Treatment Begins

On November 18 Steve received his first proton treatment. We found it fitting that on this day, his 63rd birthday, he would begin a new lease on his life. It began at 8:00am when he arrived at the reception area to check in. His appointment was a at 9:00am but they want you there 30 minutes early and he was anxious to get started. He had already had his "pod" made so all was ready.

The first thing you do upon arrival is drink 16 ounces of water about 20 minutes prior to the procedure in order to fill your bladder. This helps to stretch the bladder and lift it off the prostate and away from the target area of the proton beam. (Steve drank 20 oz just to be sure). When they called his name he went in and changed into this beautiful gown that even had air conditioning. Nothing but the best here!

Just one more glass!

Now unlike other types of radiation therapy that use x-rays to destroy cancer cells, proton therapy uses a beam of special particles called protons. Doctors can better aim and control the energy of proton beams onto the tumor, so there is less damage to the surrounding healthy tissues. This allows doctors to use a higher dose of radiation with proton therapy than with x-rays. This proton beam is precisely shaped in three dimensions and delivered to the prostate with extreme precision. For the radiation to be precisely targeted, you must be placed in the exact same position for each treatment. Customized devices, called pods, are built for each patient (body mold) to allow the proton radiation to conform, three-dimensionally, to the target site.

To back up just a little: On October 27th Steve climbed onto the pod which was lined with a soft fabric. The technician poured warm polyurethane between the PVC pod and the sheet on which he was lying. This produced a mold that conformed to his body and would keep him motionless while being treated. After a couple of days it sets and is all ready for you.

Steve in "his" pod

This might get a little more technical than even I feel comfortable with but this is such an important subject we can't just say "he lays down and they zap him with a proton beam". Prostate cancer is every man's dread and every man's future. So we want to accurately present this wonderful treatment properly.

The precision of the proton beam requires equal precision in planning and delivery. This is done in two steps: (1) a three-dimensional reconstruction of the prostate or tumor and its relationship to surrounding structures. The three-dimensional information is obtained by performing CT scans - in about 20 minutes they take ninety-eight or so pictures in the prostate region . These pictures are used to produce a three dimensional "hologram" of the prostate which the oncologists, physicists and dosimetrists use to plan his treatment. This information is also used to construct two custom-made focusing devices called an aperture and a bolus, which are used together to conform the proton beam to the precise target area. (2) a reproducible treatment position that minimizes movement errors. (Steve's pod as described earlier)

Bolus used to shape proton beam

So, yesterday Steve climbed into his pod and let the technicians do their thing. With laser beams as guides, his was moved to a position within half a centimeter of the calculated optimal position. To make the position more precise, the radiation therapy technologist obtains several low-power diagnostic digital images. Distances from various bone landmarks to the isocenter are measured on these daily images. These are compared to identical measurements made on computer-generated films based on the planning CT scan. Usually it is necessary to move the patient a few millimeters to make the position conform exactly to the prescribed treatment. Now his specially created aperture and bolus, mentioned above, were loaded into the beam line. Each of these devices are identified by a bar code, which must be scanned by a laser scanner (similar to those at a supermarket). A match must be made before the computer will permit a treatment to begin.

The proton journey to the prostate begins! It is really complicated and hard to follow so I am going to try and write it in simple english and still do it justice. The protons are sent through a vacuum tube within a pre-accelerator which boosts their energy to two million electron volts. They travel around a synchrotron about 10 million times per second which also increases it energy to between 70 to 250 million electron volts. The voltage achieved is enough to place them at any depth within the patients body.

Model of accelorator facility

The treatment rooms have gantries which are wheels 35 feet in diameter and weigh approximately 90 tons, which revolve around the patient to direct the beam precisely to where it is needed. From Steve's perspective, however, all that is visible is a revolving, cone-shaped aiming device. Each treatment room has a guidance system to direct and monitor the beam until it enters the patient in precisely the location and shape that the doctors have predetermined.

Final alignment of delivery device

The entire proton facility is controlled by computers that are equipped with safety measures to ensure that patients receive proton radiation treatments as prescribed. They also have cameras and microphones if the patients need the technicians at any time. The entire process takes about 3 minutes in the pod. What a wonder of technology!!!

Now we will settle into a routine that works around his treatment times which vary from day to day. Yesterday was 9am, today was 12 noon and tomorrow is 9pm. I know, it's crazy, don't ask me who there scheduler is!