer time during which data were on the transfer line. The latter depends on network protocol. The transfer time for FDDI was about 1/10 of that for Ethernet. In dealing with the large imaging files such as DR or CR, waiting time can be alleviated by using the high speed network protocol like FDDI or 100BASE-TX.

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The scatter factor (SF) formalism which Bjarngard has developed is so constructed that it can be applied to any high-energy photon beam, containing the in-water attenuation coefficient as a variable. However, it has not been confirmed that the SF formalism can reasonably be applied to small depths where longitudinal electron equilibrium does not exist and to small fields where lateral electron equilibrium does not exist. A method has been proposed to obtain reasonable SF data at such small depths and fields using the characteristics of a scatter dose-spread kernel. A 10-MV x-ray scatter dose-spread kernel is given which is produced based on the SF formalism.

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