Article Figures & Data
Figures
- Fig 1.
Visualization of the 18-gauge needles by using a 0.2-T interventional magnet, a two-dimensional (2D) fast low-angle shot (FLASH) sequence (TR/TE/NEX = 341/12/1), and a melon as the test object. Magnetic-susceptibility artifact from the needles, which are of identical size, increased with their angle from the Z axis. Needle in alignment with the Z axis of the magnet (vertical) is barely visible (white arrow), but needles at an angle of ≥30° are well demonstrated. Needle perpendicular to the Z axis shows the most pronounced susceptibility artifact, with exaggeration of its actual diameter (black arrow).
- Fig 2.
Schematic of IPDT. Primary laser beam (652-nm wavelength) is split into four treatment fibers, which allow for simultaneous delivery of light at four points. Optic fibers are fed through 18-gauge needles placed under MR imaging guidance; they protrude slightly beyond the needle tips. Energy deposition of 20 J via these fibers illuminates an area of about 10 mm in radius, in which the photosensitizer is activated. Deepest parts of the tumor are illuminated first (red spheres). Subsequent incremental withdrawal of the laser fibers and needles with further energy deposition produces overlapping spheres of illumination (pink), leading to activation of photosensitizer in the most of the tumor.
- Fig 3.
IPDT of an SCC arising from the external auditory meatus.
A, Axial enhanced T1-weighted SE image (TR/TE/NEX = 893/15/2) obtained 3 days before IPDT shows a strongly and relatively homogenously enhancing tumor.
B–D, Axial (B), oblique sagittal (C), and oblique coronal (D) 2D FLASH images (TR/TE/NEX = 341/12/1) obtained during treatment show an approximately equal distribution of four 18-gauge needles in the tumor. Rotation of the patient’s head, as shown in A, avoids alignment of the needles with the Z axis and increases their visibility.
E, Axial enhanced T1-weighted SE image obtained 6 days after treatment shows an extensive nonenhancing area of tumor necrosis. Vertical arrow shows the needle trajectory during IPDT. Horizontal arrows indicates the diameter of the area of necrosis perpendicular to the needle trajectory.
- Fig 4.
Sagittal 2D FLASH images obtained during IPDT of a hemangiopericytoma at the base of the tongue.
A, Initial entry angle of the 18-gauge needles, based on palpation of the tumor, had been misjudged, and the needles came to lie close behind the mandible (arrow). Needle artifact is large because of the almost-90° angle with the Z axis.
B, Imaging in the plane of the needle shafts allowed for easy correction of the entry angle and redirection of the needles toward the center of the tumor.
- Fig 5.
IPDT of a branchial duct carcinoma.
A, 2D FLASH image shows the position of the needles in the tumor before insertion of the laser fibers. Middle needle points toward the left internal carotid artery (arrow), which is hyperintense because of inflow effects. Distance of at least 15 mm from the vessel must be maintained to avoid carotid blowout.
B, Coronal enhanced T1-weighted SE image at 5 days after treatment shows areas of necrosis in the tumor and preservation of the internal carotid artery (arrow), which is hypointense because of flow void.
- Fig 6.
IPDT of a recurrent adenoid cystic carcinoma of the right maxillary antrum.
A, Coronal enhanced T1-weighted SE image before treatment shows the extensive, enhancing tumor invading neighboring structures, including the extraconal space of the right orbit (white arrow) and the floor of anterior cranial fossa (black arrow).
B, Coronal oblique 2D FLASH image shows the position of the 18-gauge needles in the tumor mass.
C, Coronal enhanced T1-weighted SE image at 5 days after treatment shows markedly reduced tumoral enhancement with areas of necrosis.
D, Coronal enhanced T1-weighted SE image at 6 weeks after treatment shows that a substantial portion of the necrotic tumor has sloughed off.
Tables
Clinical data
Patient/Age (y) Diagnosis* Indication for PDT Tumor Volume (mL) Treatment of Spheres (n) Repeat PDT Survival after First PDT (wk)† 1/53 Neck node metastasis of tongue SCC Brachial plexus pain 10 4 No 72 2/60 SCC, base of tongue Pain 33 8 No 72 3/76 Adenoid cystic carcinoma, maxillary antrum Nasal obstruction, epistaxis 65 16 At 27 and 51 wk 83 4/45 SCC floor of mouth Aphonia 24 12 No 24 5/39 Spindle cell carcinoma of cheek‡ Pain, debulking 11 6 At 15 wk 60 6/51 SCC of branchial cyst Swelling, pain 37 12 At 33 and 57 wk 72 7/69 SCC neck node metastasis Dysphagia 81 16 No 12 8/54 Hemangiopericytoma submandibular area‡ Debulking, dysphagia 106 32 No 16 9/42 Adenoid cystic carcinoma, parotid Pain, debulking 13 8 No Alive at 158 wk 10/50 SCC, tongue Debulking 58 12 No 1§ 11/54 SCC, tonsil Debulking 122 20 No 18 12/68 SCC, tongue Pain 41 7 No 38 13/61 SCC, external ear Debulking 65 16 No 66 14/39 Neuroectodermal tumor, face and neck‡ Debulking 177 32 No 8 * SCC = squamous cell carcinoma.
† Although survival in patients with adenoid cystic carcinoma can be prolonged, expected survival for those with recurrent squamous cell carcinoma is about 2 months.
‡ Survival of rarer tumors is difficult to predict.
§ Died from accidental morphine overdose.
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