FROM THE DEPARTMENT OF DIAGNOSTIC RADIOLOGY
III
(DIRECTOR: C.-G. HELANDER),
SAHLGRENSKA SJUKHUSET, S-411 32 GOTHENBURG, SWEDEN.
SOFT TISSUE XERORADIOGRAPHY OF THE SHOULDER JOINT S. REICHMANN, K. ASTRAND, E. DEICHGRABER and B. OLSSON Originally it was LEB (1961) who suggested that peritendinitis of the shoulder could be demonstrated by means of soft tissue films. However, he did not refine his technique, nor did he publish any figures concerning the reliability of the method. DEICHGRABER & OLSSON (1975) presented a technique arrived at by means of systematic experiments. When this technique was used in patients with shoulder pains, the presence of soft tissue oedema and displacement of the deltoid muscle were found to correspond with clinical signs of peritendinits. Industrial non-screen film of medium sensitivity and with a high silver content was used, as such a film was found to be superior for soft tissue radiography by DE1CHGRABER et colI. (1974). A later attempt to use screen-film combinations of higher sensitivity in order to reduce the radiation dose to the patient failed; the image quality was too much impaired (DEICHGRABER et colI. 1975). Likewise, K-edge filtering in combination with a tungsten target tube did not give any dose reduction (DEICHGRABER & REICHMANN 1975). Aluminium filtration, on the other hand, reduced the incident dose to the patient to about 60 per cent without affecting image contrast. Unfortunately, this filtration led to such increase in the exposure times as to be of dubious value. Reports indicating the xeroradiographic medium to be useful in soft tissue radiography have appeared (WOLFE 1968, BOAG et colI. 1972) but the ability of the xerox Submitted for publication 3 April 1975.
572
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SOFT TISSUE XERORADIOGRAPHY OF THE SHOULDER JOINT
573
a b Fig. 1. Detail of shoulder joint with massive calcification of the subdeltoid bursa. a) Negative, b) positive development. A bright halo exists around the calcification in (b) which is not present in (a).
plate to record the oedematous blurring of a fatty layer has not been fully analysed. The xerox plate tends to display contours alone so that the surroundings on both sides of the contour differ but little in blackening. This effect is called edge contrast enhancement. The diagnostic information inherent in an inflammatory blurring of fat tissue rarely gives rise to contours, and so it appeared justified to compare the xerox technique with that of DEICHGRABER & OLSSON (1975), replacing the film by the plate. Experiments
Preliminary experiments were carried out in order to develop a technique that could be systematically compared with the industrial film technique. Plates manufactured by the Rank Xerox corp. were used (system 125). The electrostatic loading before exposure can be set at four levels. The highest loading (D) was empirically found to be recommendable. The development can be performed in a negative and a positive fashion, the former giving rise to bright image areas where the object attenuation is high. The two modes of development were not of identical value (Fig. 1). The edge contrast enhancement implies formation of double contours wherever contours are formed. Thus a contour in a xerox plate always has a bright and a dark component side by side. The bright component was broader, appearing as a sort of halo. With negative development (Fig. 1 a) the halo deriving from high-absorbing
Downloaded from acr.sagepub.com by guest on July 25, 2015
574
S. REICHMANN,
K.
ASTRAND, E. DEICHGRABER AND B. OLSSON
a b Fig. 2. Xeroradiography. a) Shoulder joint without abnormality and b) with extensive blurring of the fatty layer. The subdeltoid fatty layer (-) is only partly visible in (b) due to the presence of inflammatory oedema.
structures was superimposed upon these structures and not the tissues surrounding them, as was the case with positive development (Fig. 1 b). Similar observations have been made with respect to osteosynthesis materials by FRIEDMANN et colI. (1974). Thus negative development was found preferable. It is well known that the xerox plate tolerates higher tube potentials and higher levels of secondary radiation than film (SCHERTE'L et colI. 1974, SELIN et colI. 1975). A phantom consisting of nylon wires of different dimensions in a 7 em layer of vegetable oil was used to find out the appropriate tube potential. Agfa-Gevaert Mamoray T 3 industrial film was exposed with 40 kV tungsten target and 0.5 mm Al total filtration and the xerox plates with potentials between 40 and 110 kV. A tube potential- of 110 kV appeared to give similar visibility of the wires on xerox plates as 40 kV on industrial films. However, a lower potential was chosen for the definite testing for two reasons. Initial clinical examinations indicated that the demonstration of fat tissue blurring would require softer radiation with the xerox plate than was suggested by the phantom experiments, where only sharp contours were recorded. Secondly, previous experience. (DEICHGRABER & OLSSON) had suggested that although the signal/noise ratio in the film technique was acceptable, a certain improvement was still to be desired. Thus, a final potential of 60 kV was arrived at. This was combined with 2 mm Al as total filtration. The final comparison between the two techniques was carried out in 22 patients
Downloaded from acr.sagepub.com by guest on July 25, 2015
SOFT TISSUE XERORADIOGRAPHY OF THE SHOULDER JOINT
575
(8 males, 14 females, aged 14 to 86 years) with pains in the shoulder region. In one subject both shoulders were examined; thus, the material consisted of 23 joints, 13 right sided. With each technique two a.p. views were obtained, one with the shoulder joint in internal and one in external rotation. The patients had to be repositioned when the recording medium was changed. Thus, the film and xerox views were not quite identical. Still, it was possible to determine whether the two different examinations would give the same diagnosis. Corresponding results were obtained with the two methods except in one case where the films gave evidence of a strictly localized blurring of the subdeltoid fatty layer, not detected in the xerox plate. Slight projection differences might have caused this effect, since small blurrings were otherwise detectable in the xerox plates as well. A normal and a blurred fatty layer are demonstrated in Fig. 2. In the whole material a blurring was noted in 14 joints. The film technique has been found to give an average dose of 0.42 rad per image. By means of an ionization chamber the relative dose was measured for the xerox technique. The average dose was found to be 0.16 rad per image, the reduction being 0.26 rad per image in absolute figures, i.e. a reduction of 62 per cent.
Discussion
The experiences gained indicate that xeroradiography makes possible soft tissue examinations of the shoulder at a lower dose level and with less tube load than any good film technique availabe today. The reliability of the xerox method appears to be the same as that of the film technique by the method of DEICHGRABER & OLSSON. No loss of quality occurred despite the dose reduction. The lowered tube load of xeroradiography means an important advantage. With the film technique used, a total filtration of 2.25 mm Al was to be preferred as it gave a marked dose reduction without lowering the image contrast (DEICHGRABER & REICHMANN). However, this filtration tended to make the exposure times too long, why the lower filtration of 0.5 mm Al had to be accepted. An important part of the dose reduction obtained with the xerox plate is due to the increased filtration. This filtration (2 mm AI) is standard in conventional roentgen tubes, which means that no other special equipment is required than the xerox plates and their loading and developing machines.
SUMMARY Soft tissue xeroradiography of the shoulder joint has been compared with a film technique arrived at previously. The xerox plates gave a lower radiation dose to the patient without loss of information. The film technique requires a tungsten target tube with an extra thin glass window ( = 0.5 mm AI), while the xerox technique may be used with standard tubes.
Downloaded from acr.sagepub.com by guest on July 25, 2015
576
S. REICHMANN, K. ASTRAND, E. DEICHGRABER AND B. OLSSON
ZUSAMMENFASSUNG Die Weichgewebe-Xeroradiographie des Schultergelenks wurde mit einer zuvor ausgearbeiteten Film-Technik verglichen. Die Xerox-Filme gaben dem Patienten eine niedrigere Strahlen-Dosis ohne Verlust von Information. Die Film-Technik verlangt eine TungstenSchussziel-Rohre mit einem besonders diinnen Glas-Fenster (=0,5 mm AI), wahrend bei der Xeroxtechnik Standard-Rohren verwendet werden konnen.
RESUME Les auteurs ont compare la xeroradiographie des tissus mous de I'articulation de I'epaule avec une technique utilisant un film qu'ils avaient mise au point prealablement, Les plaques xerox permettent de diminuer la dose de radiation au malade sans perte d'information. La technique avec film necessite un tube a anode en tungstene avec une Ienetre de verre tres fin ( ~ 0,5 mm AI), alors que la technique xerox peut etre utilisee avec des tubes ordinaires.
REFERENCES BOAG J. W., STACEY B. and DAVIS R.: Xerographic recording of mammograms. Brit. J. Radiol. 45 (1972), 633. DEICHGRABER E. and OLSSON B.: Soft tissue radiography in painful shoulder. Acta radiol. Diagnosis 16 (1975), 393. - and REICHMANN S.: Filtration in soft tissue radiography. Acta radiol. Diagnosis 16 (1975), 248. - - and BUREN M.: Film quality in mammary radiography. Acta radiol. Diagnosis 15 (1974), 93. - - and STRID K.-G.: Intensifying screens in soft tissue radiography. Acta radiol. Diagnosis 16 (1975), 54. FRIEDMANN G., MOODER U. und TISMER R.: Xeroradiographische Befunde bei osteosynthetisch versorgten Frakturen. Rontgen-Bl. 27 (1974), 586. LEB A.: Der rontgendiagnostische Beitrag zur Diagnose der Periarthrose und unspezifischen Periarthritis. Wien. klin. Wschr. 73 (1961), 141. SCHERTEL L., ZUM WINKEL K. und SOULIER W.: Xeroradiographische Urographie und Cholezysto-Cholangiographie. Rontgen-Bl. 27 (1974), 575. SELIN K., DEICHGRABER E. and REICHMANN S.: Influence of secondary radiation on image quality. Acta radiol. Diagnosis 16 (1975), 520. WOLFE J. N.: Xerography of the breast. Radiology 91 (1968),231.
Downloaded from acr.sagepub.com by guest on July 25, 2015
III
(DIRECTOR: C.-G. HELANDER),
SAHLGRENSKA SJUKHUSET, S-411 32 GOTHENBURG, SWEDEN.
SOFT TISSUE XERORADIOGRAPHY OF THE SHOULDER JOINT S. REICHMANN, K. ASTRAND, E. DEICHGRABER and B. OLSSON Originally it was LEB (1961) who suggested that peritendinitis of the shoulder could be demonstrated by means of soft tissue films. However, he did not refine his technique, nor did he publish any figures concerning the reliability of the method. DEICHGRABER & OLSSON (1975) presented a technique arrived at by means of systematic experiments. When this technique was used in patients with shoulder pains, the presence of soft tissue oedema and displacement of the deltoid muscle were found to correspond with clinical signs of peritendinits. Industrial non-screen film of medium sensitivity and with a high silver content was used, as such a film was found to be superior for soft tissue radiography by DE1CHGRABER et colI. (1974). A later attempt to use screen-film combinations of higher sensitivity in order to reduce the radiation dose to the patient failed; the image quality was too much impaired (DEICHGRABER et colI. 1975). Likewise, K-edge filtering in combination with a tungsten target tube did not give any dose reduction (DEICHGRABER & REICHMANN 1975). Aluminium filtration, on the other hand, reduced the incident dose to the patient to about 60 per cent without affecting image contrast. Unfortunately, this filtration led to such increase in the exposure times as to be of dubious value. Reports indicating the xeroradiographic medium to be useful in soft tissue radiography have appeared (WOLFE 1968, BOAG et colI. 1972) but the ability of the xerox Submitted for publication 3 April 1975.
572
Downloaded from acr.sagepub.com by guest on July 25, 2015
SOFT TISSUE XERORADIOGRAPHY OF THE SHOULDER JOINT
573
a b Fig. 1. Detail of shoulder joint with massive calcification of the subdeltoid bursa. a) Negative, b) positive development. A bright halo exists around the calcification in (b) which is not present in (a).
plate to record the oedematous blurring of a fatty layer has not been fully analysed. The xerox plate tends to display contours alone so that the surroundings on both sides of the contour differ but little in blackening. This effect is called edge contrast enhancement. The diagnostic information inherent in an inflammatory blurring of fat tissue rarely gives rise to contours, and so it appeared justified to compare the xerox technique with that of DEICHGRABER & OLSSON (1975), replacing the film by the plate. Experiments
Preliminary experiments were carried out in order to develop a technique that could be systematically compared with the industrial film technique. Plates manufactured by the Rank Xerox corp. were used (system 125). The electrostatic loading before exposure can be set at four levels. The highest loading (D) was empirically found to be recommendable. The development can be performed in a negative and a positive fashion, the former giving rise to bright image areas where the object attenuation is high. The two modes of development were not of identical value (Fig. 1). The edge contrast enhancement implies formation of double contours wherever contours are formed. Thus a contour in a xerox plate always has a bright and a dark component side by side. The bright component was broader, appearing as a sort of halo. With negative development (Fig. 1 a) the halo deriving from high-absorbing
Downloaded from acr.sagepub.com by guest on July 25, 2015
574
S. REICHMANN,
K.
ASTRAND, E. DEICHGRABER AND B. OLSSON
a b Fig. 2. Xeroradiography. a) Shoulder joint without abnormality and b) with extensive blurring of the fatty layer. The subdeltoid fatty layer (-) is only partly visible in (b) due to the presence of inflammatory oedema.
structures was superimposed upon these structures and not the tissues surrounding them, as was the case with positive development (Fig. 1 b). Similar observations have been made with respect to osteosynthesis materials by FRIEDMANN et colI. (1974). Thus negative development was found preferable. It is well known that the xerox plate tolerates higher tube potentials and higher levels of secondary radiation than film (SCHERTE'L et colI. 1974, SELIN et colI. 1975). A phantom consisting of nylon wires of different dimensions in a 7 em layer of vegetable oil was used to find out the appropriate tube potential. Agfa-Gevaert Mamoray T 3 industrial film was exposed with 40 kV tungsten target and 0.5 mm Al total filtration and the xerox plates with potentials between 40 and 110 kV. A tube potential- of 110 kV appeared to give similar visibility of the wires on xerox plates as 40 kV on industrial films. However, a lower potential was chosen for the definite testing for two reasons. Initial clinical examinations indicated that the demonstration of fat tissue blurring would require softer radiation with the xerox plate than was suggested by the phantom experiments, where only sharp contours were recorded. Secondly, previous experience. (DEICHGRABER & OLSSON) had suggested that although the signal/noise ratio in the film technique was acceptable, a certain improvement was still to be desired. Thus, a final potential of 60 kV was arrived at. This was combined with 2 mm Al as total filtration. The final comparison between the two techniques was carried out in 22 patients
Downloaded from acr.sagepub.com by guest on July 25, 2015
SOFT TISSUE XERORADIOGRAPHY OF THE SHOULDER JOINT
575
(8 males, 14 females, aged 14 to 86 years) with pains in the shoulder region. In one subject both shoulders were examined; thus, the material consisted of 23 joints, 13 right sided. With each technique two a.p. views were obtained, one with the shoulder joint in internal and one in external rotation. The patients had to be repositioned when the recording medium was changed. Thus, the film and xerox views were not quite identical. Still, it was possible to determine whether the two different examinations would give the same diagnosis. Corresponding results were obtained with the two methods except in one case where the films gave evidence of a strictly localized blurring of the subdeltoid fatty layer, not detected in the xerox plate. Slight projection differences might have caused this effect, since small blurrings were otherwise detectable in the xerox plates as well. A normal and a blurred fatty layer are demonstrated in Fig. 2. In the whole material a blurring was noted in 14 joints. The film technique has been found to give an average dose of 0.42 rad per image. By means of an ionization chamber the relative dose was measured for the xerox technique. The average dose was found to be 0.16 rad per image, the reduction being 0.26 rad per image in absolute figures, i.e. a reduction of 62 per cent.
Discussion
The experiences gained indicate that xeroradiography makes possible soft tissue examinations of the shoulder at a lower dose level and with less tube load than any good film technique availabe today. The reliability of the xerox method appears to be the same as that of the film technique by the method of DEICHGRABER & OLSSON. No loss of quality occurred despite the dose reduction. The lowered tube load of xeroradiography means an important advantage. With the film technique used, a total filtration of 2.25 mm Al was to be preferred as it gave a marked dose reduction without lowering the image contrast (DEICHGRABER & REICHMANN). However, this filtration tended to make the exposure times too long, why the lower filtration of 0.5 mm Al had to be accepted. An important part of the dose reduction obtained with the xerox plate is due to the increased filtration. This filtration (2 mm AI) is standard in conventional roentgen tubes, which means that no other special equipment is required than the xerox plates and their loading and developing machines.
SUMMARY Soft tissue xeroradiography of the shoulder joint has been compared with a film technique arrived at previously. The xerox plates gave a lower radiation dose to the patient without loss of information. The film technique requires a tungsten target tube with an extra thin glass window ( = 0.5 mm AI), while the xerox technique may be used with standard tubes.
Downloaded from acr.sagepub.com by guest on July 25, 2015
576
S. REICHMANN, K. ASTRAND, E. DEICHGRABER AND B. OLSSON
ZUSAMMENFASSUNG Die Weichgewebe-Xeroradiographie des Schultergelenks wurde mit einer zuvor ausgearbeiteten Film-Technik verglichen. Die Xerox-Filme gaben dem Patienten eine niedrigere Strahlen-Dosis ohne Verlust von Information. Die Film-Technik verlangt eine TungstenSchussziel-Rohre mit einem besonders diinnen Glas-Fenster (=0,5 mm AI), wahrend bei der Xeroxtechnik Standard-Rohren verwendet werden konnen.
RESUME Les auteurs ont compare la xeroradiographie des tissus mous de I'articulation de I'epaule avec une technique utilisant un film qu'ils avaient mise au point prealablement, Les plaques xerox permettent de diminuer la dose de radiation au malade sans perte d'information. La technique avec film necessite un tube a anode en tungstene avec une Ienetre de verre tres fin ( ~ 0,5 mm AI), alors que la technique xerox peut etre utilisee avec des tubes ordinaires.
REFERENCES BOAG J. W., STACEY B. and DAVIS R.: Xerographic recording of mammograms. Brit. J. Radiol. 45 (1972), 633. DEICHGRABER E. and OLSSON B.: Soft tissue radiography in painful shoulder. Acta radiol. Diagnosis 16 (1975), 393. - and REICHMANN S.: Filtration in soft tissue radiography. Acta radiol. Diagnosis 16 (1975), 248. - - and BUREN M.: Film quality in mammary radiography. Acta radiol. Diagnosis 15 (1974), 93. - - and STRID K.-G.: Intensifying screens in soft tissue radiography. Acta radiol. Diagnosis 16 (1975), 54. FRIEDMANN G., MOODER U. und TISMER R.: Xeroradiographische Befunde bei osteosynthetisch versorgten Frakturen. Rontgen-Bl. 27 (1974), 586. LEB A.: Der rontgendiagnostische Beitrag zur Diagnose der Periarthrose und unspezifischen Periarthritis. Wien. klin. Wschr. 73 (1961), 141. SCHERTEL L., ZUM WINKEL K. und SOULIER W.: Xeroradiographische Urographie und Cholezysto-Cholangiographie. Rontgen-Bl. 27 (1974), 575. SELIN K., DEICHGRABER E. and REICHMANN S.: Influence of secondary radiation on image quality. Acta radiol. Diagnosis 16 (1975), 520. WOLFE J. N.: Xerography of the breast. Radiology 91 (1968),231.
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