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Intraoperative 3-Dimensional Radiography of the Kidney. Modified Technique
0022-534 7/84/1325-0872$02.00/0 THE JOURNAL OF UROLOGY
Vol. 132, November
Copyright© 1984 by The Williams & Wilkins Co.
Printed in U.S.A.
Original Articles INTRAOPERATIVE 3-DIMENSIONAL RADIOGRAPHY OF THE KIDNEY. MODIFIED TECHNIQUE J. M. GIL-VERNET AND A. CULLA From the Department of Urology, University of Barcelona School of Medicine, Barcelona, Spain
ABSTRACT
We present a technical modification of 3-dimensional intraoperative radiography of the kidney that reduces the cost of the material and makes preparation of the minichassis in the hospital laboratory possible. The radiogenic dose received by the kidney is 20 times less than when the system is used without screens. Previously, we reported a method of 3-dimensional intraoperative radiography of the kidney that made detection and localization of small calculi and calcifications possible with less
A
bag (fig. 1, B), which is hermetically sealed (fig. 2). The bags may be sterilized with liquids or steam. Once the x -ray has been taken the intensifying screens are recovered and can be
B
FIG. 1. A, components of minichassis. 1, plastic bags. 2, reusable intensifying screens. 3, radiographic film. 4, reusable aluminum antidiffusor. B, minichassis equipment ready for use.
exposure and larger images than those obtained with the conventional chassis. 1 In the Editorial Comment Dr. William Boyce stated his opinion that the cost of the minichassis was excessive, since the screens could not be reused and that the relative decrease in the radiogenic dose received by the kidney with our radiographic system was insignificant compared to that of the conventional chassis. We present the solution to the cost of the material plus a detailed radiogenic calibration compared to conventional radiography.
used again (fig. 3). Therefore, the only costs are for the plastic bag and film, which are minimal.* Another advantage of preparing the chassis in the hospital is that the formation of a veil and black spots on the film is avoided. These defects are produced when the screens and film remain in contact for a long time, which causes radiation to activate the phosphorus of the strengthening screens.
NEW PREPARATION TECHNIQUE
The importance of using strengthening screens lies in the fact that they reduce the exposure time by a factor of 20. This eliminates kinetic blurring (kidney movements) and the kidney receives only 1/20 of the absorbed dose of the systems without screens. Also, the radiogenic dose absorbed by the kidney is reduced by adding another 2 mm. filter to the x-ray tube, which must have a 1 mm. aluminum filter (3 mm. total). This increase in filtration lessens the hardly penetrating soft radiations com-
The minichassis consists of the previously reported elements constructed so that they can be prepared easily in the x-ray laboratory days or even hours before use (fig. 1, A). The different elements are placed inside the corresponding plastic Accepted for publication March 16, 1984. * Available from Rosex, Ciudad Balaguer, 27, Barcelona (22), Spain. 872
RADIOGENIC DOSE
873
FIG. 2. Sealing of both sides of plastic bag with bioactive equipment
pared to the more penetrating harder radiations, which increases the characteristics of the image and also diminishes the absorbed dose (see table). REFERENCE 1. Gil-Vernet, J. M. and Culla, A.: Advances in intraoperative renal
radiography: 3-dimensional radiography of the kidney. J. Urol., 125: 614, 1981.
EDITORIAL COMMENT These authors have the most immediately practical and universal technique for finding stone fragments. Presently, removal of stone fragments is an important part of the treatment of calculous disease. More than ever we seem to accept leaving behind by whathas been documented ever technique is used for removal of calculi. that infection alone or in combination with recurrent cakuli and growth of the fragments are ultimate consumers of renal functional reserve. The mere fact that we have different approaches to the removal of major calculi will not alter these complications. William H. Boyce Department of Surgery Bowman Gray School of Medicine Winston-Salem, North Carolina
FIG.
3. Minichassis placed on plate-holders
Comparison of radiation doses with and without screens
Aluminum filter characteristics (mAmp.): 1 mm. filter* 3 mm. filter at 50 kv. Skin dose (rad): 1 mm. filter* 3 mm. filter at 50 kv.
Conventional Film Without Screens
Film With Screens
50 100
5 10
850 600
42 30
* At 50 kv. for conventional film and 20 kv. for film with screens.
Vol. 132, November
Copyright© 1984 by The Williams & Wilkins Co.
Printed in U.S.A.
Original Articles INTRAOPERATIVE 3-DIMENSIONAL RADIOGRAPHY OF THE KIDNEY. MODIFIED TECHNIQUE J. M. GIL-VERNET AND A. CULLA From the Department of Urology, University of Barcelona School of Medicine, Barcelona, Spain
ABSTRACT
We present a technical modification of 3-dimensional intraoperative radiography of the kidney that reduces the cost of the material and makes preparation of the minichassis in the hospital laboratory possible. The radiogenic dose received by the kidney is 20 times less than when the system is used without screens. Previously, we reported a method of 3-dimensional intraoperative radiography of the kidney that made detection and localization of small calculi and calcifications possible with less
A
bag (fig. 1, B), which is hermetically sealed (fig. 2). The bags may be sterilized with liquids or steam. Once the x -ray has been taken the intensifying screens are recovered and can be
B
FIG. 1. A, components of minichassis. 1, plastic bags. 2, reusable intensifying screens. 3, radiographic film. 4, reusable aluminum antidiffusor. B, minichassis equipment ready for use.
exposure and larger images than those obtained with the conventional chassis. 1 In the Editorial Comment Dr. William Boyce stated his opinion that the cost of the minichassis was excessive, since the screens could not be reused and that the relative decrease in the radiogenic dose received by the kidney with our radiographic system was insignificant compared to that of the conventional chassis. We present the solution to the cost of the material plus a detailed radiogenic calibration compared to conventional radiography.
used again (fig. 3). Therefore, the only costs are for the plastic bag and film, which are minimal.* Another advantage of preparing the chassis in the hospital is that the formation of a veil and black spots on the film is avoided. These defects are produced when the screens and film remain in contact for a long time, which causes radiation to activate the phosphorus of the strengthening screens.
NEW PREPARATION TECHNIQUE
The importance of using strengthening screens lies in the fact that they reduce the exposure time by a factor of 20. This eliminates kinetic blurring (kidney movements) and the kidney receives only 1/20 of the absorbed dose of the systems without screens. Also, the radiogenic dose absorbed by the kidney is reduced by adding another 2 mm. filter to the x-ray tube, which must have a 1 mm. aluminum filter (3 mm. total). This increase in filtration lessens the hardly penetrating soft radiations com-
The minichassis consists of the previously reported elements constructed so that they can be prepared easily in the x-ray laboratory days or even hours before use (fig. 1, A). The different elements are placed inside the corresponding plastic Accepted for publication March 16, 1984. * Available from Rosex, Ciudad Balaguer, 27, Barcelona (22), Spain. 872
RADIOGENIC DOSE
873
FIG. 2. Sealing of both sides of plastic bag with bioactive equipment
pared to the more penetrating harder radiations, which increases the characteristics of the image and also diminishes the absorbed dose (see table). REFERENCE 1. Gil-Vernet, J. M. and Culla, A.: Advances in intraoperative renal
radiography: 3-dimensional radiography of the kidney. J. Urol., 125: 614, 1981.
EDITORIAL COMMENT These authors have the most immediately practical and universal technique for finding stone fragments. Presently, removal of stone fragments is an important part of the treatment of calculous disease. More than ever we seem to accept leaving behind by whathas been documented ever technique is used for removal of calculi. that infection alone or in combination with recurrent cakuli and growth of the fragments are ultimate consumers of renal functional reserve. The mere fact that we have different approaches to the removal of major calculi will not alter these complications. William H. Boyce Department of Surgery Bowman Gray School of Medicine Winston-Salem, North Carolina
FIG.
3. Minichassis placed on plate-holders
Comparison of radiation doses with and without screens
Aluminum filter characteristics (mAmp.): 1 mm. filter* 3 mm. filter at 50 kv. Skin dose (rad): 1 mm. filter* 3 mm. filter at 50 kv.
Conventional Film Without Screens
Film With Screens
50 100
5 10
850 600
42 30
* At 50 kv. for conventional film and 20 kv. for film with screens.