Apparatus for Combined Localization and Dosimetry in Image Guided Radiation Therapy of the Head and Neck

Abstract

Apparatus for improving image guidance in radiation therapy applications are described. In one aspect, a patient support with integrated radiopaque markers is described. In another aspect, a bite block with integrated sensors, radiopaque markers, or both, is described. The integrated sensors may include a radiation detector, a pH sensor, or both. Radiation detectors that may be used include a dosimeter. As an example, the dosimeter may include a film dosimeter, an ion chamber dosimeter, a diode dosimeter, or other suitable dosimeters and combinations thereof.

Claims

1. A bite block, comprising: a mouthpiece having formed therein a channel that is shaped to be retained by a patient's teeth when positioned in an oral cavity of the patient; a port extending through the mouthpiece from a forward surface of the mouthpiece to a rear surface of the mouthpiece; a tongue depressor; a sheath extending from a proximal end at the rear surface of the mouthpiece to a distal end at the tongue depressor to couple the mouthpiece to the tongue depressor; at least one radiopaque marker coupled to the tongue depressor; and a pH sensor coupled to the tongue depressor.

2. The bite block as recited in claim 1, wherein the sheath is a telescoping sheath that is operable to be adjusted to change a depth of the tongue depressor relative to the rear surface of the mouthpiece.

3. The bite block as recited in claim 2, further comprising a distance scale coupled to the telescoping sheath, wherein the distance scale indicates the depth of the tongue depressor as the telescoping sheath is adjusted.

4. The bite block as recited in claim 1, wherein the tongue depressor comprises a housing having an internal cavity and the pH sensor is arranged within the internal cavity.

5. The bite block as recited in claim 1, further comprising at least one dosimeter coupled to at least one of the sheath or the tongue depressor.

6. The bite block as recited in claim 5, wherein the tongue depressor comprises a housing having an internal cavity and the at least one dosimeter is removably arranged in the internal cavity via the sheath.

7. The bite block as recited in claim 5, wherein the at least one dosimeter comprises at least one of a diode dosimeter, an ion chamber dosimeter, or a film dosimeter.

8. The bite block as recited in claim 7, further comprising at least one slit formed in the tongue depressor, and wherein the at least one dosimeter comprises a film dosimeter that is received in the slit.

9. The bite block as recited in claim 5, wherein the at least one dosimeter is arranged in the sheath.

10. The bite block as recited in claim 1, further comprising at least one additional radiopaque marker coupled to at least one of the mouthpiece or the sheath.

11. The bite block as recited in claim 1, wherein the at least one radiopaque marker comprises a plurality of radiopaque markers arranged in a pattern that provides for localization of the tongue depressor in an x-ray image that depicts the tongue depressor.

12. The bite block as recited in claim 1, wherein the mouthpiece is composed of a flexible material.

13. The bite block as recited in claim 12, wherein the flexible material is a flexible plastic.

14. The bite block as recited in claim 1, further comprising a plurality of ridges formed in the channel in order to provide a surface for receiving a putty.

15. The bite block as recited in claim 1, wherein the tongue depressor is coated with a flavored coating.

16. The bite block as recited in claim 1, further comprising a port formed in the tongue depressor and extending to an exterior surface of the tongue depressor to provide for fluid communication through the exterior surface of the tongue depressor.

17. The bite block as recited in claim 16, wherein the port fluidly couples the sheath to the exterior surface of the tongue depressor, such that a fluid provided to the sheath can flow through the exterior surface of the tongue depressor into the oral cavity of the patient.

18. The bite block as recited in claim 16, wherein the tongue depressor comprises a housing having an internal cavity, and wherein the port formed in the tongue depressor extends from the internal cavity to the exterior surface in order to provide fluid communication between the internal cavity and the exterior surface of the tongue depressor.

19. The bite block as recited in claim 1, further comprising: an attachment guide formed at the proximal end of the sheath and extending from the rear surface of the mouthpiece to the forward surface of the mouthpiece, the attachment guide having a threaded portion that extends beyond the forward surface of the mouthpiece; and a nut configured to be received by the threaded portion of the attachment guide and to secure the mouthpiece to a face mask that is arranged between the nut and the mouthpiece.

20. The bite block as recited in claim 1, wherein the pH sensor comprises pH ion selective field effect transistors.

21. The bite block as recited in claim 1, wherein the at least one radiopaque marker comprises at least one of a radiopaque sphere, bead, or wire.

22. A patient support, comprising: a cushion; and a radiopaque assembly coupled to an exterior surface of the cushion, wherein the radiopaque assembly comprises: a radiolucent plate; and a plurality of radiopaque indicia arranged on the radiolucent plate in an arrangement that indicates spatial location information.

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Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] FIG. 1 is an example of a bite block with integrated radiopaque markers, dosimeter, and pH sensor, according to some embodiments of the present disclosure.

[0012] FIG. 2 is another view of the bite block of FIG. 1.

[0013] FIG. 3 is an example of some of the components of the bite block of FIG. 1, including those for securing the bite block assembly to a face mask, such as a patient immobilization face mask.

[0014] FIG. 4 shows an example of the bite block of FIG. 1 being secured to a patient immobilization face mask.

[0015] FIG. 5 is an example of a patient support with integrated radiopaque markers for repeatedly and reliably aligning the patient support during a radiation treatment.

[0016] FIG. 6 is an example of a radiopaque marker assembly for use with the patient support shown in FIG. 5.

[0017] FIG. 7 is a planar x-ray radiograph of bite block and patient support described in the present disclosure. The bite block is shown in the center of the image. Radiopaque markers appear as bright dots in the x-ray radiograph. The head cushion is shown in the lower part of the image. Radiopaque wires appear as bright straight lines of varying lengths.

DETAILED DESCRIPTION

[0018] Described here are apparatus for improving image guidance in radiation therapy applications. In one aspect, the present disclosure describes a patient support with integrated radiopaque markers. The patient support may be in some implementations a patient immobilization support. As one example, the patient immobilization support may be a pillow or other supportive cushion. In another aspect, the present disclosure describes a bite block with integrated sensors, radiopaque markers, or both. In some implementations, the integrated sensors may include a radiation detector, a pH sensor, or both. Radiation detectors that may be used include a dosimeter. As an example, the dosimeter may include a film dosimeter, an ion chamber dosimeter, a diode dosimeter, scintillators, or other suitable dosimeters and combinations thereof.

[0019] Referring now to FIGS. 1 and 2, an example of a bite block 10 having embedded radiopaque markers and sensors is shown. The bite block 10 generally includes a mouthpiece 12 and a tongue depressor 14. One or more radiopaque markers 16 are embedded or otherwise arranged on the bite block 10. The bite block 10 may also include one or more dosimeters 18 for measuring radiation dose, one or more physiological sensors 20 for measuring physiological data, or both.

[0020] As one example, the radiopaque markers 16 may be embedded in or otherwise coupled to the tongue depressor 14. One or more radiopaque markers 16 may also be embedded in or coupled to other components of the bite block 10, including the mouthpiece 12. The radiopaque markers 16 can include radiopaque spheres, beads, dots, wires, or other markers. In general, the radiopaque markers 16 are composed of one or more radiopaque materials, such as suitable metals or metal alloys.

[0021] The mouthpiece 12 is configured to be received in an oral cavity of a patient, and has a channel 22 that is retained by the patient's teeth when the bite block 10 is received in the oral cavity of the patient. The mouthpiece 12 can be composed of a suitable flexible material, such as a molded plastic, foam, or so on, in order to comfortably fit the patient's teeth irrespective of the patient's jaw size. In some embodiments, ridges can be formed in the channel 22. The ridges are shaped to receive a putty, which can further stabilize the teeth position.

[0022] A port 24 is formed in the mouthpiece 12 and extends from a front surface 26 of the mouthpiece 12 to a rear surface 28 of the mouthpiece 12. A sheath 30 extends from the mouthpiece 12 to the tongue depressor 14 and couples the mouthpiece 12 to the tongue depressor 14. In some embodiments, the sheath 30 is a telescoping sheath that is operable to extend the tongue depressor 14 to different depths relative to the mouthpiece 12. This feature allows for a patient specific configuration of the bite block 10.

[0023] The sheath 30 may extend through the port 24 from the rear surface 28 of the mouthpiece 12 to the front surface 26 of the mouthpiece 12. In some embodiments, the sheath 30 generally includes a tubular structure having a lumen that extends from the mouthpiece 12 to the tongue depressor 14. For instance, the lumen may connect the port 24 to an internal cavity formed in the tongue depressor 14. The sheath 30 allows for the insertion of one or more dosimeters 18 to measure radiation dose during treatment, one or more sensors 20 to measure physiological or other data, or combinations thereof.

[0024] The dosimeter 18 may be positioned in the sheath 30 during treatment, or can be provided to an interior cavity formed in the tongue depressor 14 via the sheath 30. As one example, the dosimeter 18 can be an ion chamber dosimeter. As another example, the dosimeter 18 can be a diode dosimeter. As still another example, the dosimeter 18 can be a film dosimeter. In some embodiments, one or more slits can be formed in the tongue depressor 14 to receive a film dosimeter. Such film dosimeters may include Gafchromic film, or other suitable radiochromic film. In still other embodiments, the dosimeter 18 can be a scintillator dosimeter.

[0025] One or more sensors 20 can be embedded in, coupled to, or otherwise provided to the tongue depressor 14. For instance, a sensor 20 can be embedded in the tongue depressor 14, coupled to an exterior surface of the tongue depressor 14, arranged in an interior cavity formed in the tongue depressor 14, or so on. In some embodiments, the sensor 20 can be provided to an interior cavity formed in the tongue depressor 14 by way of the sheath 30. In such instances, the sensor 20 may be a removable sensor 20, such that the sensor 20 can be removed from or placed into the interior cavity of the tongue depressor 14 during treatment or while the patient is otherwise immobilized in preparation for treatment.

[0026] In one embodiment, the sensor 20 is a pH sensor that measures pH data from the oral cavity of the patient. For instance, the pH sensor can monitor the pH of the patient's saliva during treatment and over the course of treatment. In other embodiments, the sensor 20 can measure other physiological data, including other electrochemistry data. As one example, the pH sensor can include pHFET (pH ion selective field effect transistors) as the sensing element. In some implementations, the pH sensor can include a strip of pHFET. The strip may have a thickness on the order of microns. The pH sensor can in some configurations detect or otherwise measure the mobility of molar hydronium and hydroxonium ions. As one example, the pH sensor can be manufactured using nanolithography techniques. In such instances, the pH sensor can be manufactured to include MOSFET circuitry that can encase sensitive electrodes, which can then be integrated within the bite block 10.

[0027] The tongue depressor 14 can in some embodiments be coated with edible flavors. In some configurations, a port 32 can be formed in the tongue depressor 14. For instance, the port 32 can extend from the sheath 30 to an exterior surface of the tongue depressor 14 such that a fluid can be delivered from the sheath 30, through the port 32, and out of the tongue depressor 14. As one non-limiting example, the port 32 can be a medicinal port for releasing pain management medicines or other pharmacological agents during the treatment.

[0028] Referring now to FIG. 3, an exploded view of some components of the bite block 10 is shown. In this example, a face mask attachment guide 34 in conjunction with a nut 36 allows for a stable and reproducible attachment of the bite block 10 to a face mask 38. As noted above, the sheath 30 may be a telescoping sheath. In these instances, a distance scale 40 can be provided on an exterior surface of the sheath 30 to provide a recordable and reproducible tongue depressor 14 insertion. The face mask attachment guide 34 and the sheath 30 allow for the insertion of a dosimeter 18 (e.g., a diode dosimeter) into the tongue depressor 14. The dosimeter 18 can be held in place by a cable crimp nut 42. Radiopaque markers 16 can be affixed or otherwise coupled to the tongue depressor 14 and to the face mask attachment guide 34 to allow for the positioning of the bite block 10 under x-ray radiography (e.g., planar x-rays and x-ray tomography). FIG. 4 shows an example of the bite block 10 affixed to a face mask 38 using the face mask attachment guide 36, nut 36, and cable crimp nut 42.

[0029] Referring now to FIG. 5, an example of a patient support 50 with an integrated radiopaque marker assembly 52 is shown. FIG. 6 shows an example of a radiopaque marker assembly 52.

[0030] The patient support 50 can be a pillow, cushion, or other suitable patient support. As an example, the patient support 50 can be a head cushion used for support the head and neck of a patient during a radiation treatment procedure.

[0031] The radiopaque marker assembly 52 can include a plate 54 having formed thereon a plurality of radiopaque indicia 56 that enable repeatable and reliable positioned of the patient support 50 to a fixed reference position. For instance, the fixed reference position can be a fixed reference position on the treatment table top. IGRT can then be utilized to post the head tilt/neck position on top of the patient support 50 for efficient, safe, and reproducible setups. In some embodiments, additional radiopaque markers can be embedded in or otherwise coupled to the patient support 50.

[0032] The radiopaque indicia 56 can include, for instance, linear elements composed of a radiopaque material. In some embodiments, the radiopaque indicia 56 are radiopaque wires that are embedded in or otherwise coupled to the plate 54. The plate 54 may be a rigid plate composed of a hard, radiolucent material. The plate 54 may be composed of plastic. The plate 54 is affixed to or otherwise coupled to the patient support 50.

[0033] In some embodiments, the radiopaque indicia 56 can be differently colored to facilitate visual alignment of the patient support 50 with the fixed reference point. By matching a fixed color marker to the reference point (e.g., table top) and then imaging the patient on top of the patient support 50, the location of critical structures that need to be reproduced can be quantitatively assessed.

[0034] The radiopaque indicia 56 can be arranged in a pattern, such as a scale, which may be a distance scale. In such implementations, the radiopaque indicia 56 can be spaced apart by well-defined distances, such that the radiopaque indicia 56 can be relied upon to repeatedly and reliably position the patient support 50 relative to a reference point.

[0035] As one non-limiting example, the patient support 50 can be a head cushion. The radiopaque indicia 56 in the radiopaque marker assembly 52 can include vertical half centimeter marks affixed to the exterior of the cushion, thereby allowing for positioning of the patient's appropriate cervical vertebra at the center of the cushion. Radiopaque markers in the interior of the head cushion are in one-to-one correspondence with the markers affixed to the exterior of the cushion and allow for the x-ray radiographic (planar x-rays as well as x-ray tomography) verification of the positioning of the cervical vertebra relative to the cushion.

[0036] FIG. 7 is a planar x-ray radiograph of bite block and patient support described in the present disclosure. The bite block is shown in the center of the image. Radiopaque markers appear as bright dots in the x-ray radiograph. The head cushion is shown in the lower part of the image. Radiopaque wires appear as bright straight lines of varying lengths.

[0037] The present disclosure has described one or more preferred embodiments, and it should be appreciated that many equivalents, alternatives, variations, and modifications, aside from those expressly stated, are possible and within the scope of the invention.