Mammogram Equipment PDF

Ch(6) Mammogram equipment Introduction  Mammgraphy is a radiographic modality to detect breast pathology and cancer.  Breast cancer accounts for 32% of cancer incidence and 18% of cancer deaths in women in the United States.  Approximately 1 in 8 or 9 women in the US will develop b...

Ch(6) Mammogram equipment Introduction  Mammgraphy is a radiographic modality to detect breast pathology and cancer.  Breast cancer accounts for 32% of cancer incidence and 18% of cancer deaths in women in the United States.  Approximately 1 in 8 or 9 women in the US will develop breast cancer over her lifetime. Mammography is a specific type of imaging that uses a low-dose x-ray system for examination of the breasts. Common uses of the procedure: Diagnostic mammography is used to evaluate a patient with abnormal clinical findings , such as a breast lump or lumps that have been found by the woman or her doctor. Mammography equipment:  A mammography unit is a rectangular box that houses the tube in which x-rays are produced.  The unit is dedicated equipment because it is used exclusively for x-ray exam of the breast , with special accessories that allow only the breast to be exposed to the x- rays.  Attached to the unit is a device that holds and compresses the breast and positions it so images can be obtained at different angles. Breast compression is necessary in order to:  Press out the breast thickness so that all of the tissue can be visualized;  Spread out the tissue so that small abnormalities won't be obscured by overlying breast tissue;  Allow the use of a lower x-ray dose since a thinner amount of breast tissue is being imaged;  Hold the breast still in order to eliminate blurring of the image caused by motion;  Reduce x-ray scatter to increase sharpness of picture. Preparation for a mammogram:  Remove deodorant , talcum powder , or lotion under the arms or on breasts on the day of the exam. (These can appear on the x- ray film as calcium spots.)  Patient must describe any breast symptoms or problems to the technologist performing the exam.  Previous mammograms must available to the radiologist at the time of the current exam.  In addition , before the examination , the patient asked to remove all jewelry and clothing above the waist and will be given a gown that opens in the front. Machine components X-ray tube X-ray generator Compression device, spot Control panel, protective screen Cassette bucky, grid Machine components  Molybdenum target and Molybdenum filter  Thin glass window  Closer electrode space  Small focal spot size 0.3-0.6  24-35 Kvp 80-100 mA 1-4 seconds  Automatic timer (ionization chamber) behind the film  3 phase generator  Single emulsion film single screen  Stationary or moving grid Compression device  Radiolucent device for: ✓ Reducing patient dose ✓ Improving image contrast ✓ Reducing exposure time (motion blur) ✓ Spread breast tissue ✓ Spot device→ Compression ❖ Compression is achieved with a low attenuating lexan paddle attached to a compression device ❖ 10 to 20 Newtons (22 to 44 pounds) of force is typically used ❖ A flat, 90°paddle (not curved) provides a uniform density image ❖ Parallel to the breast support table ❖ Spot compression uses small paddles ❖ Principal drawback of compression is patient discomfort Radiation dose  Mammogram routinely done after 35 years  Patient dose for the main view is 1.8-3.5 mGy (1Gy = 1 rad)  Breast US can easily differentiate between cyst and solid lesion ❖Main screening views (2) ❖Additional views (4) Mammographic stands Complete mammographic unit  Breast support/film –holder  Breast compression  Tube support  Full range of movement Breast cones  Modern Equipment ❖ Dedicated Mammography Equipment ❖ Specialized X-ray Tubes ❖ Optimized Screen/Film detector systems ❖ Breast Compression Devices stereotactic  CH(7) Dental x-ray equipments Intra oral equipments  Dental X-ray Equipment Dental radiography is one of the most common x-ray examinations in the industrialized world. Although individual radiation doses and risks are low, many extensive examinations are performed in younger age groups. As for other radiological procedures, patient doses can be significantly influenced by the equipment and techniques used and the quality assurance measures in place. 21  Dental X-ray Equipment (cont) Different types of equipment are used depending on the type of image required. e.g. x-ray equipment for intra-oral radiography uses small intra- oral non-screen x-ray films for bitewing or periapical radiography; equipment for panoramic tomographic radiography uses a narrow fan shaped x-ray beam (~5-10 mm waide and 150 mm high) which rotates around different axes within the patient’s head to provide a defined image of the plane of the dental arch. Other unwanted structures are deliberately blurred during this process. 22 Dental X-ray Equipment (cont) Intraoral x-ray examination FILM HOLDER AND POSITIONING DEVICE 23 Specific Requirements for Intraoral Equipment The operating tube voltage should be at least 60 kV peak. The filtration in the useful beam should be equivalent to at least 1.5 mm Al at x-ray tube voltages up to 70 kV peak and 2.5 mm if greater than 70 kV peak. X-ray tube focus to skin distances of 200 mm or greater are recommended. The diameter of the x-ray beam should not be greater than 60 mm at the outer end of the beam applicator. Rectangular collimation is recommended. 24 Specific Requirements for Intraoral Equipment (cont) The fastest films consistent with the required clinical results should be used. Whenever practicable, film holders incorporating beam aiming devices should be used. On new equipment, manufacturers should provide a range of x-ray outputs and exposure times so that different speed image receptors (faster film and digital image receptors) can be correctly exposed. 25 Dental X-ray Equipment (cont) Older “pointer cone” equipment. Open ended collimation (right) should be used 26  Specific Requirements for Panoramic Equipment The rotation of the x-ray tube around the head that provides the tomographic image of the entire dental arch must be precise and reproducible. Patient positioning devices should be simple, reliable and accurate. A fast intensifying screen / film combination (or comparable speed image receptors) should be used. All new equipment should incorporate a range of radiographic exposures consistent with clinical requirements, the patient’s build (i.e. adults, children) and the speed of the image receptor. 27 Dental X-ray Equipment (cont) Panoramic tomographic x-ray equipment 28 Chair-side units  Not occupy much space  Simple easy positioning  Easy angulations  Sufficient x-ray output  Radiation and electrical production  Exposure switch: Hand time switch (long enough) Electronic timer switch Tube head  Oil filled and vacuum sealed  Contain the transformer and the tube  Mounted in a gimbals to move in two planes  No need for locks(finger tip pressure)  Cone in the head top to give skin distance of 18-23 cm  Fixed out put 12 mAs & 55 Kvp  Using of added filter Specialized dental equipment cephelostat (craniostat) cephelostat (craniostat)  Wall-mounted and rigid structure  Permits a precise correlation of position to be established between x-ray tube, head of pt., and the anode of the tube  Examination of teeth, facial bones ,and soft tissue  For orthodontist purpose  supplied with filter and grid  High out put up to 150 mAs & 125 Kvp (suitable for long SID) Orthopantomography OPG pantomography Magnification is due to long OID orthopantomography Tube head convex Cassette-carriage A pair of intensifying screens Patient-support Focal area 0.6*0.6 mm Filtration of 3 mm Al Single 15*30 cm film Bite block Chin support Forehead support Right left temporal supports Right left face-plates A handle on either side of the unit  Single-pulse generator  55-85 Kvp  Fixed 15 mA & 15 sec  Some example are: 8,10,12,15 mAs 40-100 kVp 1-15 sec Portable dental unit: -stationary anode -self rectification -the tube and the transformer are in the head