YY/T 0310-2015General specifications for X-ray equipment for computed tomography (English PDF)

4.1 Classification

Security classification shall comply with the requirements on classification in GB 9706.1.

4.2 Composition

CT scanner shall be composed of the following parts.

a) Scanning frame;

b) X-ray generator;

c) Patient support;

d) Console;

M1, M2 - Marks on patient support surface; d1, d2 - Distance between marking point and Z-axis.

5.7.2 Patient support surface

Patient support surface shall be plane, or the attachment which can make it as plane shall be indicated in accompanying file and make it obtained.

Positioning aids of therapy system are allowed to use by patient support.

5.7.3 Diagnostic bed sag (patient support rigidity)

It shall stipulate the diagnostic bed sag within 40 cm (typical scan length plus the amount of movement of scanning plane).

5.7.4 Integrated positioning light used for patient positioning

If positioning light is integrated in CT scanner, accompanying file shall verify if the intended use of positioning light can be used for patient positioning in RTP.

If the intended use of positioning light can be used for patient positioning in RTP, it shall have the following accuracy.

The accuracy of axial positioning light at isocenter shall be ± 1 mm. The accuracy at ± 250 mm in X direction shall be ± 2 mm.

Sagittal and coronal positioning lights shall be extended to within scanning plane. The accuracy related to rotation axis shall be ± 1 mm.

Marking line width of positioning light at isocenter (FWHM) shall not exceed 1 mm.

5.7.5 Typical scanning mode that generates RTP

The accompanying file shall stipulate the typical CT operating conditions which generate images for RTP. The agreement not applicable to generate RTP image shall be indicated in the accompanying file.

For RTP's typical CT operating conditions, the accompanying file shall provide measurement results of noise, average CT value and uniformity measured by the methods in GB/T 19042.5-2006.

5.7.6 HU value conversion

HU value of each model measured under CT operating conditions indicated in 5.7.5, and the conversion of electronic and mass density values related to

a) CT scanner appearance shall look neat, beautiful; the surface shall be smooth and clean; the color shall be even; there must no damage spots, cracks and other defects;

b) The main electroplating pieces of CT scanner shall comply with requirements on grade 2 appearance in YY 0076-1992.

5.9 Environment test

It shall comply with requirements of YY/T 0291. The final test items shall at least contain 5.2.1, 5.2.2, 5.2.3, 5.2.5, 5.2.8 and 5.5.3.

5.10 Safety

It shall comply with requirements of GB 9706.1, GB 9706.11, GB 9706.12, GB 9706.14, GB 9706.15, GB 9706.18, YY 0505 and YY/T 0708.

6.1 Test conditions

CT scanner shall be tested under the following conditions.

a) Unless otherwise specified, all performance tests shall be conducted under conditions stipulated in 5.1;

b) CT body model which complies with American Association of Physicists in Medicine (AAPM) standard is recommended;

c) Unless otherwise specified, it shall use CT conditions of typical head and body to scan.

6.2 Performance

6.2.1 Image noise

Under typical head scanning conditions (recommended to use 10 mm slice thickness), use head CTDI body model to measure center dose.

If the equipment does not have 10 mm slice thickness, the product standard shall stipulate the conversion factor of image noise.

Place the homogeneous medium body model (20 cm water model) within scan field of view. Make body model axis coincide with the rotation axis of scanning frame. After scanning, select a region of interest of which the diameter is about 40% of image diameter. Measure the standard deviation SD of CT value in this region. Use formula (1) to calculate noise value N. reconstruct. Adjust the window width and window level. Observe the image through monitor. Take the diameter of the distinguishable minimum hole group as reference.

6.2.6 Operating noise

In the fastest scan state, use sound level meter to respectively measure the operating noise at 1.5 m height from ground, 1 m from the front, back, left and right of scanning frame surface. Take the maximum.

6.2.7 Artifact

Place water model within scan field of view. Make body model axis coincide with the rotation axis of scanning frame. Select a group of CT operating conditions to scan. Observe water model's CT image when window level is 0, window width are respectively 50 HU, 100 HU.

6.2.8 Slice thickness

This Standard recommends the following method. […]