CCD Image Sensors for Dental Use
Up until now, physicians and dentists have used film to obtain X-ray images. However, digital imaging has advanced to the point where CCD image sensors can now be used to obtain X-ray images in digital form, rather than film.
CCD image sensors offer the following advantages over film:
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Lower patient X-ray exposure (1/5th to 1/10th that of film)
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No developing is needed, so images are displayed extremely quickly.
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The contrast can be adjusted and images can be enlarged, which are helpful when obtaining informed consent from patients.
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The data is in digital format, which facilitates image control (database storage, network support, etc.).
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No developing fluid is needed with digital imaging, so the digital format is advantageous from an environmental standpoint. Additionally, no film is needed.
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Three types of X-ray imaging systems are used in dental hospitals and offices: Intra-Oral(individual teeth), Panoramic(full mouth), and Cephalo(full head). Hamamatsu Photonics provides all of the sensors used in these three types of systems. One feature of Hamamatsu Photonics products is that, because the CCDs, FOPs and scintillators are all manufactured by a single company, they are available in a wide lineup and offer outstanding overall performance.
Image sensors in Hamamatsu Photonics CCD products
Hamamatsu Photonics sensors consist of an FOS (an FOP with a scintillator) coupled to a CCD. The scintillator converts transmission X-rays to visible light, after which the visible light is detected by the CCD. All of the sensors, whether designed for the Intra-Oral, Panoramic, or Cephalo systems, have the same configuration.
1. For the Dental (Intra-Oral) system
This sensor is inserted into the mouth to take images of two or three teeth at a time. Responding to the market demand for high resolution of 20 Lp/mm, Hamamatsu Photonics makes the sensor available in two types, one containing 1.5 million pixels and the other 2.04 million pixels. The pixel size is 20 x 20 μm in both types. (Earlier products were limited to 10 Lp/mm and 240,000 pixels.)
Moreover, each of these products is available in a modular type as well as in a device configuration.
For the modular products, a USB module (C9266-02) is available that makes it possible to collect data using a computer, and we are currently in the process of acquiring CE marking for these products in integrated form.
*For the Intra-Oral system, a low-cost product is also available that uses GOS film instead of FOS (GOS film has a lower image quality than FOS).
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2. For the Panoramic system (S7199-01)
This is the sensor used in the Panoramic X-ray system, in which the patient's head is in the center of the X-ray source and the sensor rotates around the head. Panoramic systems are being used in many dental hospitals and offices. They operate based on a method called Time Delay Integration (TDI) to produce panoramic images much longer than the length of the sensor. This product (S7199-01) has two chips, each 75 mm in length, positioned close to each other to achieve a total length of 150 mm. The seam where the two chips join is corrected by the software so that it doesn't stand out, but because
there is only one seam, it can be corrected more easily than those in other products, which have multiple seams. Our customers like the resulting image quality, reporting that it exceeds that of other products.
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3. For the Cephalo system (S8658-01)
This is used in the Cephalo X-ray system, and as with the Panorama type, images are captured using TDI. The Cephalo system is used by orthodontists.
The S8658-01 uses three of the same chips used in the S7199-01 (approximately 220 mm long). Otherwise, the construction and features are the same as those of the S7199-01.
It is thought that digitalization of X-ray imaging in medical fields will continue to advance rapidly in the future. In anticipation of that progress, Hamamatsu Photonics is continuously striving to reduce the costs and improve the features of our products.
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