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Clinical Breast Lymphoscintigraphy: Optimal Techniques for Performing Studies, Image Atlas, and Analysis of Images¹

¹ From the Department of Radiology, Mount Sinai School of Medicine, New York, NY. Received August 14, 2002; revision requested November 18; final revision received August 21, 2003; accepted August 22. All authors have no financial relationships to disclose. Address correspondence to B.R.K., Department of Radiology, Box 1141, Mount Sinai Medical Center, One Gustave L. Levy Pl, New York, NY 10029-6574 (e-mail: syrob@msn.com).

View larger version (28K): [in a new window]   Figure 1.  Different sites of injection. Right: Drawing shows multiple potential injection sites in the right breast, with the injection patterns altered when close to the axilla. A, For uncomplicated lesions, injections can be performed at two to four perilesional locations. B, Lumpectomy sites can be injected at two to six locations, with a minimum of one injection on each side of the scar. C, When lesions are close to the axilla, it is reasonable to shift portions of the total injected dose away from the regions closest to the axilla to diminish the negative effects of injection site diffusion, which could hide adjacent SNs. Top left: Dermal injections are usually performed at the skin directly above the lesion, whereas areolar injections can be performed anywhere in the areola or at the aspect of the areolar-cutaneous junction closest to the lesion.

View larger version (124K): [in a new window]   Figure 2a.  (a) Anterior midstudy image of the left breast, obtained after concurrent perilesional and intradermal injections, shows a tortuous lymphatic pathway leading to the SN from the injection sites (IS). (b) Anterior end-of-study image of the right side of the chest, obtained in another patient after injections into the upper (U) and lower (L) tissues flanking a lumpectomy scar and at the areolar-cutaneous junction (arrow), shows several nodes in the axilla (SNs).

View larger version (124K): [in a new window]   Figure 2b.  (a) Anterior midstudy image of the left breast, obtained after concurrent perilesional and intradermal injections, shows a tortuous lymphatic pathway leading to the SN from the injection sites (IS). (b) Anterior end-of-study image of the right side of the chest, obtained in another patient after injections into the upper (U) and lower (L) tissues flanking a lumpectomy scar and at the areolar-cutaneous junction (arrow), shows several nodes in the axilla (SNs).

View larger version (141K): [in a new window]   Figure 3.  Importance of multiangle views in assessing overlap. Top: Anterior and lateral backlit end-of-study images of the left side of the chest show the injection sites (IS) and SNs. An internal mammary SN (IM) is also noted. Bottom: Images show an overlap effect for both the injection sites and the SNs, depending on the view.

View larger version (121K): [in a new window]   Figure 4a.  Sequence of consecutive anterior images. (a) Image obtained before "LymphoBoost" (LB) injection (injection at the areolar-cutaneous junction) shows a perilesional injection site (IS), internal mammary SNs (IM), and an axillary SN (arrow). The liver activity is due to capillary penetration or partial vascularization of the radiotracer dose during injections. (b) Image obtained after lymphoboost (LB) injection shows marked augmentation of axillary SN activity with additional nodes noted (arrow). (c, d) Images obtained with the arm up (c) or down (d) show a marked effect of arm position on the perceived locations of the SNs and the injection site with a potential corresponding shift in the surface markings. The position of the internal mammary SNs (arrow) remains fixed. (Reprinted, with permission, from reference 5.)

View larger version (127K): [in a new window]   Figure 4b.  Sequence of consecutive anterior images. (a) Image obtained before "LymphoBoost" (LB) injection (injection at the areolar-cutaneous junction) shows a perilesional injection site (IS), internal mammary SNs (IM), and an axillary SN (arrow). The liver activity is due to capillary penetration or partial vascularization of the radiotracer dose during injections. (b) Image obtained after lymphoboost (LB) injection shows marked augmentation of axillary SN activity with additional nodes noted (arrow). (c, d) Images obtained with the arm up (c) or down (d) show a marked effect of arm position on the perceived locations of the SNs and the injection site with a potential corresponding shift in the surface markings. The position of the internal mammary SNs (arrow) remains fixed. (Reprinted, with permission, from reference 5.)

View larger version (152K): [in a new window]   Figure 4c.  Sequence of consecutive anterior images. (a) Image obtained before "LymphoBoost" (LB) injection (injection at the areolar-cutaneous junction) shows a perilesional injection site (IS), internal mammary SNs (IM), and an axillary SN (arrow). The liver activity is due to capillary penetration or partial vascularization of the radiotracer dose during injections. (b) Image obtained after lymphoboost (LB) injection shows marked augmentation of axillary SN activity with additional nodes noted (arrow). (c, d) Images obtained with the arm up (c) or down (d) show a marked effect of arm position on the perceived locations of the SNs and the injection site with a potential corresponding shift in the surface markings. The position of the internal mammary SNs (arrow) remains fixed. (Reprinted, with permission, from reference 5.)

View larger version (129K): [in a new window]   Figure 4d.  Sequence of consecutive anterior images. (a) Image obtained before "LymphoBoost" (LB) injection (injection at the areolar-cutaneous junction) shows a perilesional injection site (IS), internal mammary SNs (IM), and an axillary SN (arrow). The liver activity is due to capillary penetration or partial vascularization of the radiotracer dose during injections. (b) Image obtained after lymphoboost (LB) injection shows marked augmentation of axillary SN activity with additional nodes noted (arrow). (c, d) Images obtained with the arm up (c) or down (d) show a marked effect of arm position on the perceived locations of the SNs and the injection site with a potential corresponding shift in the surface markings. The position of the internal mammary SNs (arrow) remains fixed. (Reprinted, with permission, from reference 5.)

View larger version (83K): [in a new window]   Figure 5a.  Potential connections between lymph nodes and lymphatic channels. (a) Drawing of a lymph node shows serial connections to germinal centers and alternate connections that mostly bypass the germinal centers, running through the node or on the surface without connecting (19). (b) Diagrams show a serial connection (which is most common) and an alternate parallel connection, which has reduced flow compared with that of serial connections. (c) Anterior midstudy image of the left side of the chest, obtained after perilesional and skin injections, shows a bright focus and a fainter focus (arrow), which appeared simultaneously. The latter is closer to the tumor in the breast and potentially represents a node fed through a side parallel connection or a node that is only partially visualized due to replacement by metastases. Because the fainter focus intensified over time and persisted on delayed views, ectasia was less likely. (d) Diagrams show possible connections between a tumor and lymph nodes. PL = perilesional injection site. 1, Perilesional injection demonstrates the SN and a more distant axillary echelon node. 2, Surface injection leads to augmentation of the nodes seen after the perilesional injection. EN = echelon node. 3, Surface injection leads to augmentation of the nodes seen after the perilesional injection, with additional foci appearing proximally, upstream from the originally delineated SNs. This appearance could represent pooling of activity in a dilated area, that is, a pseudo-SN (PSN) or a reverse echelon node (REN). A reverse echelon node is an upstream node that is distinct from the primary SN seen after the initial perilesional injection and that receives activity only from the surface injection. It is usually closer to the tumor and technically is not part of the tumor drainage, since it is not seen with the original perilesional injection but only after the surface injection. The more distant true SN is almost always augmented by surface injections, since it is downstream along the lymphatic chain. 4, Surface injection leads to activity bypassing the true SN because the lymphatic channels are not connected at that point. There is also demonstration of a distant echelon node, which might not contain tumor. The former finding is referred to as a missed SN (MSN) if no perilesional injection was performed; the latter finding is potentially referred to as a false SN (FSN) or a false-negative node (FNN) (5,25). (e) Anterior midstudy image of the left side of the chest, obtained after perilesional and areolar-cutaneous junction injections, shows activity tracking to the same sentinel and echelon nodes along different pathways. Such an "all roads lead to Rome" pattern is seen most of the time with combination injections. (Fig 5a reprinted, with permission, from reference 19; Fig 5d reprinted, with permission, from reference 5.)

View larger version (21K): [in a new window]   Figure 5b.  Potential connections between lymph nodes and lymphatic channels. (a) Drawing of a lymph node shows serial connections to germinal centers and alternate connections that mostly bypass the germinal centers, running through the node or on the surface without connecting (19). (b) Diagrams show a serial connection (which is most common) and an alternate parallel connection, which has reduced flow compared with that of serial connections. (c) Anterior midstudy image of the left side of the chest, obtained after perilesional and skin injections, shows a bright focus and a fainter focus (arrow), which appeared simultaneously. The latter is closer to the tumor in the breast and potentially represents a node fed through a side parallel connection or a node that is only partially visualized due to replacement by metastases. Because the fainter focus intensified over time and persisted on delayed views, ectasia was less likely. (d) Diagrams show possible connections between a tumor and lymph nodes. PL = perilesional injection site. 1, Perilesional injection demonstrates the SN and a more distant axillary echelon node. 2, Surface injection leads to augmentation of the nodes seen after the perilesional injection. EN = echelon node. 3, Surface injection leads to augmentation of the nodes seen after the perilesional injection, with additional foci appearing proximally, upstream from the originally delineated SNs. This appearance could represent pooling of activity in a dilated area, that is, a pseudo-SN (PSN) or a reverse echelon node (REN). A reverse echelon node is an upstream node that is distinct from the primary SN seen after the initial perilesional injection and that receives activity only from the surface injection. It is usually closer to the tumor and technically is not part of the tumor drainage, since it is not seen with the original perilesional injection but only after the surface injection. The more distant true SN is almost always augmented by surface injections, since it is downstream along the lymphatic chain. 4, Surface injection leads to activity bypassing the true SN because the lymphatic channels are not connected at that point. There is also demonstration of a distant echelon node, which might not contain tumor. The former finding is referred to as a missed SN (MSN) if no perilesional injection was performed; the latter finding is potentially referred to as a false SN (FSN) or a false-negative node (FNN) (5,25). (e) Anterior midstudy image of the left side of the chest, obtained after perilesional and areolar-cutaneous junction injections, shows activity tracking to the same sentinel and echelon nodes along different pathways. Such an "all roads lead to Rome" pattern is seen most of the time with combination injections. (Fig 5a reprinted, with permission, from reference 19; Fig 5d reprinted, with permission, from reference 5.)

View larger version (164K): [in a new window]   Figure 5c.  Potential connections between lymph nodes and lymphatic channels. (a) Drawing of a lymph node shows serial connections to germinal centers and alternate connections that mostly bypass the germinal centers, running through the node or on the surface without connecting (19). (b) Diagrams show a serial connection (which is most common) and an alternate parallel connection, which has reduced flow compared with that of serial connections. (c) Anterior midstudy image of the left side of the chest, obtained after perilesional and skin injections, shows a bright focus and a fainter focus (arrow), which appeared simultaneously. The latter is closer to the tumor in the breast and potentially represents a node fed through a side parallel connection or a node that is only partially visualized due to replacement by metastases. Because the fainter focus intensified over time and persisted on delayed views, ectasia was less likely. (d) Diagrams show possible connections between a tumor and lymph nodes. PL = perilesional injection site. 1, Perilesional injection demonstrates the SN and a more distant axillary echelon node. 2, Surface injection leads to augmentation of the nodes seen after the perilesional injection. EN = echelon node. 3, Surface injection leads to augmentation of the nodes seen after the perilesional injection, with additional foci appearing proximally, upstream from the originally delineated SNs. This appearance could represent pooling of activity in a dilated area, that is, a pseudo-SN (PSN) or a reverse echelon node (REN). A reverse echelon node is an upstream node that is distinct from the primary SN seen after the initial perilesional injection and that receives activity only from the surface injection. It is usually closer to the tumor and technically is not part of the tumor drainage, since it is not seen with the original perilesional injection but only after the surface injection. The more distant true SN is almost always augmented by surface injections, since it is downstream along the lymphatic chain. 4, Surface injection leads to activity bypassing the true SN because the lymphatic channels are not connected at that point. There is also demonstration of a distant echelon node, which might not contain tumor. The former finding is referred to as a missed SN (MSN) if no perilesional injection was performed; the latter finding is potentially referred to as a false SN (FSN) or a false-negative node (FNN) (5,25). (e) Anterior midstudy image of the left side of the chest, obtained after perilesional and areolar-cutaneous junction injections, shows activity tracking to the same sentinel and echelon nodes along different pathways. Such an "all roads lead to Rome" pattern is seen most of the time with combination injections. (Fig 5a reprinted, with permission, from reference 19; Fig 5d reprinted, with permission, from reference 5.)

View larger version (23K): [in a new window]   Figure 5d.  Potential connections between lymph nodes and lymphatic channels. (a) Drawing of a lymph node shows serial connections to germinal centers and alternate connections that mostly bypass the germinal centers, running through the node or on the surface without connecting (19). (b) Diagrams show a serial connection (which is most common) and an alternate parallel connection, which has reduced flow compared with that of serial connections. (c) Anterior midstudy image of the left side of the chest, obtained after perilesional and skin injections, shows a bright focus and a fainter focus (arrow), which appeared simultaneously. The latter is closer to the tumor in the breast and potentially represents a node fed through a side parallel connection or a node that is only partially visualized due to replacement by metastases. Because the fainter focus intensified over time and persisted on delayed views, ectasia was less likely. (d) Diagrams show possible connections between a tumor and lymph nodes. PL = perilesional injection site. 1, Perilesional injection demonstrates the SN and a more distant axillary echelon node. 2, Surface injection leads to augmentation of the nodes seen after the perilesional injection. EN = echelon node. 3, Surface injection leads to augmentation of the nodes seen after the perilesional injection, with additional foci appearing proximally, upstream from the originally delineated SNs. This appearance could represent pooling of activity in a dilated area, that is, a pseudo-SN (PSN) or a reverse echelon node (REN). A reverse echelon node is an upstream node that is distinct from the primary SN seen after the initial perilesional injection and that receives activity only from the surface injection. It is usually closer to the tumor and technically is not part of the tumor drainage, since it is not seen with the original perilesional injection but only after the surface injection. The more distant true SN is almost always augmented by surface injections, since it is downstream along the lymphatic chain. 4, Surface injection leads to activity bypassing the true SN because the lymphatic channels are not connected at that point. There is also demonstration of a distant echelon node, which might not contain tumor. The former finding is referred to as a missed SN (MSN) if no perilesional injection was performed; the latter finding is potentially referred to as a false SN (FSN) or a false-negative node (FNN) (5,25). (e) Anterior midstudy image of the left side of the chest, obtained after perilesional and areolar-cutaneous junction injections, shows activity tracking to the same sentinel and echelon nodes along different pathways. Such an "all roads lead to Rome" pattern is seen most of the time with combination injections. (Fig 5a reprinted, with permission, from reference 19; Fig 5d reprinted, with permission, from reference 5.)

View larger version (84K): [in a new window]   Figure 5e.  Potential connections between lymph nodes and lymphatic channels. (a) Drawing of a lymph node shows serial connections to germinal centers and alternate connections that mostly bypass the germinal centers, running through the node or on the surface without connecting (19). (b) Diagrams show a serial connection (which is most common) and an alternate parallel connection, which has reduced flow compared with that of serial connections. (c) Anterior midstudy image of the left side of the chest, obtained after perilesional and skin injections, shows a bright focus and a fainter focus (arrow), which appeared simultaneously. The latter is closer to the tumor in the breast and potentially represents a node fed through a side parallel connection or a node that is only partially visualized due to replacement by metastases. Because the fainter focus intensified over time and persisted on delayed views, ectasia was less likely. (d) Diagrams show possible connections between a tumor and lymph nodes. PL = perilesional injection site. 1, Perilesional injection demonstrates the SN and a more distant axillary echelon node. 2, Surface injection leads to augmentation of the nodes seen after the perilesional injection. EN = echelon node. 3, Surface injection leads to augmentation of the nodes seen after the perilesional injection, with additional foci appearing proximally, upstream from the originally delineated SNs. This appearance could represent pooling of activity in a dilated area, that is, a pseudo-SN (PSN) or a reverse echelon node (REN). A reverse echelon node is an upstream node that is distinct from the primary SN seen after the initial perilesional injection and that receives activity only from the surface injection. It is usually closer to the tumor and technically is not part of the tumor drainage, since it is not seen with the original perilesional injection but only after the surface injection. The more distant true SN is almost always augmented by surface injections, since it is downstream along the lymphatic chain. 4, Surface injection leads to activity bypassing the true SN because the lymphatic channels are not connected at that point. There is also demonstration of a distant echelon node, which might not contain tumor. The former finding is referred to as a missed SN (MSN) if no perilesional injection was performed; the latter finding is potentially referred to as a false SN (FSN) or a false-negative node (FNN) (5,25). (e) Anterior midstudy image of the left side of the chest, obtained after perilesional and areolar-cutaneous junction injections, shows activity tracking to the same sentinel and echelon nodes along different pathways. Such an "all roads lead to Rome" pattern is seen most of the time with combination injections. (Fig 5a reprinted, with permission, from reference 19; Fig 5d reprinted, with permission, from reference 5.)

View larger version (73K): [in a new window]   Figure 6a.  (a) Anterior images obtained with dual energy channels. The image obtained with the lower channel shows little useful information, but the image obtained with the higher channel shows a partly hidden SN. (b) Lateral images of another patient obtained with dual energy channels. The image obtained with the lower channel shows shallow angle scatter from the arm, but the image obtained with the higher channel shows an SN (arrow), which is no longer obscured by the scatter.

View larger version (78K): [in a new window]   Figure 6b.  (a) Anterior images obtained with dual energy channels. The image obtained with the lower channel shows little useful information, but the image obtained with the higher channel shows a partly hidden SN. (b) Lateral images of another patient obtained with dual energy channels. The image obtained with the lower channel shows shallow angle scatter from the arm, but the image obtained with the higher channel shows an SN (arrow), which is no longer obscured by the scatter.

View larger version (109K): [in a new window]   Figure 7a.  Early (a) and late (b) anterior images of the left side of the chest show an SN (arrow) and the injection site (IS). There is also an "inverted J"-type pattern, which represents a lymphatic channel that courses above the SN before turning inferiorly, deep to the SN. Potential causes of this pattern include pathways in the skin plexus that follow a large, cranially bulging breast before connecting to the deeper plexus of axillary lymphatics (dashed curve in b). Other possible causes include upward "tenting" of lymphatics due to a raised arm position, thus producing an inflection point, or alternate pathways secondary to complete replacement of nodes by the tumor. (Reprinted, with permission, from reference 5.)

View larger version (147K): [in a new window]   Figure 7b.  Early (a) and late (b) anterior images of the left side of the chest show an SN (arrow) and the injection site (IS). There is also an "inverted J"-type pattern, which represents a lymphatic channel that courses above the SN before turning inferiorly, deep to the SN. Potential causes of this pattern include pathways in the skin plexus that follow a large, cranially bulging breast before connecting to the deeper plexus of axillary lymphatics (dashed curve in b). Other possible causes include upward "tenting" of lymphatics due to a raised arm position, thus producing an inflection point, or alternate pathways secondary to complete replacement of nodes by the tumor. (Reprinted, with permission, from reference 5.)

View larger version (143K): [in a new window]   Figure 8.  Anterior midstudy image of the right side of the chest shows the injection site (IS) and an SN. There is also a focus of activity in the breast (arrow), which was excised. Histologic analysis demonstrated that the focus was a dilated lymphatic channel. No node was found. Such foci are known as pseudo-SNs. They usually disappear on delayed images and do not intensify over time.

View larger version (110K): [in a new window]   Figure 9a.  (a) Anterior early image of the left side of the chest shows a focus of activity (arrow). This is not an SN but a lymphatic channel seen "end on," which can be erroneously interpreted as an SN because of the end-on effect. (b-d) Multiangle sequence of images presented from anterior (b) to lateral (d) shows the end-on effect. The lymphatic channel appears as an arch leading from the injection site to an SN, which is mostly hidden on the anterior images (a and b) by the injection site. D = dermal injection site, P = perilesional injection site. (Reprinted, with permission, from reference 5.)

View larger version (75K): [in a new window]   Figure 9b.  (a) Anterior early image of the left side of the chest shows a focus of activity (arrow). This is not an SN but a lymphatic channel seen "end on," which can be erroneously interpreted as an SN because of the end-on effect. (b-d) Multiangle sequence of images presented from anterior (b) to lateral (d) shows the end-on effect. The lymphatic channel appears as an arch leading from the injection site to an SN, which is mostly hidden on the anterior images (a and b) by the injection site. D = dermal injection site, P = perilesional injection site. (Reprinted, with permission, from reference 5.)

View larger version (67K): [in a new window]   Figure 9c.  (a) Anterior early image of the left side of the chest shows a focus of activity (arrow). This is not an SN but a lymphatic channel seen "end on," which can be erroneously interpreted as an SN because of the end-on effect. (b-d) Multiangle sequence of images presented from anterior (b) to lateral (d) shows the end-on effect. The lymphatic channel appears as an arch leading from the injection site to an SN, which is mostly hidden on the anterior images (a and b) by the injection site. D = dermal injection site, P = perilesional injection site. (Reprinted, with permission, from reference 5.)

View larger version (82K): [in a new window]   Figure 9d.  (a) Anterior early image of the left side of the chest shows a focus of activity (arrow). This is not an SN but a lymphatic channel seen "end on," which can be erroneously interpreted as an SN because of the end-on effect. (b-d) Multiangle sequence of images presented from anterior (b) to lateral (d) shows the end-on effect. The lymphatic channel appears as an arch leading from the injection site to an SN, which is mostly hidden on the anterior images (a and b) by the injection site. D = dermal injection site, P = perilesional injection site. (Reprinted, with permission, from reference 5.)

View larger version (145K): [in a new window]   Figure 10.  Anterior end-of-study image of the right side of the chest shows a prominent SN (arrow) above the injection site. The activity in the salivary gland, thyroid gland, and stomach is due to free pertechnetate. The free pertechnetate could be secondary to faulty synthesis of the radiocolloid, radiolytic decomposition of the radiocolloid over time, or oxidation. Sources of free pertechnetate also include high "carrier" levels of Tc-99 in the elution and inadequate reaction conditions (ie, incorrect mixing order, low heating temperature, or short heating time). Surgeons must be alerted to a slightly increased background level and organ activity. However, these findings will not hamper harvesting of SNs.

View larger version (114K): [in a new window]   Figure 11a.  Rare leakage patterns. (a) Lateral end-of-study image of the right side of the chest shows leakage of the radiotracer along a localization wire with pooling at the wire tip (arrow). (b) Anterior end-of-study image of the right side of the chest, obtained in another patient after perilesional injection 4 cm from the tip of the nipple, shows activity in a lactiferous channel leading to the nipple tip (arrow). After the injection, some of the radiotracer had squirted out of the nipple. IM = internal mammary SNs.

View larger version (193K): [in a new window]   Figure 11b.  Rare leakage patterns. (a) Lateral end-of-study image of the right side of the chest shows leakage of the radiotracer along a localization wire with pooling at the wire tip (arrow). (b) Anterior end-of-study image of the right side of the chest, obtained in another patient after perilesional injection 4 cm from the tip of the nipple, shows activity in a lactiferous channel leading to the nipple tip (arrow). After the injection, some of the radiotracer had squirted out of the nipple. IM = internal mammary SNs.

View larger version (101K): [in a new window]   Figure 12a.  (a) Anterior end-of-study images show bilateral lesions and a small amount of free pertechnetate (in the thyroid gland, salivary glands, and stomach), which is useful as a positional reference. On each side, the distance from the perilesional injection site to the node varies with the position of the patient, increasing when the patient stands and when the arms are lowered. Delineation of axillary nodes increases as overlap decreases when the patient stands and when the arms are lowered. In addition, the breasts move medially when the patient stands. (b) Anterior images show a marked shift in the positions of the combined perilesional-areolar injection site and the axillary nodes (vertical dashed line) when the patient is standing with the arm out versus supine with the arm up. However, there is no change in the position of an internal mammary node (horizontal dashed line). When the patient is supine with the arm up, axillary nodes tend to bunch up, the distance between the injection site and the nodes decreases, and the breast moves laterally.

View larger version (139K): [in a new window]   Figure 12b.  (a) Anterior end-of-study images show bilateral lesions and a small amount of free pertechnetate (in the thyroid gland, salivary glands, and stomach), which is useful as a positional reference. On each side, the distance from the perilesional injection site to the node varies with the position of the patient, increasing when the patient stands and when the arms are lowered. Delineation of axillary nodes increases as overlap decreases when the patient stands and when the arms are lowered. In addition, the breasts move medially when the patient stands. (b) Anterior images show a marked shift in the positions of the combined perilesional-areolar injection site and the axillary nodes (vertical dashed line) when the patient is standing with the arm out versus supine with the arm up. However, there is no change in the position of an internal mammary node (horizontal dashed line). When the patient is supine with the arm up, axillary nodes tend to bunch up, the distance between the injection site and the nodes decreases, and the breast moves laterally.

View larger version (112K): [in a new window]   Figure 13a.  Obscuration of an SN due to injection site activity and the attenuating effects of breast tissues. (a) Lateral end-of-study image of the right side of the chest shows an SN behind the inferior portion of the injection site. (b) Anterior images show that the node (arrows) is mostly hidden due to overlap with the injection site and attenuation effects. (c) Images obtained with the breast displaced cranially and medially show that the injection site overlap has been resolved and some of the attenuation has been eliminated (arrows). Breast displacement will alter the positions of surface markings when the breast is released and must be taken into account.

View larger version (101K): [in a new window]   Figure 13b.  Obscuration of an SN due to injection site activity and the attenuating effects of breast tissues. (a) Lateral end-of-study image of the right side of the chest shows an SN behind the inferior portion of the injection site. (b) Anterior images show that the node (arrows) is mostly hidden due to overlap with the injection site and attenuation effects. (c) Images obtained with the breast displaced cranially and medially show that the injection site overlap has been resolved and some of the attenuation has been eliminated (arrows). Breast displacement will alter the positions of surface markings when the breast is released and must be taken into account.

View larger version (102K): [in a new window]   Figure 13c.  Obscuration of an SN due to injection site activity and the attenuating effects of breast tissues. (a) Lateral end-of-study image of the right side of the chest shows an SN behind the inferior portion of the injection site. (b) Anterior images show that the node (arrows) is mostly hidden due to overlap with the injection site and attenuation effects. (c) Images obtained with the breast displaced cranially and medially show that the injection site overlap has been resolved and some of the attenuation has been eliminated (arrows). Breast displacement will alter the positions of surface markings when the breast is released and must be taken into account.

View larger version (125K): [in a new window]   Figure 14.  Anterior end-of-study image of the chest shows bilateral lesions and injection sites (IS). In the right breast, nodes appear in a chain of decreasing intensity (1, 2, and 3) as the radiotracer is successively filtered by macrophages. The first node is the more important SN; the more distant nodes are the echelon nodes. This pattern can occur with any injection method and is often seen with dermal or areolar-cutaneous junction injections. Clavicular or supraclavicular SNs (SC SN) are seen medially on the right; their appearance is possibly due to activity in a distal branching lymphatic channel. In the left breast, two nodes with nearly equal activity are seen. In the rare case of bilateral lesions, use of 90° lateral images should be avoided when the technique is just being learned, as "shine through" of activity in the opposing axillary nodes and breast could complicate image interpretation. Acquisition of 45° oblique images will not produce any significant overlap, and the preferred surgical position (with the arm perpendicular, not raised) can then be used. If such altered image acquisition and body marking are used, the surgeons must be made aware of the altered triangulation pattern needed.

View larger version (25K): [in a new window]   Figure 15.  Method of accurately marking the patient’s body by using triangulation. The patient is imaged, and the position of the SN is noted on the monitor screen. An observer, who remains in a fixed position in front of the monitor to avoid parallax error, attaches a small piece of tape (or makes a mark with a nonpermanent marker) over the position of the SN on the monitor screen. A physician, who is holding a radioactive point source in one hand and a color-coded permanent marker in the other, moves the point source into the field of view. The observer, who is sitting or standing in front of the monitor without having moved, then guides the physician (with constant refreshing of the persistent screen image) as the point source is moved along the patient’s body until it is positioned under the reference point on the monitor screen (the tape or nonpermanent mark placed there earlier), at which time the patient’s body is marked by the physician with the color-coded permanent marker. This process is repeated in a different projection, usually 90° or 45°. Keep in mind that displacement of the breast or arm will alter the relationships of the surface markings to the SN (5,11).

View larger version (105K): [in a new window]   Figure 16a.  (a-c) Lateral images show three methods of outlining the patient’s body. (a) In the recommended and probably most common method, a Co-57 (122-keV) transmission sheet source is placed behind the patient, with the patient (the attenuating mass) between the sheet source and the head of the camera. (b) Radioactive material in a syringe is used to paint a background behind the patient by using an up-and-down motion. It is more difficult to achieve a uniform result with this method, and radiation exposure is an issue. (c) In the edge outlining method, a simple point source of activity (Tc-99m) is used to trace the edges of the patient’s body. However, the inferior surface is not easily traced due to the imaging table. As an alternative, a flexible "tube" line source can be taped to the patient and used as a marker, which will produce similar results. (d) Photograph shows a patient positioned between a Co-57 sheet source and the head of the camera (the method used in a).

View larger version (104K): [in a new window]   Figure 16b.  (a-c) Lateral images show three methods of outlining the patient’s body. (a) In the recommended and probably most common method, a Co-57 (122-keV) transmission sheet source is placed behind the patient, with the patient (the attenuating mass) between the sheet source and the head of the camera. (b) Radioactive material in a syringe is used to paint a background behind the patient by using an up-and-down motion. It is more difficult to achieve a uniform result with this method, and radiation exposure is an issue. (c) In the edge outlining method, a simple point source of activity (Tc-99m) is used to trace the edges of the patient’s body. However, the inferior surface is not easily traced due to the imaging table. As an alternative, a flexible "tube" line source can be taped to the patient and used as a marker, which will produce similar results. (d) Photograph shows a patient positioned between a Co-57 sheet source and the head of the camera (the method used in a).

View larger version (81K): [in a new window]   Figure 16c.  (a-c) Lateral images show three methods of outlining the patient’s body. (a) In the recommended and probably most common method, a Co-57 (122-keV) transmission sheet source is placed behind the patient, with the patient (the attenuating mass) between the sheet source and the head of the camera. (b) Radioactive material in a syringe is used to paint a background behind the patient by using an up-and-down motion. It is more difficult to achieve a uniform result with this method, and radiation exposure is an issue. (c) In the edge outlining method, a simple point source of activity (Tc-99m) is used to trace the edges of the patient’s body. However, the inferior surface is not easily traced due to the imaging table. As an alternative, a flexible "tube" line source can be taped to the patient and used as a marker, which will produce similar results. (d) Photograph shows a patient positioned between a Co-57 sheet source and the head of the camera (the method used in a).

View larger version (134K): [in a new window]   Figure 16d.  (a-c) Lateral images show three methods of outlining the patient’s body. (a) In the recommended and probably most common method, a Co-57 (122-keV) transmission sheet source is placed behind the patient, with the patient (the attenuating mass) between the sheet source and the head of the camera. (b) Radioactive material in a syringe is used to paint a background behind the patient by using an up-and-down motion. It is more difficult to achieve a uniform result with this method, and radiation exposure is an issue. (c) In the edge outlining method, a simple point source of activity (Tc-99m) is used to trace the edges of the patient’s body. However, the inferior surface is not easily traced due to the imaging table. As an alternative, a flexible "tube" line source can be taped to the patient and used as a marker, which will produce similar results. (d) Photograph shows a patient positioned between a Co-57 sheet source and the head of the camera (the method used in a).

View larger version (121K): [in a new window]   Figure 17a.  Use of the lymphoboost technique in the left breast. (a) Anterior image obtained before lymphoboost (LB) injection shows the sites of combined perilesional (PL) and intradermal (ID) injections and an SN. (b) Anterior end-of-study image, obtained with Co-57 backlighting after lymphoboost injection, shows marked augmentation of the SN, as well as additional second- and third-tier echelon nodes of lesser intensity. The diffusion field does not extend significantly toward the axilla. (c-f) Sequence of dynamic lateral images, obtained over 6 minutes just before (c), during (d, e), and after (f) lymphoboost injection, show augmentation of activity in the SN (* in f) even before the syringe is empty. A prominent lymphatic channel leading to the node is seen.

View larger version (133K): [in a new window]   Figure 17b.  Use of the lymphoboost technique in the left breast. (a) Anterior image obtained before lymphoboost (LB) injection shows the sites of combined perilesional (PL) and intradermal (ID) injections and an SN. (b) Anterior end-of-study image, obtained with Co-57 backlighting after lymphoboost injection, shows marked augmentation of the SN, as well as additional second- and third-tier echelon nodes of lesser intensity. The diffusion field does not extend significantly toward the axilla. (c-f) Sequence of dynamic lateral images, obtained over 6 minutes just before (c), during (d, e), and after (f) lymphoboost injection, show augmentation of activity in the SN (* in f) even before the syringe is empty. A prominent lymphatic channel leading to the node is seen.

View larger version (113K): [in a new window]   Figure 17c.  Use of the lymphoboost technique in the left breast. (a) Anterior image obtained before lymphoboost (LB) injection shows the sites of combined perilesional (PL) and intradermal (ID) injections and an SN. (b) Anterior end-of-study image, obtained with Co-57 backlighting after lymphoboost injection, shows marked augmentation of the SN, as well as additional second- and third-tier echelon nodes of lesser intensity. The diffusion field does not extend significantly toward the axilla. (c-f) Sequence of dynamic lateral images, obtained over 6 minutes just before (c), during (d, e), and after (f) lymphoboost injection, show augmentation of activity in the SN (* in f) even before the syringe is empty. A prominent lymphatic channel leading to the node is seen.

View larger version (114K): [in a new window]   Figure 17d.  Use of the lymphoboost technique in the left breast. (a) Anterior image obtained before lymphoboost (LB) injection shows the sites of combined perilesional (PL) and intradermal (ID) injections and an SN. (b) Anterior end-of-study image, obtained with Co-57 backlighting after lymphoboost injection, shows marked augmentation of the SN, as well as additional second- and third-tier echelon nodes of lesser intensity. The diffusion field does not extend significantly toward the axilla. (c-f) Sequence of dynamic lateral images, obtained over 6 minutes just before (c), during (d, e), and after (f) lymphoboost injection, show augmentation of activity in the SN (* in f) even before the syringe is empty. A prominent lymphatic channel leading to the node is seen.

View larger version (115K): [in a new window]   Figure 17e.  Use of the lymphoboost technique in the left breast. (a) Anterior image obtained before lymphoboost (LB) injection shows the sites of combined perilesional (PL) and intradermal (ID) injections and an SN. (b) Anterior end-of-study image, obtained with Co-57 backlighting after lymphoboost injection, shows marked augmentation of the SN, as well as additional second- and third-tier echelon nodes of lesser intensity. The diffusion field does not extend significantly toward the axilla. (c-f) Sequence of dynamic lateral images, obtained over 6 minutes just before (c), during (d, e), and after (f) lymphoboost injection, show augmentation of activity in the SN (* in f) even before the syringe is empty. A prominent lymphatic channel leading to the node is seen.

View larger version (111K): [in a new window]   Figure 17f.  Use of the lymphoboost technique in the left breast. (a) Anterior image obtained before lymphoboost (LB) injection shows the sites of combined perilesional (PL) and intradermal (ID) injections and an SN. (b) Anterior end-of-study image, obtained with Co-57 backlighting after lymphoboost injection, shows marked augmentation of the SN, as well as additional second- and third-tier echelon nodes of lesser intensity. The diffusion field does not extend significantly toward the axilla. (c-f) Sequence of dynamic lateral images, obtained over 6 minutes just before (c), during (d, e), and after (f) lymphoboost injection, show augmentation of activity in the SN (* in f) even before the syringe is empty. A prominent lymphatic channel leading to the node is seen.