Immobilization Device for Radiation Therapy Fall 2016

In the developing world, one of the most accessible and affordable treatments for cancer is radiation therapy. In order for radiation therapy to be effective, the radiation must be targeted specifically to the area affected by the cancer. This requires the use of an immobilization device to keep the patient in a fixed position with the least amount of movement possible, and for this position to be replicable between treatments. For breast cancer specifically, such a device must allow for the patient’s torso to be positioned at a desired angle that allows for the best possible targeting of the radiation therapy to the thoracic region. While such devices are already being manufactured in developed nations, they cost thousands of dollars and are not readily obtained in the developing world.

The goal of this project in the broadest sense is to create such a device that is effective at keeping patients immobilized with their torso propped up at a desired angle, while ensuring that the materials are both cheap and available in the developing world.

Step 1: Materials & Tools

Materials:

1 Pine 2x12x12

1 Pine 4x4x8

1 Pine 1x4x12

1 Circular Pine Fence Post

1 1in diameter x 18in long dowel rod

~10oz of wood glue

12 8x1-5/8in deck screws

Latex Paint/Primer

2 Hinges

Epoxy

Tools:

Table saw

Band saw

Jig saw

Milling Machine

Electric Powered Handsaw

Jointer

Chop saw

Drill

Paint Brush

Step 2: Cuts

Refer to images for measurements and relative locations of cuts.

2x12x12

Using the table saw, cut the 2x12x12 into the following pieces:

-Two 42" length pieces

-Two 21.5" length pieces

Using the jig saw, cut a rounded hole out of the edge of each 21.5" piece as shown in the drawing labeled SHORT. The hole should be 3.5" wide at the base, 3" tall, and begin 2" from the bottom of the board.

These will be used to form the main body of the board, divided into the upper and lower sections.

4x4x6

Using the chop saw, cut the 4x4x6 into the following pieces:

-Two pieces that are 9.74" tall on the back end and 10.87" tall on the front end. Use the chop saw at an angle of 15 degrees for the first cut and then 0 degrees for the second cute so that the length and angle are exactly the same for both blocks.

-Two pieces that are 6.58" tall on the back end and 7.29" tall on the front end. Use the chop saw at angle of 10 degrees for the first cut and then 0 degrees for the second cut so that the length and angle are exactly the same for both blocks.

-Two pieces that are 3.31" tall on the back end and 3.66" tall on the front end. Use the chop saw at angle of 5 degrees for the first cut and then 0 degrees for the second cut so that the length and angle are exactly the same for both blocks.

These pieces will form the angled blocks that hold the breast board up at an angle.

1x4x10

Using the table saw, cut the 1x4x10 into the following pieces:

-Three 22" length pieces (or whatever twice the width of the 2x12x12 board is - it may not be exact)

These pieces will be used as the supports across the back of the main boards.

Dowel Rod

Using the chop saw, cut the dowel rod into the following pieces:

-Eight 2" length pieces

These will be used as the pegs that attach the angle blocks and butt stop to the board.

Pine Fence Post

Using the chop saw, cut the pine fence post into the following pieces:

-One piece 22" in length (or whatever twice the width of the 2x12x12 board is - it may not be exact)

Then, using the jointer cut the pine fence post in half lengthwise. This should result in two pieces 22" in length with a semicircular cross section.

Step 3: Notching & Drilling

Refer to images for locations and dimensions of notches and holes.

Notching

The notches will be used as a space to hold the 1x4 planks that go across the back of the 2x12 boards as supports.

Using the mill, make notches that span the entire width of the board, about 3.5" tall (or whatever the exact width of the 1x4 is), and about 3/4" deep (or whatever the exact thickness of the 1x4 is) by covering the entire area with at about 1/10" of depth at a time. Alternatively, you can raise the blade on a table saw the correct thickness and go 1/8 in of length at a time down the width. Make notches at the following locationsL

-10" from one end of both 42" 2x12s boards. Make sure the notches line up across both boards when placed side by side so that the 1x4 support will fit when the boards are glued together.

-7 1/2" from the other end of both 42" 2x12 boards. Make sure the notches line up across both boards when placed side by side so that the 1x4 support will fit when the boards are glued together.

-9" from one end of both 21.5" 2x12 boards. Make sure the notches line up across both boards when placed side by side so that the 1x4 support will fit when the boards are glued together.

Drilling Holes

-Drill holes that are 1" deep and 1" in diameter with centers in the locations shown in the images above on the 2x12 boards.

-Drill holes that are 1" deep and 1" in diameter into the exact center of each of the angled 4x4 blocks.

-Drill two holes that are 1" in deep and 1" in diameter with centers 9" apart at the top end of the 21.5" 2x12s - this is the end that will be hinged to the 42" 2x12s.

-Drill two holes that are 1" deep and 1" in diameter with centers 11" (or however far apart the holes in the center of the 2x12 boards are) in the flat side of the semicircular pine fence post. These holes should be exactly lined up with those in the board so that once the pegs are glued in to the butt stop, they will fit in the holes on the board.

Step 4: Gluing

Top Boards:

1. Apply wood glue liberally to the inside edge of one of the top boards. This should be the edge of the board that does not have the semicircular section cut out.

2. Lay the board on a flat surface and push the corresponding edge of the other top board against the glue. Both semicircular cutouts should be on the outside edges of the glued together board.

3. Apply clamps so that the glued portion of the boards are held firmly together, without clamping so hard that the boards buckle and are no longer flat on the ground or other surface they are laying on.

4. Leave boards clamped for at least 8 hours, and allow the glue at least 24 hours total to dry before moving the boards.

Bottom Boards:

1. Apply wood glue liberally to the inside edge of one of the bottom boards. The inside edge of each board can be determined by looking at the back of the boards and lining up the holes drilled for the index, making sure that they are the correct width apart.

2. Lay the board on a flat surface and push the corresponding edge of the other bottom board against the glue.

4. Leave boards clamped for at least 8 hours, and allow the glue at least 24 hours total to dry before moving the boards.

Butt Stop:

1. Apply wood glue liberally to one end of each peg and place one in each hole drilled in the butt stop.

2. Clamp each peg into place. Leave pegs clamped for at least 8 hours, and allow the glue at least 24 hours total to dry before moving the butt stop.

Angle Blocks:

1. Apply wood glue liberally to one end of each peg and place each in its corresponding hole cut in the top of the blocks.

2. Clamp each peg into place. Leave pegs clamped for at least 8 hours, and allow the glue at least 24 hours total to dry before moving the butt stop.

Step 5: Epoxy

1. Fill each hole drilled in the back of the bottom board in with epoxy and let the epoxy cure for 24 hours.

2. A 0.5" hole will need to be drilled into each well of epoxy. Mark the center of each hole so that the centers are square with the top of the board and exactly 9" apart.

3. Drill 0.5" holes in the epoxy, centered at the points marked in Step 2. begin by drilling a very small hole and gradually increase the size of the drill bit until reaching 0.5".

**Note: it is important that the holes be drilled as straight up and down as possible. Use a drill press if available.**

Step 6: Paint & Assembly

1. Paint all components of the board: the top half, bottom half, butt stop, and angle blocks.

**Note: be careful not to paint dowels or holes so that they still fit together, or drill slightly larger holes to account for paint thickness.**

2. Once paint has dried, write the corresponding angle (in degrees) on the back of each set of angle blocks.

3. Screw hinges on the front of the top board, one on each edge as far towards the outside of the board as possible.

4. Line bottom board up so that the holes for the butt stop are closest to the top board. Fasten the two boards together by screwing the free end of the hinge onto the bottom board.