• X-Ray

    Effect of photon energy on X-ray images

    I assume that everyone has had at some point the experience where less was more. Especially when dealing with computer based image postproduction. Software makes handy wonderful, or better: powerful, filters. Experienced artists know that only a pinch of something or homeopathy is a key to better results.

    The same holds true in X-ray production. A maximum of energy does not provide better images. Let’s look closer at this point.

    What is the influence of energy to X-ray images ?

    Higher energies in X-rays mean shorter wavelengths and a higher resolution. Therefore it might seem reasonable to increase the energy in our X-ray tubes always to the maximum to produce incredible images based on a maximum resolution.

    With four images below I show the influence of increased energy levels on X-ray images of a single rose. The applied energy levels are 40kV, 60kV, 90kV and 109kV. The steps of postproduction were the same in every image. Slight differences are owed to best contrast in each exposure.

    Surprisingly to the novice we get an increasing loss of contrast (or less available contrast) in each image with higher energies. This effect of loosing contrast can easily be seen in this series of four X-rays and is highest at 109kV.

    Rose digital X-ray photo at 40kV © Julian Köpke
    Rose digital X-ray photo at 90kV © Julian Köpke
    Rose digital X-ray photo at 60kV © Julian Köpke
    Rose digital X-ray photo at 109kV © Julian Köpke

    The explanation for less available contrast with higher energies is the following physical effect: the more photons have shorter wavelengths the more photons run unaffected through the object down onto the sensor. With all photons running through without any hindrance the sensor would show a homogenous gray value.

    Every structure looses contrast when turning to higher energies. The optimum for a structure is found by experience and varies significantly.

    In the medical field the applied energy strongly depends on the purpose of the examination and the structural demands to be diagnosed.

    The above demonstrated meaningless low contrast for our single rose at 109kV doesn’t hold true at all in radiology. Radiologists use frequently 125kV for a chest film to get reproducibly valuable contrast in most patients.

  • X-Ray

    Fusion X-ray of tulips

    Fusion imaging is beauty made of composite X-ray images and HDR images on a light box. The primary question is what energy fits best for flowers. To my experience 40 kV is often suitable. But: the proof of the pudding is in the eating.

    Mammography systems start e.g. from 20 kV and reach 39 kV. The sensor is up to 24cm x 30cm. Conventional systems start from 40 kV and reach 125 kV. The sensor is up to 43cm x 43cm what makes them more attractive to floral compositions.

    The higher resolution and the lower energies of a mammography will suit better for transparent objects. But the spatial limit of a composition (which is 24cm x 30cm) might put hard restrictions on the artist.

    Floral compositions have more creative space with a bigger sensor. But the X-ray tube starts with 40 kV and this might lead to overexposure of tender structures.

    Thus I performed today more than ten compositions to study this relation.

    After four exposure of three tulips I found this composition with four dense blossoms attractive to go further. The composition might somehow resemble to a sketch of three angels. The image is nice due to very soft edges of their „wings“, technically blown out portions in the image.  The inner structure of the nearly closed blossoms is well resolved. The stalks serve as „body“. There is no advantage with higher energies.

    X-ray three tulips © Julian Köpke

    The same composition was done immediately after the X-ray as a bracketing series on a lightbox. After returning I processed a manual HDR, the colors not to warm.

    Three purple tulips HDR photo © Julian Köpke

    The final fusion image is a composite of the preceding two images. Compared to the lightbox photo, the hidden stalks reappear naturally, the inner petals are outlined like a sketch.

    Three purple tulips fusion X-ray photo © Julian Köpke
  • X-Ray

    Radiating Beauty: Creating a new photographic form with fusion X-Ray images

    The shapes and forms are recognizable, yet the level of detail is deeper than the human eye can normally perceive: Leaves appear minutely laced and surfaces are impossibly intricate, somewhere between translucent and opaque. Welcome to the captivating work of photographer Harold Davis and radiologist Dr. Julian Köpke, who combine their skill, passion, and vision to create stunning X-ray photography and pioneering fusion images. Read more on the Pixsy blog (article by Natalie Holmes).

    This nice article was posted today to share the fascination of our common work on fusion X-ray images using a light box manual HDR photo of flowers and their X-ray.

    Fusion image Gloriosa lilly © Julian Köpke

    Our X-ray data are the same, our photographic data a nearly the same: Harold used a Nikon D850 and I used a Nikon D810A, which is modified for astrophotography. Our common lens was a Zeiss Makro-Planar T* 2/50 ZF.2.

    We have some techniques and some principles in common, yet we are different individuals with different results. The next image is partly inspired by Harold’s version. Blue is the complementary color to yellow and fits nicely into the petals. The red color in the center is an image of the sun in monochromatic Hα light using a Fabry-Perot-Interferometer. So this image is a triple fusion image of three different light sources ! If you look closer at 2pm in the center, there are two sunspots.

    This sunflower is a composit of X-ray, monochromatic Hα light of the sun and a sunflower on a lightbox. © Julian Köpke
  • Lightbox,  X-Ray

    X-ray fusion photo of a Nautilus

    Fusion imaging can be done retrospective. My split Nautilus shell on a light box rendered with manual HDR shows already a nice structure of the inner parts. 

    Nautilus shell manual HDR photo on a light box © Julian Köpke

    The X-ray obtained a couple of days earlier easily fits onto the HDR with not a big deal of processing.

    Nautilus X-Ray Energy Compressed © Julian Köpke

    The meaning of the fusion image may be different to the flowers. But it’s feasible to do it retrospectively.

    Nautilus shell fusion X-ray photo and manual HDR photo on a light box. © Julian Köpke
  • General,  X-Ray

    Anyone can have a mishap

    There are many stops put to a CT-scan, especially when dealing with women in reproductive age. We are always very careful before exposing any patient to radiation. 

    This middle-aged patient with repeatedly nausea and discomfort opposing pregnancy very strict and claiming menstruation 28 days ago underwent some medical examinations including gastroscopy and, eventually, a CT-scan.

    We were prepared for a tumor when scanning the abdomen. We were amazed to find a baby despite many questions about patient’s history before the exam. Maybe, some obesity covered the situation with a veil.

    You can see the bones of the upper and lower extremities, as well as the skull and some parts of the spine. The ossification of knees, feet and hands will take place the next ten years after birth.

    Tumor of the lower abdomen causing nausea © Julian Köpke

    It appears to be discussion-worthy if it’s a boy. Our methods didn’t lead us further on this.

    To me the rotated, inverted and cropped image resembles to cave paintings. These paintings are assumed to be some kind of religious art, reflecting astonishment and grandeur of lost civilizations.

    Certain is, the baby touches its right ear, as it was amazed by itself or reflecting its life. What else than human life is this ?

    Tumor of the lower abdomen causing nausea. Rotated image, inverted gray scale and cropped. © Julian Köpke
  • X-Ray

    Tilted Nautilus X-ray photo

    Imagine a Nautilus shell tilted to the surface of the X-ray sensor. The parts close to the sensor are sharp, the distant parts unsharp. Because the X-ray beam creates a central projection. The focal plane is the plane of the sensor, in focus are those parts close to the sensor.

    The shell looks like entering the image or leaving it.

    Tilted Nautilus digital X-ray photo. © Julian Köpke
  • X-Ray

    Nautilus shell X-ray fusion photo of energy levels

    Different energies of X-ray radiation mean different transparency of an object. There is an example in my FAQ using a Nautilus shell.

    Instead of compressing images of different energies to a single image today I subtracted the 70 kV image of a Nautilus shell from the 40 kV image.

    The central parts of the Nautilus shell are more dense and show a significant higher difference. The core of the shell gets shiny. This is how it looks like:

    Energy difference X-ray photo of a Nautilus shell. The image is the difference of a 70kV and a 40 kV image. © Julian Köpke

    In positive X-ray representation you can compare the results. Left hand is the compressed image of 4 different energy levels, right hand the difference image.

    Nautilus X-Ray Energy Compressed © Julian Köpke
    Energy difference X-ray photo of a Nautilus shell. The fusion image is the difference of a 70kV and a 40 kV image in X-ray positive representation. © Julian Köpke
  • General

    Organ music

    I like organ music. And I like the architecture of an organ. It’s always a composition of different metals and woods.

    Today my favorite organ player gave us nice preludes as a present during the service.

    Lantern above the fingerboards © Julian Köpke
    Fingerboards of our organ © Julian Köpke
    Organ pipes © Julian Köpke
  • X-Ray

    Dahlias fusion X-ray HDR photo

    Long time ago my friend Harold and I did these X-rays in my practice. There was so much to do. Today was a chance to process the fusion images. Some details can be found in my FAQs.

    The manual HDR is already appealing to our eyes.

    Dahlias using manual HDR in visible light

    There is some charm in the X-ray image of the same composition. The hidden parts of the stalks can be clearly seen. 

    Five Dahlias X-ray photo © Julian Köpke

    The fusion image of this composition shows both color and hidden structures.

    Dahlias fusion digital X-ray with manual HDR photo in visible light

    Finished image with a background:

    Dahlias fusion digital X-ray and manual HDR photo with background © Julian Köpke
  • X-Ray

    Nautilus shells 3D X-ray photo

    How does an X-ray look like with a complete, unsplit specimen of a Nautilus shell ? Will X-rays go through the object ?

    My three Nautilus shells I bought in Crete are split specimens. The following approach will give an answer to the question. My composition of my shells is 3-dimensional and in nearly upright position. X-rays were then done with different directions of the radiation to study the effect.

    Positioning of the three Nautilus shells on the X-ray sensor © Julian Köpke
    Positioning of the three Nautilus shells on the X-ray sensor © Julian Köpke

    The first image was obtained with radiation coming from the top.  The native X-ray representation is with a black background. Historically this was a film negative. Radiologists speak of „transparent“ areas where a film is black. Consequently, white areas are called „opaque“.

    The result of radiation coming from the top and slightly tilted shells gives different insights of each shell. The composition looks like a complex mathematical surface or some flying insect. 

    Nautilus shell 3D Digital X-ray Photo © Julian Köpke

    The inverted (or „positive“) representation is weightless and our mind starts to produce lots of phantasies about the composition.

    Nautilus shell 3D Digital X-ray Photo inverted © Julian Köpke

    The effect of colorizing an X-ray is not only graphically. It looks more natural.

    Colorized Nautilus shell 3D Digital X-ray Photo © Julian Köpke

    The following image was obtained by combining the inverted image with a flat projection of a single shell to a single image. Now one gets an idea of the effect of the beam path.

    Nautilus shell 3D Digital X-ray Photo © Julian Köpke

    A tilted beam path shows the a bit more detail of the „wings“. Tilt was about 30 degrees.

    Nautilus shell 3D Digital X-ray Photo tilted beam © Julian Köpke
    Nautilus shell 3D Digital X-ray Photo tilted beam © Julian Köpke

    Tilt by 45 degrees shows more of a Nautilus as we know it.

    Nautilus shell 3D Digital X-ray Photo tilted beam © Julian Köpke