ch 8

Digital Imaging Study Notes
Lesson Overview

  • Key Objectives:

    • We will learn the important words used in digital imaging.

    • We will understand why and how digital imaging is used.

    • We will cover the basic ideas behind digital imaging.

    • We will talk about how much radiation is involved in digital imaging.

    • We will identify and explain the tools used for digital imaging.

    • We will learn about the two main kinds of digital imaging and what they involve.

    • We will discuss how to get both the patient and the equipment ready for digital imaging.

    • We will explore the good points and bad points of using digital imaging.

Introduction

  • Purpose:

    • This lesson will teach you the main ideas of how digital imaging works.

    • You will learn about the different kinds of digital imaging systems.

    • We will talk about the benefits and drawbacks of using digital imaging.

Basic Concepts

  • Digital imaging is a modern way to take pictures of teeth.

  • Key aspects include:

    • You don't need traditional film or special chemicals to develop the images.

    • It uses a special electronic sensor and a computer program to create the images.

    • X-ray images appear on a computer screen almost immediately after they are taken.

Terminology

  • Common Terms:

    • Analog image: This is a continuous picture, like a traditional photograph, not made of separate pieces.

    • Bit-depth image: This number tells us how many different shades of color or gray a single dot (pixel) in an image can show.

    • Charge-coupled device (CCD): This is a common type of sensor technology used to capture images, often found in cameras and digital imaging systems.

    • Digital imaging: This is the process of taking pictures using electronic technology instead of traditional film.

    • Digital image: This is a picture stored in a computer-friendly format that a computer can easily process and display.

    • Digital subtraction: This is a special technique used to make specific details in an image stand out more clearly, often by comparing two images.

    • Digitize: This means to change an older-style signal (analog) into a newer, computer-friendly signal (digital).

    • Direct digital imaging: This method captures an image directly onto a computer without any in-between steps like scanning film.

    • Indirect digital imaging: This method involves taking traditional film images and then scanning them to turn them into digital images the computer can use.

    • Line pairs/millimeter (lp/mm): This measurement tells us how sharp and clear an image is; a higher number means a sharper image.

    • Pixel: This is the smallest single dot or square that makes up a digital image on a screen.

    • Sensor: This is the device that "sees" and captures the image, similar to how film captures an image in older systems.

    • Storage phosphor imaging: This is a digital imaging method that uses special plates coated with phosphors that store the image information before it's scanned by a laser.

Purpose and Use

  • Digital imaging is primarily used to:

    • It creates pictures that help dentists find and check for dental problems.

    • It helps dentists spot issues like cavities, other diseases, or problems with teeth and the bones around them.

    • It helps confirm if a patient has a certain disease or identify what kind of disease it is.

    • It helps pinpoint the exact location of problems or any objects that shouldn't be there.

    • It gives useful information to the dentist while they are performing treatments.

    • It helps monitor how teeth and jaws are growing and developing.

    • It shows how teeth change because of cavities, gum disease, or injuries.

    • It creates records of a patient's dental health at different times, which can be useful for tracking progress.

    • It helps dentists create the best treatment plans for their patients.

Fundamentals

  • Definition: Digital imaging is a way of taking pictures using a sensor, breaking these pictures into tiny electronic pieces, and then storing and showing them on a computer.

  • A small electronic sensor is put into the patient's mouth. This sensor then creates an electronic signal which is turned into digital information.

Radiation Exposure

  • Benefits:

    • Patients are exposed to much less X-ray radiation when digital imaging is used compared to old-fashioned film X-rays.

    • Digital sensors are usually so sensitive that they need 5050 to 9090 less radiation than regular X-ray film to create an image.

Equipment

  • Essential Components:

    • X-ray Unit: Most digital imaging systems use a standard dental X-ray machine to produce the X-rays.

    • The timer on the X-ray machine needs to be set for very short exposures, typically about 1/1001/100 of a second, because the digital sensors are so sensitive.

    • Sensor: This is the device placed inside the patient's mouth that captures the dental image.

    • Types:

      • Wired: These sensors are physically connected to a computer using a fiber optic cable.

      • Wireless: These sensors are not connected by a cable to the computer, allowing for more freedom of movement.

    • Charge-Coupled Device (CCD): This is a very common type of image receptor which contains a silicon chip with tiny electronic circuits to capture light and turn it into an image.

    • Complementary Metal Oxide Semiconductor/Active Pixel Sensor (CMOS/APS): This type of sensor is generally cheaper to make and is often stronger or more durable than CCD sensors.

    • Computer: This machine stores the electronic information from the sensor and quickly turns it into a picture (usually in shades of gray) that can be seen on the screen within 0.50.5 to 120120 seconds; it also has features like splitting the screen or making parts of the image larger.

Types of Digital Imaging

  • Direct Digital Imaging:

    • Components: This system includes a dental X-ray machine used inside the mouth, a sensor, and a computer with special software for images.

    • Procedure: The sensor is carefully placed into the patient's mouth. It captures the images and immediately sends them to the computer where they can be improved and saved.

  • Indirect Digital Imaging:

    • Components: This system typically uses a CCD camera along with a computer.

    • Procedure: Existing X-ray films are converted into digital images by using a CCD camera to scan them. Once scanned, these images can then be viewed on a computer monitor.

  • Storage Phosphor Imaging:

    • This is a wireless digital imaging system that uses special reusable plates coated with phosphors instead of wired sensors.

    • Phosphor plates are thin and can fit inside the patient's mouth. After exposure, these plates are scanned by a laser to create electronic files. This method is generally slower than direct digital imaging.

Step-by-Step Procedures

  • Key Steps for Intraoral Sensor:

    • This involves getting the sensor ready and putting it correctly into the patient's mouth.

    • Always follow the instructions provided by the sensor's maker on how to use it, prepare it, and how much X-ray exposure to use.

Intraoral Sensor Preparation

  • Every sensor is made to be waterproof and must be put inside a disposable protective cover to stop germs from spreading.

  • To add extra protection against germs spreading between patients, a small rubber cover (like a finger condom) can be placed under the main protective barrier.

Intraoral Sensor Placement

  • The sensor is held in the mouth using special attachments that the patient bites on or other positioning tools.

  • Technique: The paralleling technique is the best way to take X-rays with digital sensors because it produces very accurate images.

Advantages of Digital Imaging

  • The images show a much wider and finer range of gray shades, which helps in seeing details clearly.

  • Patients receive less X-ray radiation.

  • Images can be seen almost instantly on the computer screen.

  • Once the initial setup is done, there are no ongoing costs for film or chemicals.

  • The process of taking and viewing images is much faster and smoother.

  • The quality of the images is often better, making it easier for dentists to diagnose problems.

  • Dentists can easily show patients their X-rays on screen and explain what they see.

  • It's better for the environment because it doesn't use chemicals or produce hazardous waste like traditional film developing.

Disadvantages of Digital Imaging

  • The first cost to buy all the digital equipment can be quite expensive.

  • Sometimes, the image quality might not be perfect, which could make it slightly harder to diagnose certain conditions.

  • The sensors can be a bit thick and rigid, making them uncomfortable for some patients, especially those with small mouths.

  • It requires careful attention to cleaning and covering the sensors to prevent the spread of infections.

  • Digital equipment can wear out over time, and if a sensor breaks, it can be costly to replace.

  • There are important rules about making sure digital images are not changed or accessed without permission, and they need to be stored securely.

Conclusion

  • Digital imaging marks a big change in how dental X-rays are taken. It offers many improvements but also requires dentists to think about the cost, the quality of the equipment, and how they perform the procedures.