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Radionuclide scanning in the diagnosis of mediastinal masses
Radionuclide of
Scanning Mediastinal
in the Diagnosis Masses
By FREDERICK J. BONTE, M.D., AND THOMAS S. CURRY,III, M.D.
R
ADIOISOTOPE BLOOD POOL SCANNING was originally described by Rejali, MacIntyre, and Friedells as a test designed for identification of pericardial effusions. A number of investigators saw additional possibilities in it and soon realized that radioactive tracers could be used for any of the general diagnostic purposes of contrast roentgen angiocardiography.3*4~G~7+‘~~o We first studied mediastinal masses with blood pool scanning in 1961,” using as tracers R1311SA (radiojodinated human serum albumin) or 1311-iodipamide sodium ( Cholografin),3 and scanning with a 3-inch-crystal rectilinear unit, The nuclear physician really had to have a warm interest in this test in its earliest form, for it took quite a while, 45 minutes or so, to make a blood pool scan of the chest, and the information gained was of modest quality. But radionuclide blood pool scanning has survived its sickly childhood and has grown to robust health for two reasons: developments in instrumentation (the Anger camera1 and the high-speed large-crystal rectilinear scanner) and the evolution of favorable tracers QQmTcas pertechnetate or labeled HSA (human serum albumin; llsmIn). The radionuclide angiocardiogram, which is the modem version of the blood pool scan, may be considered to have two phases. The first is the dynamic phase, during which the moving tracer bolus is observed as it passes through the superior vena cava, the right heart, the lungs, the left heart, and the great arteries. The second is the static phase and is equivalent to the now-historic blood pool scan. Any radioisotope camera is used for the dynamic phase, and either the camera or a high-speed rectilinear scanner may be used to image the static blood pool. Dynamic
Phase
In our laboratory, the test might be done in the following manner: A patient is brought in for evaluation of a mediastinal mass, and after appropriate roentgen studies, he is placed supine beneath the detecting crystal of an Anger camera. A 12.0 mCi compact bolus of gsmTc sodium pertechnetate is injected into a right antecubital vein, and Polaroid films of the oscilloscope tube face are made with consecutive S-second exposures. Figure 1 shows three frames from such a study. We can see the normal right subclavian vein and superior FREDERICK J. BONTE, M.D.: Professor and Chairman, Department of Radiology, The University of Texas Southwestern Medical School at Dallas and Parkland Memorial Hospital and Children’s Medical Center, Dallas, Texas. THOMAS S. CURRY, III, M.D.: Assistant Professor of Radiology, Department of Radiology, The University of Texas Southwestern Medical School at Dallas and Parkland Memorial Hospital and Children’s Medical Center, Dallas, Texas. Advanced Clinical Fellow of the American Cancer Society, Inc. This work was supported in part by USPHS Grant HE-05181, and in part by a grant from the Southwestern Medical Foundation, Dallas, Texas. SEMINARS IN ROENTCENOLOGY, VOL. 4, No.
1 (JANUARY),
1969
33
BONTE
AND
CUBBY
Fig. L-Dynamic base of radionuclide angioctidiogram. A. Fi Pm made during injection
shows tracer in right subclavian vein, superior vena cava, and right atrium. B. 3 seconds later. The right ventricle? pulmonary artery, and early pulmonary arterial circulation are seen, C. 18 seconds after injection. The left ventricle and aortic arch are visible.
vena cava (Fig. lA), normal passage of blood through the right heart and pulmonary arteries (Fig. lB), and the normal pattern of the left heart and aorta (Fig. 1C ) . During the dynamic phase we can study the superior vena cava for evidence of compression and obstruction. We can also make the diagnosis of pericardial effusion by observing the distance between the pulmonary vascular bed and the cardiac pool (Fig. 2). We can identify pericardial effusions as small as 100 to 150 ml. by this method. The diagnosis can usually be made within 30 seconds, as in the case shown in Figure 2. We now believe that radionuclide angiocardiography is at least on a par with positive contrast and CO2 angiocardiography and ultrasound in accuracy, ease of employment, and low risk to the patient, and that it is now probably the method of choice for the detection of pericardial fluid. Static Phase The static phase of the study is usually performed after the patient has been moved to a rectilinear scanner. Although it may be done with a camera, we prefer the better resolution provided by a focusing-collimator-equipped rectilinear scanner with a Ei-inch crystal. Further, when we plan to superimpose the blood pool scan data upon a matching chest roentgenogram (Figs. 4C and 5C), as in the appraisal of a mediastinal tumor, we use an Ohio-Nuciear S-inch crystal rectilinear scanner and activate the “Enhancement” modality (-Figs. 4B and 5B).
RADIONUCLIDE
SCANNING
Fig. 2.-Pericardial effusion. Dynamic phase of angiocardiogram using 12.0 mCi of NaggmTc0, in a man with a superior mediastinal mass of unknown origin and probable pericardial effusion. A. Scintiphoto made during injection shows the left subclavian vein, superior vena cava, and right atrium. Note the constriction of the superior vena cava at about the level of attachment of the pericardium (arrow). B. Scintiphoto at 30 seconds shows tracer clearly defining the heart blood pool (H) separated from the lung and liver blood pools by a crescent of low radioactivity representing a large pericardial effusion.
The principle of static phase blood pool scanning in the differential diagnosis of mediastinal masses is that aneurysms should contain blood pools comparable to those of the heart and great vessels (Fig. 3) but solid tumors (Figs. 4 and 5) should not. In the absence of a major blood pool, the possibility of an aneurysm almost completely filled with clot should also be considered, but this circumstance is uncommon. When the tumor lies in the superior mediastinum, 9gmTc has another considerable advantage as a tracer because the pertechnetate ion will selectively accumulate in the thyroid gland permitting this organ to be localized with respect to the tumor (Figs. 4 and 5). If the mediastinal mass is known or thyroid carpresumed to be an extension or metastasis of a well-differentiated cinoma, a specialized scanning approach may be used. This involves rendering the tumor tissue avid for radioiodine ( 1311) by using thyroid stimulating hormone (TSH), a technic we have previously described in detail” (Figs. 6 and 7). CONCLUSION
Over the years, the blood pool scan has evolved into the radionuclide angiocardiogram, with its separate dynamic and static phases. Observation of the progress of a tracer bolus of ggmTc pertechnetate (dynamic phase) will give useful information about patency of the superior vena cava, the state of the cardiac and pulmonary circulation, and will even permit the diagnosis of a small pericardial effusion within a minute of injection.
36
BONTE
Fig.
3.-Evaluation
AND
of a right
CUBBY
midmedi-
astinal mass in an elderly man. A. Plain film. B. Static phase angiocardiogram made with a rectilinear scanner after injection of 12.0 mCi pertechnetate. The tracer in the area corresponding to the mediastinal lesion shows it to be a dilated, tortuous ascending aorta. C. Contrast angiocardiogram confirms the diagnosis.
Examination of the static blood pool by camera or rectilinear scanner will demonstrate whether a given mass contains a blood pool or not and aid in the differential diagnosis between solid tumor and aneurysm. Concentration of the pertechnetate ion in the thyroid gland permits that organ to be delineated and its relation to an upper mediastinal tumor to be determined. Of the well-differentiated thyroid carcinomas we have examined, few seemed to show much avidity for pertechnetate, but many can be made to concentrate diagnostic quantities of radioiodine after short-term stimulation with TSH. Extension, metastasis, and residual tumor can be identified by this means.
RADIOSUCLIDE
SCANSING
3
4.-AccumulaFig. tion of pertechnetate in thyroid gland. A. PA chest film of a woman with a superior mass of mediastinal unknown origin which displaces the trachea to the right. B. Static phase blood pool scan made with 12.0 mCi of pertechnetate, sodium using the Ohio-Nuclear 5-inch crystal scanner with “Enhancement.” Note the concentration of pertechnetate in the thyroid gland and the blood pool of the heart and great vessels (H). The dynamic phase was noncontributory. C. Scan superimposed upon matching chest film, , using landmarks for reorientation, shows the blood pool and the thyroid gland in rela tively normal locations. There is no significant blood pool or uptake within tl le mast s W), which later proved to be a metastasis from adenocarcinoma of the pant treas.
38
BONTE
AND
CUBRI
/ ,.
i, Fig. 5.-Use of pertechnetate in the study of a superior mediastinal tumor. A. Chest film of a 6 year old boy with a soft mass palpable in the suprasternal notch. Note the marked displacement of the trachea toward the right. B. “Enhancement” static blood pool scan made with 5.0 mCi BsmTc sodium pertechnetate. “H” is the blood pool of the heart and great vessels. Note sQmT~ in the thyroid gland. C. Scan superim osed on the chest film indicates that a dispPaced thyroid gland accounts for much of the cervical mass and part of the left superior mediastina1 shadow. A tumor (M) that does not contain tracer lies between the thyroid and the displaced trachea. Exploration showed it to be a thymic cyst.
RADIONUCLIDE
SCANNING
Fig. 6.-Thyroid tumor. PA chest film of an elderly woman with a large goiter and superior mediastinal mass. Superimposed is a scan made after 3 days of stimulation with TSH and administration of a tracer dose of 1311 sodium iodide. The scan pattern of the cervical and mediastinal mass is continuous. At operation, a large, well-differentiated follicular carcinoma almost completely replaced the thyroid gland and extended into the upper mediastinum.
Fig. 7.-Thyroid tumor. A. PA chest film of a man who had recently had a portion of a superior mediastinal mass removed. Histologic diagnosis was well-differentiated papillary and follicular thyroid carcinoma. B. Scan of neck and chest made after TSH stimulation and administration of 1311 shows functioning tumor in the right cervical lymph nodes and in nodes at the suprasternal notch. Note evidence of residual tumor in left superior mediastinum (M). Solid lines represent clavicles. All of these tumor foci were later ablated with a large therapeutic dose of 1311,
BONTE
40
AND
CURRY
REFERENCES 1. Anger, H. 0.: Gamma-ray and positron scintillation camera. Nucleonics 21:56, 1963. 2. Bonte, F. J.: Radioiodine and the child with thyroid cancer. Amer. J. Roentgen. 95:1, 1965. 3. Bonte, F. J., Andrews, G. J., Elmendorf, E. A., Presley, N. L., and Krohmer, J. S.: Radioisotope scanning in the detection of pericardial effusions. Southern Med. J. 55: 577, 1962. 4. Bonte, F. J., and Curry, T. S., III: The radioisotope blood pool scan. Amer. J. Roentgen. 96:690, 1966. 5. Bonte, F. J., Krohmer, J. S., Tseng, C. H., and Baldwin, M. C. L.: Scintillation scanning in differential diagnosis., Thoracoabdomina1 midline masses. J.A.M.A. 175: 221, 1961. 6. Holmes, R. A., and Wagner, H. N., Jr.: Delineation of blood pools. In Wagner,
EXONERATING
H. N., Jr. (Ed.) : Principles of Nuclear Medicine. PhiladeIphia, W. B. Saunders Company, 1968, pp. 563-583. 7. MacIntyre, W. J., Crespo, G. G., and Christie, J. H.: The use of radioiodinated (I-131) iodipamide for cardiovascular scanning. Amer. J. Roentgen. 89:315, 1963. 8. Rejali, A. M., MacIntyre, W. J., and Friedell, H. L.: A radioisotope method of visualization of blood pools. Amer. J. Roentgen. 79:129, 1958. 9. Sklaroff, D. M., Charkes, N. D., and Morse, D.: Measurement of pericardial fluid correlated with I-131 cholografin and IHSA heart scan. J. Nucl. Med. 5:101, 1964. 10. Wagner, H. N., Jr., McAfee, J. G., and Mozley, J. M.: Diagnosis of pericardial effusion by radioisotope scanning. Arch. Intern. Med. 108:679, 1961.
THE BURNERS
The nonmedical electrologist William Decker translated an articIe by the German medical therapist Bruno Schuermayer, which had appeared in Aerztliche Rundschau under the title, “Remarks on the Origin, Frequency, and Properties of the Roentgen Ray Bum.” The translation was published in two installments, the second of which did not even carry the name of the original author. The following passage is from the second installment, “The Relative Frequency of the X-ray Burn,” American Electrotherapeutic and X-Ray Era, 3:
266-269, 1903. “My statistics show that X-ray burns occur, but we do not know the why and wherefore. “A certain percentage of lesions and burns will always happen unless our human actions, thanks to the progress in literature and civilization, will become ideal. “But the Roentgen accidents of to-day have to be judged from the viewpoint that they are extraordinary occurrences, the prevention of which is beyond the power of the conscientious X-ray therapist. The introduction of the word misfortune in the place of carelessness will certainly be beneficial to our special branch of science.“--E.R.N. Grigg,
M.D.
Scanning Mediastinal
in the Diagnosis Masses
By FREDERICK J. BONTE, M.D., AND THOMAS S. CURRY,III, M.D.
R
ADIOISOTOPE BLOOD POOL SCANNING was originally described by Rejali, MacIntyre, and Friedells as a test designed for identification of pericardial effusions. A number of investigators saw additional possibilities in it and soon realized that radioactive tracers could be used for any of the general diagnostic purposes of contrast roentgen angiocardiography.3*4~G~7+‘~~o We first studied mediastinal masses with blood pool scanning in 1961,” using as tracers R1311SA (radiojodinated human serum albumin) or 1311-iodipamide sodium ( Cholografin),3 and scanning with a 3-inch-crystal rectilinear unit, The nuclear physician really had to have a warm interest in this test in its earliest form, for it took quite a while, 45 minutes or so, to make a blood pool scan of the chest, and the information gained was of modest quality. But radionuclide blood pool scanning has survived its sickly childhood and has grown to robust health for two reasons: developments in instrumentation (the Anger camera1 and the high-speed large-crystal rectilinear scanner) and the evolution of favorable tracers QQmTcas pertechnetate or labeled HSA (human serum albumin; llsmIn). The radionuclide angiocardiogram, which is the modem version of the blood pool scan, may be considered to have two phases. The first is the dynamic phase, during which the moving tracer bolus is observed as it passes through the superior vena cava, the right heart, the lungs, the left heart, and the great arteries. The second is the static phase and is equivalent to the now-historic blood pool scan. Any radioisotope camera is used for the dynamic phase, and either the camera or a high-speed rectilinear scanner may be used to image the static blood pool. Dynamic
Phase
In our laboratory, the test might be done in the following manner: A patient is brought in for evaluation of a mediastinal mass, and after appropriate roentgen studies, he is placed supine beneath the detecting crystal of an Anger camera. A 12.0 mCi compact bolus of gsmTc sodium pertechnetate is injected into a right antecubital vein, and Polaroid films of the oscilloscope tube face are made with consecutive S-second exposures. Figure 1 shows three frames from such a study. We can see the normal right subclavian vein and superior FREDERICK J. BONTE, M.D.: Professor and Chairman, Department of Radiology, The University of Texas Southwestern Medical School at Dallas and Parkland Memorial Hospital and Children’s Medical Center, Dallas, Texas. THOMAS S. CURRY, III, M.D.: Assistant Professor of Radiology, Department of Radiology, The University of Texas Southwestern Medical School at Dallas and Parkland Memorial Hospital and Children’s Medical Center, Dallas, Texas. Advanced Clinical Fellow of the American Cancer Society, Inc. This work was supported in part by USPHS Grant HE-05181, and in part by a grant from the Southwestern Medical Foundation, Dallas, Texas. SEMINARS IN ROENTCENOLOGY, VOL. 4, No.
1 (JANUARY),
1969
33
BONTE
AND
CUBBY
Fig. L-Dynamic base of radionuclide angioctidiogram. A. Fi Pm made during injection
shows tracer in right subclavian vein, superior vena cava, and right atrium. B. 3 seconds later. The right ventricle? pulmonary artery, and early pulmonary arterial circulation are seen, C. 18 seconds after injection. The left ventricle and aortic arch are visible.
vena cava (Fig. lA), normal passage of blood through the right heart and pulmonary arteries (Fig. lB), and the normal pattern of the left heart and aorta (Fig. 1C ) . During the dynamic phase we can study the superior vena cava for evidence of compression and obstruction. We can also make the diagnosis of pericardial effusion by observing the distance between the pulmonary vascular bed and the cardiac pool (Fig. 2). We can identify pericardial effusions as small as 100 to 150 ml. by this method. The diagnosis can usually be made within 30 seconds, as in the case shown in Figure 2. We now believe that radionuclide angiocardiography is at least on a par with positive contrast and CO2 angiocardiography and ultrasound in accuracy, ease of employment, and low risk to the patient, and that it is now probably the method of choice for the detection of pericardial fluid. Static Phase The static phase of the study is usually performed after the patient has been moved to a rectilinear scanner. Although it may be done with a camera, we prefer the better resolution provided by a focusing-collimator-equipped rectilinear scanner with a Ei-inch crystal. Further, when we plan to superimpose the blood pool scan data upon a matching chest roentgenogram (Figs. 4C and 5C), as in the appraisal of a mediastinal tumor, we use an Ohio-Nuciear S-inch crystal rectilinear scanner and activate the “Enhancement” modality (-Figs. 4B and 5B).
RADIONUCLIDE
SCANNING
Fig. 2.-Pericardial effusion. Dynamic phase of angiocardiogram using 12.0 mCi of NaggmTc0, in a man with a superior mediastinal mass of unknown origin and probable pericardial effusion. A. Scintiphoto made during injection shows the left subclavian vein, superior vena cava, and right atrium. Note the constriction of the superior vena cava at about the level of attachment of the pericardium (arrow). B. Scintiphoto at 30 seconds shows tracer clearly defining the heart blood pool (H) separated from the lung and liver blood pools by a crescent of low radioactivity representing a large pericardial effusion.
The principle of static phase blood pool scanning in the differential diagnosis of mediastinal masses is that aneurysms should contain blood pools comparable to those of the heart and great vessels (Fig. 3) but solid tumors (Figs. 4 and 5) should not. In the absence of a major blood pool, the possibility of an aneurysm almost completely filled with clot should also be considered, but this circumstance is uncommon. When the tumor lies in the superior mediastinum, 9gmTc has another considerable advantage as a tracer because the pertechnetate ion will selectively accumulate in the thyroid gland permitting this organ to be localized with respect to the tumor (Figs. 4 and 5). If the mediastinal mass is known or thyroid carpresumed to be an extension or metastasis of a well-differentiated cinoma, a specialized scanning approach may be used. This involves rendering the tumor tissue avid for radioiodine ( 1311) by using thyroid stimulating hormone (TSH), a technic we have previously described in detail” (Figs. 6 and 7). CONCLUSION
Over the years, the blood pool scan has evolved into the radionuclide angiocardiogram, with its separate dynamic and static phases. Observation of the progress of a tracer bolus of ggmTc pertechnetate (dynamic phase) will give useful information about patency of the superior vena cava, the state of the cardiac and pulmonary circulation, and will even permit the diagnosis of a small pericardial effusion within a minute of injection.
36
BONTE
Fig.
3.-Evaluation
AND
of a right
CUBBY
midmedi-
astinal mass in an elderly man. A. Plain film. B. Static phase angiocardiogram made with a rectilinear scanner after injection of 12.0 mCi pertechnetate. The tracer in the area corresponding to the mediastinal lesion shows it to be a dilated, tortuous ascending aorta. C. Contrast angiocardiogram confirms the diagnosis.
Examination of the static blood pool by camera or rectilinear scanner will demonstrate whether a given mass contains a blood pool or not and aid in the differential diagnosis between solid tumor and aneurysm. Concentration of the pertechnetate ion in the thyroid gland permits that organ to be delineated and its relation to an upper mediastinal tumor to be determined. Of the well-differentiated thyroid carcinomas we have examined, few seemed to show much avidity for pertechnetate, but many can be made to concentrate diagnostic quantities of radioiodine after short-term stimulation with TSH. Extension, metastasis, and residual tumor can be identified by this means.
RADIOSUCLIDE
SCANSING
3
4.-AccumulaFig. tion of pertechnetate in thyroid gland. A. PA chest film of a woman with a superior mass of mediastinal unknown origin which displaces the trachea to the right. B. Static phase blood pool scan made with 12.0 mCi of pertechnetate, sodium using the Ohio-Nuclear 5-inch crystal scanner with “Enhancement.” Note the concentration of pertechnetate in the thyroid gland and the blood pool of the heart and great vessels (H). The dynamic phase was noncontributory. C. Scan superimposed upon matching chest film, , using landmarks for reorientation, shows the blood pool and the thyroid gland in rela tively normal locations. There is no significant blood pool or uptake within tl le mast s W), which later proved to be a metastasis from adenocarcinoma of the pant treas.
38
BONTE
AND
CUBRI
/ ,.
i, Fig. 5.-Use of pertechnetate in the study of a superior mediastinal tumor. A. Chest film of a 6 year old boy with a soft mass palpable in the suprasternal notch. Note the marked displacement of the trachea toward the right. B. “Enhancement” static blood pool scan made with 5.0 mCi BsmTc sodium pertechnetate. “H” is the blood pool of the heart and great vessels. Note sQmT~ in the thyroid gland. C. Scan superim osed on the chest film indicates that a dispPaced thyroid gland accounts for much of the cervical mass and part of the left superior mediastina1 shadow. A tumor (M) that does not contain tracer lies between the thyroid and the displaced trachea. Exploration showed it to be a thymic cyst.
RADIONUCLIDE
SCANNING
Fig. 6.-Thyroid tumor. PA chest film of an elderly woman with a large goiter and superior mediastinal mass. Superimposed is a scan made after 3 days of stimulation with TSH and administration of a tracer dose of 1311 sodium iodide. The scan pattern of the cervical and mediastinal mass is continuous. At operation, a large, well-differentiated follicular carcinoma almost completely replaced the thyroid gland and extended into the upper mediastinum.
Fig. 7.-Thyroid tumor. A. PA chest film of a man who had recently had a portion of a superior mediastinal mass removed. Histologic diagnosis was well-differentiated papillary and follicular thyroid carcinoma. B. Scan of neck and chest made after TSH stimulation and administration of 1311 shows functioning tumor in the right cervical lymph nodes and in nodes at the suprasternal notch. Note evidence of residual tumor in left superior mediastinum (M). Solid lines represent clavicles. All of these tumor foci were later ablated with a large therapeutic dose of 1311,
BONTE
40
AND
CURRY
REFERENCES 1. Anger, H. 0.: Gamma-ray and positron scintillation camera. Nucleonics 21:56, 1963. 2. Bonte, F. J.: Radioiodine and the child with thyroid cancer. Amer. J. Roentgen. 95:1, 1965. 3. Bonte, F. J., Andrews, G. J., Elmendorf, E. A., Presley, N. L., and Krohmer, J. S.: Radioisotope scanning in the detection of pericardial effusions. Southern Med. J. 55: 577, 1962. 4. Bonte, F. J., and Curry, T. S., III: The radioisotope blood pool scan. Amer. J. Roentgen. 96:690, 1966. 5. Bonte, F. J., Krohmer, J. S., Tseng, C. H., and Baldwin, M. C. L.: Scintillation scanning in differential diagnosis., Thoracoabdomina1 midline masses. J.A.M.A. 175: 221, 1961. 6. Holmes, R. A., and Wagner, H. N., Jr.: Delineation of blood pools. In Wagner,
EXONERATING
H. N., Jr. (Ed.) : Principles of Nuclear Medicine. PhiladeIphia, W. B. Saunders Company, 1968, pp. 563-583. 7. MacIntyre, W. J., Crespo, G. G., and Christie, J. H.: The use of radioiodinated (I-131) iodipamide for cardiovascular scanning. Amer. J. Roentgen. 89:315, 1963. 8. Rejali, A. M., MacIntyre, W. J., and Friedell, H. L.: A radioisotope method of visualization of blood pools. Amer. J. Roentgen. 79:129, 1958. 9. Sklaroff, D. M., Charkes, N. D., and Morse, D.: Measurement of pericardial fluid correlated with I-131 cholografin and IHSA heart scan. J. Nucl. Med. 5:101, 1964. 10. Wagner, H. N., Jr., McAfee, J. G., and Mozley, J. M.: Diagnosis of pericardial effusion by radioisotope scanning. Arch. Intern. Med. 108:679, 1961.
THE BURNERS
The nonmedical electrologist William Decker translated an articIe by the German medical therapist Bruno Schuermayer, which had appeared in Aerztliche Rundschau under the title, “Remarks on the Origin, Frequency, and Properties of the Roentgen Ray Bum.” The translation was published in two installments, the second of which did not even carry the name of the original author. The following passage is from the second installment, “The Relative Frequency of the X-ray Burn,” American Electrotherapeutic and X-Ray Era, 3:
266-269, 1903. “My statistics show that X-ray burns occur, but we do not know the why and wherefore. “A certain percentage of lesions and burns will always happen unless our human actions, thanks to the progress in literature and civilization, will become ideal. “But the Roentgen accidents of to-day have to be judged from the viewpoint that they are extraordinary occurrences, the prevention of which is beyond the power of the conscientious X-ray therapist. The introduction of the word misfortune in the place of carelessness will certainly be beneficial to our special branch of science.“--E.R.N. Grigg,
M.D.