Reliable and useful cardiothoracic ratio scale for calculating CTR value made in Japan

CTR value can be calculated directly from chest x-ray photo 

Degree of cardiac hypertrophy can be calculated easily.

Easy for use at  medical front site.

Upper half of slide rule: Scale for measuring LH and LT on chest X-ray photo

LH: heart horizontal transverse diameter  LT: thorax transverse diameter

       from  chest x-ray photo

 Lower half of slide Rule for calculation

Usage

1) With the upper half of the scale, measure the (maximum ) heart horizontal transverse 

    diameter (LH) and the (maximum ) thorax transverse diameter (LT) on chest x-ray

     photo.
2) To move the lower half part of slide ruler to the place of measured value and then   

    cardio-thoracic ratio (CTR  L H÷LT) can be calculated.

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1958 Slide rule competition was held

Hemmi slide rules were used for the designing of Tokyo Tower

Track record of special slide rule's manufacturing and sales
•Business management-related calculation (business diagnostics, profit margins, etc.)
•Pollution-related calculation (diffusion of stack gas, etc.)
•Medical-related calculation

(cardio-thoracic ratio, pulmonary ventilation capability, instillation rate, etc.)
•Health-related calculations (degree of obesity check, calorie calculation, etc.)
•Aircraft-related calculation (load balance, etc.)
•Architectural design-related calculation (architectural structure designs, etc.)
•Calculation for duct piping, fluid design-related calculations (air conditioning design, pipe diameters, etc.)

Strength of Hemmi's Slide Rule

Over 80 years, we have accumulated know-how and proficiency in design and development of slide rules.
Easy to compute approximate values of complex technical calculation, repeated calculation or calculation performed at high frequency. 
If you have an idea for an equation, we will look into the possibility of making a slide rule for it.  

Company Information

 Company Profile

ISO Certificate

2000   Acquired ISO 9001 certification
2005   Acquired ISO 14001 certification

Company History

Operating  Business

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