DICOM to PDF

The first medical images are taken at the start of the 20th century, after the discovery of the x-rays in 1895 by the German Professor, and the future first Nobel Prize laureate in Physics, Wilhelm Conrad Röntgen .
The concept of an x-ray is based on the principle of passing radiation through the body and having the images projected on a photosensitive plate placed behind it. Radiology started rather slowly, but it gained a growing interest during World War II and its traumatic injuries.
If Leonardo Da Vinci discovered the sonar principles, it’s the military who used it to detect enemy ships during the two World Wars. We had to wait for the 1960s to see the high-frequency sound wave technology in the medical domain (ultrasounds).
Computed Tomography (CT scan) and the technology of Magnetic Resonance Imaging (MRI) were developed in the 1970s.
In the 1980s, the multiplication of imaging technologies made it difficult to decode the images generated by each device. Also, medical images contain a lot of information related to the patient, which must be analyzed, shared, and stored.
DICOM emerged from the need to have a unified format to work with all types of medical images in 1985. It’s again the Army that made DICOM famous when it needed to replace fragile film-based images by digital images for teleradiology in war zones.

Medical image analysis is used in many different fields of medicine, including clinical study, diagnosis support, treatment planning, and computer-assisted surgery. When we talk about medical imaging , various technologies are involved.
We’ve already mentioned X-rays, a widespread procedure using radiation to get images of the denser parts of the body. Ultrasound (or sonogram) is also very frequent and uses high-frequency waves to show internal organs, muscles, and tendons. A Magnetic Resonance Imaging (MRI) scan is a detailed cross-sectional image of a body part involving magnetic fields and radio waves. A computerized tomography scan (CT scan), creates a detailed image of the inside of the body using x-rays and computers.
Nuclear medicine includes the SPECT (or scintigraphy/gamma scan) and the PET scans. They create 3D images of the inside of the body, thanks to the injection of radioactive tracers to assess bodily functions. The main
difference between SPECT (Single Photon Emission Computed Tomography) and PET (Positron Emission Tomography) scans is the type of radiotracers used. The SPECT scan detects the gamma-ray emissions from the tracers while the PET scan detects the photons produced by the positrons emitted by the radiotracer.

DICOM (Digital Imaging and COMmunications) is the format to store, exchange, and transmit medical images.
It was developed by the American College of Radiology (ACR) and the National Electrical Manufacturers Association (NEMA). It is now the registered trademark of NEMA and an ISO standard .
DICOM includes protocols for image exchange, image compression, 3-D visualization, image presentation, and results reporting.
Its purpose was to replace X-rays films as well as access, share, and archive high-resolution images generated by all types of medical imaging devices. The DICOM standard encodes the image and metadata, which includes confidential information related to the patient. To ensure the security and privacy of the data, the format defines different encryption mechanisms. Medical images are usually very heavy and often need to be compressed to ease sharing and storage. DICOM uses the JPEG 2000 compression. As JPEG2000 can provide lossy or lossless compression, it is up to the specialists to define the context where the usage of lossy compression of medical images is clinically acceptable .