Deflection compensating mechanism for patient imaging table
When inserting a patient into a bore of a patient imaging device (e.g., CT, SPECT, PET, MRI, fMRI, etc.), a cantilevered pallet supported by an adjustable table deflects under the patient's weight. A pair of springs couples the table to first and second support arms, which are coupled to each other at a pivot point. A lever is coupled to the front end of the table and pivots on a fulcrum. A pair of wires are coupled to a rearward end of the lever and passed over respective pulleys before being coupled to a rearward portion of the table. A component of the patient's weight applied to the front edge of the table causes the lever to pivot on its fulcrum, raising the forward ends of the wires, which pass over the pulleys and pull the rearward end of the table downward to maintain the patient at a desired altitude and/or angle.
1. A patient support table system, comprising:
a table portion that supports a patient pallet for longitudinal translation to cantilever the pallet from the table portion, patient weight causing a cantilevered portion of the pallet to deflect axially;
a first means for generating electrical or mechanical feedback indicative of pallet deflection;
a second means for tilting the table portion to compensate for the pallet deflection;
wherein the first means includes:
a first spring that couples a front end of the table portion to a first support arm; and
a lever, coupled to the front end of the table portion, that pivots on a fulcrum point.
2. The patient support table system according to claim 1 , wherein the second means tilts the table portion such that a portion of a patient cantilevered a preselected distance from the table portion maintains a constant altitude and angle to horizontal as the pallet translates longitudinally such that a greater or smaller portion of the pallet is cantilevered from the table portion.
3. The patient support table system according to claim 1 , wherein the second means includes a pair of wires with forward ends coupled to rearward end of the lever and passed over respective pulleys, with the pulleys and rearward ends of the wires coupled to a rearward portion of the table portion such that pivoting of the lever on the fulcrum causes the rearward portion of the table portion to move downward.
4. The system according to claim 3 , wherein the pallet supports a patient and translates longitudinally into an examination region of a scanning device, the examination region being the preselected distance from the table portion.
5. The system according to claim 4 , wherein as the pallet translates forward, the force exerted by the weight on the front end of the table portion increases and forces a front end of the lever downward, pivoting the lever about the fulcrum point and pulling substantially upward on the forward ends of the wires, the upward force exerted on the wires being converted by the pulleys to a downward force on the rearward portion of the table portion.
6. A diagnostic imaging system, comprising:
a diagnostic imager with an examination region; and
the patient support table according to claim 1 .
7. A method of supporting a patient during an examination, comprising:
supporting a patient pallet on a table portion for longitudinal translation to cantilever the pallet from the table portion, patient weight causing a cantilevered portion of the pallet to deflect axially;
generating electrical or mechanical feedback indicative of pallet deflection, the feedback being generated via a first spring that couples a front end of the table portion to a first support arm, and a lever, coupled to the front end of the table portion, that pivots on a fulcrum point; and
tilting the table portion to compensate for the pallet deflection.
8. The method according to claim 7 , wherein the table portion is tilted such that a portion of a patient cantilevered a preselected distance from the table portion maintains a constant altitude and angle to horizontal as the pallet translates longitudinally such that a greater or smaller portion of the pallet is cantilevered from the table portion.
9. The method according to claim 7 , further comprising pivoting the lever on the fulcrum to cause a rearward portion of the table portion to move downward via a pair of wires with forward ends coupled to rearward end of the lever and passed over respective pulleys, with the pulleys and rearward ends of the wires coupled to the rearward portion of the table portion.
10. The method according to claim 9 , further comprising supporting on the pallet and translating the pallet longitudinally into an examination region of a scanning device, the examination region being the preselected distance from the table portion.
11. The method according to claim 10 , wherein as the pallet translates forward, the force exerted by the weight on the front end of the table portion increases and forces a front end of the lever downward, pivoting the lever about the fulcrum point and pulling substantially upward on the forward ends of the wires, the upward force exerted on the wires being converted by the pulleys to a downward force on the rearward portion of the table portion.
12. A patient support table feedback system, comprising:
a first spring that couples a front end of a table portion to a first support arm;
a lever, coupled to the front end of the table portion, that pivots on a fulcrum point;
wherein the table portion supports a patient pallet for longitudinal translation to cantilever the pallet from the table portion, patient weight causing a cantilevered portion of the pallet to deflect axially; and
wherein the first spring and the lever cooperate to generate feedback information indicative of pallet deflection.
13. The patient support table feedback system according to claim 12 , wherein the table portion is tiltable such that a portion of a patient cantilevered a preselected distance from the table portion maintains a constant altitude and angle to horizontal as the pallet translates longitudinally such that a greater or smaller portion of the pallet is cantilevered from the table portion.
14. The patient support table feedback system according to claim 12 , further including a pair of wires with forward ends coupled to rearward end of the lever and passed over respective pulleys, with the pulleys and rearward ends of the wires coupled to a rearward portion of the table portion such that pivoting of the lever on the fulcrum causes the rearward portion of the table portion to move downward.
15. The system according to claim 14 , wherein the pallet supports a patient and translates longitudinally into an examination region of a scanning device, the examination region being the preselected distance from the table portion.
16. The system according to claim 15 , wherein as the pallet translates forward, the force exerted by the weight on the front end of the table portion increases and forces a front end of the lever downward, pivoting the lever about the fulcrum point and pulling substantially upward on the forward ends of the wires, the upward force exerted on the wires being converted by the pulleys to a downward force on the rearward portion of the table portion.
17. A diagnostic imaging system, comprising:
a diagnostic imager with an examination region; and
the patient support table according to claim 12 .