IS/IEC 61262 : PART 1 : 1994 : MEDICAL ELECTRICAL EQUIPMENT - CHARACTERISTICS OF ELECTRO-OPTICAL X-RAY IMAGE INTENSIFIERS PART 1 DETERMINATION OF THE ENTRANCE FIELD SIZE

NATIONAL FOREWORD

This Indian Standard (Part 1) which is identical with IEC 61262-1 : 1994 'Medical electrical equipment - Characteristics of electro-optical X-ray image intensifiers - Part 1: Determination of the entrance field size' issued by the International Electrotechnical Commission (IEC) was adopted by Bureau of Indian Standards on the recommendation of Ionizing Radiation Imaging and Radiotherapy Equipment Sectional Committee and approval of the Medical Equipment and Hospital Planning Division Council.

This standard was first published in 1993 as IS 13728 :1993 'Entrance field sizes of electro-optical X-ray image intersifiers' by adopting IEC 520-(1975). IEC 520 (1975) had been withdrawn and replaced by IEC 61262-1 : 1994. This standard will therefore supersede IS 13728 : 1993 and after the publication of this standard IS 13728:1993 shall be treated as withdrawn.

This standard considers both the nominal entrance field size and the useful entrance field size. The nominal entrance field size is calculated from several useful entrance field size measurements. Measurements of the useful entrance field size in the magnification modes of the electro-optical X-ray image intensifier is also considered in this standard.

The entrance field size of electro-optical X-ray image intensifier can be specified in several ways depending on the specified source to entrance plane distance (SED). Typically, the entrance field size is specified as a nominal entrance field size or as a useful entrance field size. The source to entrance plane distance (SED) for the nominal entrance field size is infinite, while the useful entrance field size is measured at a specified SED, usually one metre.

IEC 61262 has been published in various parts. The other parts which have been adopted so far are:

Part 2 Determination of the conversion factor

Part 3 Determination of the luminance distribution and luminance non-uniformity

The text of IEC Standard has been approved as suitable for publication as an Indian Standard without deviations. Certain conventions are, however, not identical to those used in Indian Standards. Attention is particularly drawn to the following:

a) Wherever the words 'International Standard' appear referring to this standard, they should be read as 'Indian Standard'.

b) Comma (,) has been used as a decimal marker in the International Standard while in Indian Standards, the current practice is to use a point (.) as the decimal marker.