how the linear accelerator works in therapy - straight line laser

Sandra fried land
1985 this is a digital version of an article from The Times Print Archive, before it starts online in 1996.
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Doctors have been using radiation to destroy cancer cells since 1898, when they first inserted radioactive needles and glass tubes filled with laser powder into the patient's body.
Although radioactive implants can still be used to increase the amount of radiation in the tumor site, most radiation treatments are now provided by linear accelerators or old equipment with radioactivitycobalt core.
Both types of machines are called millivolt units because they generate millions of volts of energy (
Giant 1 million v battery). The $1.
Newark University Hospital New Jersey Cancer Center's 1 million accelerator is the most powerful of the 29 linear accelerators currently running in the state hospital.
The center's advertising therapist says the machine can treat tumors almost anywhere in the body with great precision and can minimize damage to nearby bones, organs, muscles and nerves.
The unit produces two types of radiation: * photons or X-
Ray beams that penetrate the body to the depths-
A sitting tumor that includes the prostate, colon, liver, or ovary.
* Electron beam with less penetration than X-
But more light is created.
Uniform field of radiation.
These beams do not illuminate the things below the tumor;
They are used for skin cancer and tumors close to the surface, as well as for head and neck tumors where it is critical to avoid brain or spinal cord under cancer.
When the electrons accelerate in a straight line, both beams of light are generated, which is a complex process that gives the machine a name.
In microseconds, the device enables stationary electrons to move at speeds close to the speed of light.
186,000 miles per second. When these are high
The velocity electrons are emitted onto the tungsten target inside the machine, they release a stream of photons and then target the patient.
The doctor can choose a photon beam of 8 or 18 megabytes.
Beams with higher energy are used to penetrate deeper or heavier patients.
If the tungsten target is removed, then the electron itself will reach the patient.
Depending on the type and location of the tumor, doctors can order one of the 8 different electron beams ranging from 5 to 20 megabytes.
In interoperative radiation therapy, everything above the tumor site is transferred to one side, and the doctor uses an electron beam to deliver a lot of radiation to the tumor without hurting anything below.
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Christopher Hawkins, chief medical physicist at the Cancer Center, helped doctors tailor radiation treatments for each patient.
Computer processing-
Planning the system, he can show how various voltage and beam angles distribute radiation in the patient's body.
In order to limit radiation damage to healthy tissues, approximately 25 treatments of the same dose are usually given within five weeks.
Advertisements include patient positioning, and while the actual treatment lasts only 3 minutes, it takes about 15 minutes for each treatment.
According to Dr, most side effects are temporary and limited to areas under treatment
Joseph Del Carmen, a radiation oncologist at the center.
For example, she said that treatment through the throat or esophagus may cause difficulty in swallowing, and patients treated through the lungs may have some difficulty breathing. ''Pre-
Drug therapy helps alleviate the nausea and vomiting that some patients develop after abdominal therapy, Dr. ''
Del Carmen said he added that after two months of treatment, the hair lost in the head began to grow back.
Richard Jalonack, assistant director of radiation oncology at Cancer Center, pointed out that at first, some patients were shocked by the "future" look of the linear accelerator and treatment room, which was made up of a round, eight-foot-
The diameter "face" of the equipment ".
The lamp remains dark, helping to place the red laser beam of the accelerator cross over the patient's body. A 6,500-
Pound lead will separate the patient from the technician running the accelerator and watch the operation in both colors
TV monitor
They can talk to patients and hear their answers.
The word "just radiation" is terrible, "said Mr. Jalonack said.
"But radiation technology experts talk to a nurse and patient to show them the machines and ease their fears.
After the first two treatments, most patients were relaxed.
They found that there was no harm, and all they had to do was keep it still.
"A version of this article was printed on page NJ11 of the National edition on December 8, 1985, with the title: How the linear accelerator works in treatment.