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Precision medical measurement tools. Discover the Volume Doubling Ruler for fast, accurate assessment of object response on medical imaging.
Volume Doubling Ruler with Cursor Slider.
The Volume Doubling Ruler (also known as the Volume and Area Doubling Ruler) is a specialized medical measurement tool invented by Dr. Colin Paul Spears, a hematologist-oncologist and founder of Fibonacci Phyllotaxis Inc. (dba Fibons)
Measurement of Object Response
Used to measure the size of spherical or near-spherical objects on medical imaging (like X-rays or CT scans) and determine their doubling time.
Interconvertible Scales
Features scales that allow a user to quickly convert a linear diameter measurement into volume or surface area doublings.
Mathematical Foundation
These mathematical models describe asymmetric binary division—a pattern found in both plant growth (phyllotaxis) and certain biological cell populations.
Product Design
Patent for a Transparent tumor size measuring ruler which allows for direct overlay on medical films or digital screens to provide immediate assessment of treatment efficacy.
The VDR is Based on the importance of Tumor (Volume) Doubling Time in Response Criteria.
Partial Response is a 50% decrease in the SPD (Δn A = -1) or 1.5 Volume Doublings decrease (Δn = -1.5), universally agreed upon by WHO, Lugano (Cheson) and RECIST Criteria.
Understanding the Fibons Doubling Ruler
The Volume Doubling Ruler is an innovative and unique instrument for conversion of diameter(radius) information into volumetric and area cm units and Doubling Numbers.
For comparison of similarly shaped objects or tumor measurements over time. Invented by Dr. Colin Paul Spears, a prominent oncologist-hematologist and scientist, the VDR enables clinicians to rapidly calculate tumor doubling times, response velocities, and compare response criteria for determining when progression occurs or response reaches the criteria end-point.
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Volume Doubling Ruler – Tumor Doubling Time Slide Rule Measurement
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Latest News
The Ultimate Guide to Tumor Size Measurement and the Fibons Volume Doubling Ruler
In the rapidly advancing field of oncology, precision is not merely a goal—it is a foundational requirement. Every diagnosis, treatment plan, and …
Who is Dr. Colin P. Spears?
Dr. Colin Paul Spears, M.D. is a prominent, board-certified hematologist-oncologist and research physician based in Sacramento, California. Over a …
Volume Doubling Ruler vs Area Doubling Ruler
Volume Doubling Ruler vs Area Doubling Ruler: Which One Do You Actually Need? The core distinction is this: the Area Doubling Ruler is built …
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