730
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TECHNICAL NOTES
An "Air-Cart" for Scintillation Camera Positioning 1
September 1975
•
George R. Jones, William L. Ashburn, M.D., and Heinrich R. Schelbert, M.D. An air-cart that operates on the laminar air flow principle was designed to permit easy movement of a scintillation camera detector by one operator. Air flow Is obtained from the hospital main supply which Is available In each room. INDEX 'TERM:
Radlonucllde Imaging, apparatus and equipment
Radiology 116:l30, September 1975
•
•
Use of the Anger-type scintillation camera is becoming more prevalent in intensive coronary care units. The studies performed on these patients require careful positioning of the detector and movement between several rooms. Angular and oblique positioning of the detector head is assisted by motor drives, but the weight of the detector and support makes movement within the room difficult. In addition to the physical effort needed to move a typical 1800-lb. (817 kg) detector,2 the ensuing commotion created by several persons pushing the unit toward the patient's bed often disturbs the critically ill individual. The air-cart to be described in this report alleviates these difficulties by enabling one person to move and position with comparative ease the large and cumbersome detector. The air-cart operates on the laminar air flow principle. The laminar air flow creates an essentially frictionless bearing between the cart and the floor with no horizontal directional limitation. The force required to initiate motion of the detector in any horizontal direction is less than ten pounds (4.5 kg). The air flow is created by air from the hospital main supply (60 psi) through four TASC (Transocean Air Systems Corporation)3 Model 17 air bearings mounted on a modified pallet (Fig. 1). The modification of a standard pallet was dictated by the width of hospital doors and the dimensions of the scintillation camera detector base assembly. The detector stand was raised and the pallet slipped under the detector stand leveling jacks. The four jacks were used only for weight distribution adjustment and not for lifting the detector. The maximum load on each of the four bearings must be limited to 40 % of the total weight to ensure proper operation. The height of the pallet is 3% inches (8.3 cm) when not in use and increases to 3% inches (9.2 cm) when in operation. Since the pallet is positioned between the wheels of the detector stand, the net increase in height of the system as com-
Fig. 1. Four "air bearings" are mounted on the pallet as viewed from underneath. When not in motion, the weight is distributed on the round posts in the center of each "bearing." Air flow is through the four small holes surrounding the posts.
Fig. 2.
Operator manipulates in-line control valve while positioning the scintillation camera detector with one hand.
pared with the standard detector configuration is only 1% inches (3.5 cm). The air from the hospital main supply is delivered through a hose to the pallet. A throttling valve is provided at the air main connection. A second valve is located in the hose near the air pallet and permits detector positioning to be controlled by one person (Fig. 2). The air-cart performs very satisfactorily in our hospital Intensive Coronary Care Unit. The primary advantages of the air-cart are the ease of operation by one person, the freedom from wheel restriction, protection of the electronics from sudden jolts, and reducing the probability of personnel injury. One limitation of the present air-cart is that the system requires an air supply and hose, thus restricting its use to certain areas of the hospital. This limitation can be overcome by the use of bottled (compressed) air for short moves or a portable compressor with rechargeable batteries. In addition, the present design of the air-cart limits the ability to move over thresholds such as pile carpeting or elevator interfaces. Even so, plastic sheeting can be placed over these areas to maintain a smooth surface. The air-cart has proved to be reliable, safe, and efficient in our hospital. The noise level from the unit while in operation is surprisingly low and unobjectionable. Complete freedom of motion and ease of detector positioning at the bedside and between rooms justify the use of the air-cart. 1 From the Division of Nuclear Medicine, Department of Radiology, University of California, San Diego Medical Center, San Diego, Calif. 92103. Accepted for publication in April 1975. Supported in part by Myocardial Infarction Research Unit Contract PH-43-NHLI-68-332 and NHLI Grant H2-14197. dk 2 Searle Radiographics Pho-Gamma HP scintillation camera. 3 P.O. Box 30363, Santa Barbara, Calif. 93105.
•
TECHNICAL NOTES
An "Air-Cart" for Scintillation Camera Positioning 1
September 1975
•
George R. Jones, William L. Ashburn, M.D., and Heinrich R. Schelbert, M.D. An air-cart that operates on the laminar air flow principle was designed to permit easy movement of a scintillation camera detector by one operator. Air flow Is obtained from the hospital main supply which Is available In each room. INDEX 'TERM:
Radlonucllde Imaging, apparatus and equipment
Radiology 116:l30, September 1975
•
•
Use of the Anger-type scintillation camera is becoming more prevalent in intensive coronary care units. The studies performed on these patients require careful positioning of the detector and movement between several rooms. Angular and oblique positioning of the detector head is assisted by motor drives, but the weight of the detector and support makes movement within the room difficult. In addition to the physical effort needed to move a typical 1800-lb. (817 kg) detector,2 the ensuing commotion created by several persons pushing the unit toward the patient's bed often disturbs the critically ill individual. The air-cart to be described in this report alleviates these difficulties by enabling one person to move and position with comparative ease the large and cumbersome detector. The air-cart operates on the laminar air flow principle. The laminar air flow creates an essentially frictionless bearing between the cart and the floor with no horizontal directional limitation. The force required to initiate motion of the detector in any horizontal direction is less than ten pounds (4.5 kg). The air flow is created by air from the hospital main supply (60 psi) through four TASC (Transocean Air Systems Corporation)3 Model 17 air bearings mounted on a modified pallet (Fig. 1). The modification of a standard pallet was dictated by the width of hospital doors and the dimensions of the scintillation camera detector base assembly. The detector stand was raised and the pallet slipped under the detector stand leveling jacks. The four jacks were used only for weight distribution adjustment and not for lifting the detector. The maximum load on each of the four bearings must be limited to 40 % of the total weight to ensure proper operation. The height of the pallet is 3% inches (8.3 cm) when not in use and increases to 3% inches (9.2 cm) when in operation. Since the pallet is positioned between the wheels of the detector stand, the net increase in height of the system as com-
Fig. 1. Four "air bearings" are mounted on the pallet as viewed from underneath. When not in motion, the weight is distributed on the round posts in the center of each "bearing." Air flow is through the four small holes surrounding the posts.
Fig. 2.
Operator manipulates in-line control valve while positioning the scintillation camera detector with one hand.
pared with the standard detector configuration is only 1% inches (3.5 cm). The air from the hospital main supply is delivered through a hose to the pallet. A throttling valve is provided at the air main connection. A second valve is located in the hose near the air pallet and permits detector positioning to be controlled by one person (Fig. 2). The air-cart performs very satisfactorily in our hospital Intensive Coronary Care Unit. The primary advantages of the air-cart are the ease of operation by one person, the freedom from wheel restriction, protection of the electronics from sudden jolts, and reducing the probability of personnel injury. One limitation of the present air-cart is that the system requires an air supply and hose, thus restricting its use to certain areas of the hospital. This limitation can be overcome by the use of bottled (compressed) air for short moves or a portable compressor with rechargeable batteries. In addition, the present design of the air-cart limits the ability to move over thresholds such as pile carpeting or elevator interfaces. Even so, plastic sheeting can be placed over these areas to maintain a smooth surface. The air-cart has proved to be reliable, safe, and efficient in our hospital. The noise level from the unit while in operation is surprisingly low and unobjectionable. Complete freedom of motion and ease of detector positioning at the bedside and between rooms justify the use of the air-cart. 1 From the Division of Nuclear Medicine, Department of Radiology, University of California, San Diego Medical Center, San Diego, Calif. 92103. Accepted for publication in April 1975. Supported in part by Myocardial Infarction Research Unit Contract PH-43-NHLI-68-332 and NHLI Grant H2-14197. dk 2 Searle Radiographics Pho-Gamma HP scintillation camera. 3 P.O. Box 30363, Santa Barbara, Calif. 93105.
