Question: The ethical defense is on the decision and actions of CMC which made the therac machine.? The document with instru

Introduction to the Therac-25 Major Case Study

This case study is designed to get you to think critically about the ethical issues inherent in our general use of and reliance on

technology. This semester-long activity will help reinforce these

concepts better than short look we take at other cases during the

course. The case study is designed to force students to evaluate peer work, as well as their own, with regards to ethical reasoning and

analysis (something that is stressed throughout the course). To

accomplish this goal, we are going to use the example of the Therac

25 machine, which was used for treating certain cancers. Early in the Therac 25’s use, patients in the U.S. and Canada were reporting burns

from the machine. Ultimately, some deaths occurred. Here is how the

major case study will work:

1. You will choose a client to defend: CMC, FDA, Hospitals, or Operators. See the note below about defending the Hospitals or

the Operators. The choice will be made during week 3 of the

course.

2. You will be tasked with defending the viewpoint of your client in the Therac case. An outline of your defense will be due at the

end of week 6.

3. During week 8 you will write a critique of a defense of one of the

other clients. The defense will be in the form of a Power Point presentation that will be provided along with the week 8 course

materials. Please note that you are NOT creating a Power Point.

You are writing a critique of an existing PP from a previous

semester. 4. Your full defense will be a paper that you will submit at the end

of the 2nd to last week of the course. The paper must, at a

minimum, include:

a. General background information on your client

b. The problem or issue that involved your client with regards to the Therac-25 machine

c. A detailed proposal regarding what can and should be done

to prevent this problem from happening (remedies)

d. An ethical analysis using Spinello’s Framework. This is the place where you stress that your client acted ethically.

e. A list of additional references, beyond the materials

provided in the course.

What you will find out as you investigate this case study and delve into

the inner workings are what really happened and why, and how the

ethical issues, and how they were approached by all interested parties,

shifted and blurred. The outcomes of the Therac 25 law suites are well

known and documented. The point of this case study is not to necessarily change that outcome but rather, it is to increase your

ability to conduct an analysis of the ethical issues given in any

circumstance in the real world.

To get a solid understanding of the Therac 25 problem and the ethical

issues involved, read the chapter sections from both of your textbooks

for this course that deal specifically with the Therac case. Additional

resources are provided in other sections for the Major Case Study. As an aside, we use the case of the Therac machine because it is well

documented and easy to understand. There are of course other cases

out there that are engaging and very interesting as well. The problem

is that many of these cases, such as cases that deal with free speech issues for instance, are difficult to argue because these cases are not

so cut and dried. Legislation is constantly being introduced that would

make it difficult to collect and analyze the necessary data to present a

convincing and conclusive argument within the time frame of this

course and within the legal skills necessary to make sense of the information. The interesting part of this case (with regards to our

course) is how you decide to build your case, and how well you argue

and present it.

NOTE: If you are defending the Hospitals or the Operators, you need

to defend them all. You don’t have to make your defense sound as

though there was only one Hospital, or only one Operator, but, you

can not just ignore one or several Hospitals or Operators to help your defense.

NOTE: Much of the material used in the presentation of this case

study were created by C. Huff, et. al, atSt. Olaf College under a grant

from the National Science Foundation. The material is used under the Education Fair Use Act.

Therac-25 Abstract Therac-25 was a new generation medical linear accelerator for treating cancer. It incorporated the most recent computer control equipment. Therac-25’s computerization made the laborious process of machine setup much easier for operators, and thus allowed them to spend minimal time in setting up the equipment. In addition to making setup easier, the computer also monitored the machine for safety. With the advent of computer control, hardware based safety mechanisms were transferred to the software. Hospitals were told that the Therac-25 medical linear accelerator had "so many safety mechanisms" that it was "virtually impossible" to overdose a patient.

Normally, when a patient is scheduled to have radiation therapy for cancer, he or she is scheduled for several sessions over a few weeks and told to expect some minor skin discomfort from the treatment. The discomfort is described as being like a mild sunburn over the treated area. But in this case on safety critical software, you will find that some patients received much more radiation than prescribed

Therac-25 for Treating Cancer

Therac-25: A computer controlled medical linear accelerator for treating cancer

Normally, when a patient is scheduled to have radiation therapy for cancer, he or she is scheduled for several sessions over a few weeks and told to expect some minor skin discomfort from the treatment. The discomfort is described as being like a mild sunburn over the treated area.

Therac-25 was a new generation machine that incorporated the most recent computer control equipment. The machine targeted electron or X-ray beams on cancerous tissue to destroy it. Electron beams were used to treat shallow tissue, while X-ray beams could penetrate with minimal damage to treat deep tissue.

When a doctor decides that a patient needs radiation therapy, that patient is given a prescription that indicates to the medical linear accelerator operator how many rads (radiation absorbed dose) the patient should receive over how many total treatments. In addition, the prescription indicates the location where the radiation should be applied. The patient schedules a time (or times) to receive treatment.

Standard procedures then determine whether, on any particular appointment, the operator is to set up the equipment for electron or X-ray beam treatment. The patient is asked to lie in the appropriate position on the treatment table and the table is rotated to place the diseased part of the patients' body in the path of, and at the appropriate distance from, the radiation beam. The operator then does whatever mechanical setup is required and leaves the room to program the treatment data into the machine. After doing this, the operator

presses the button that actuates the treatment routine. The patient is then helped off the treatment table and ushered out. After the appropriate forms have been filled out, the next patient is admitted.

Therac-25’s computerization made this laborious process much easier for operators, and allowed them to spend minimal time in setting up the equipment. Operators were thus freed to spend more time talking with and helping the patient.

In addition to making setup easier, the computer also monitored the machine for safety. Previous machines had safety devices as a part of the hardware of the machine. Among other things, these safety devices kept the machine from delivering doses of radiation that were too high. So, with the advent of computer control, these hardware based safety mechanisms were transferred to the software. Hospitals were told that the Therac-25 medical linear accelerator had "so many safety mechanisms" that it was "virtually impossible" to overdose a patient.

How Radiation Therapy Works What Radiation Therapy Is Radiation therapy for cancer is the exposure of cancerous tissue to ionizing radiation. This is usually done by what is called "external" therapy, using electron, X-rays or gamma rays to treat the tissue. This therapy may occur either before or after surgery, or in the place of surgery.

Therac-25 was a 3rd generation radiation therapy machine for external radiation therapy. It used either electron beam or X-rays to treat tissue.

Why Radiation Therapy Works Cancer cells usually multiply faster than most other cells in the body. Tissue composed of these quickly-dividing cells can be shrunken by disabling its genetic material. By doing this, ionizing radiation interferes with the cancerous tissue’s ability to grow.

Unfortunately, the radiation makes no distinction between cancerous cells and other rapidly dividing body tissues. Skin and hair are some of the most noticeably hurt tissues after treatment, and treatment may produce skin lesions and hair loss. These tissues have cells that rapidly divide and the radiation halts their development. But they are usually able to recover from this assault and return to normalcy. Nevertheless, skin lesions and hair loss are not an unusual side effect of radiation therapy.

What a Treatment Session is Like Radiation therapy is usually done in a series of sessions occurring over several weeks, allowing the effect of the radiation to build up over time. The treating doctor will determine the specific number of treatments, the dosage at each treatment, and the schedule. During treatment, the doctor will usually see the patient once a week to check on general health, side effects, and the progress of the treatment.

Before the series of treatments occurs, a radiation therapy technician will outline the specific area to be treated with a marking pen, indelible ink or silver nitrate.

Depending on the body area to be treated, the patient would need to remove his or her clothing and put on a hospital gown. After going to the radiation therapy room, they would then either lie on a treatment table or sit in a special chair (Therac-25 had a table). The marks on the skin are used to guide the machine operator in locating the precise area to be treated. Once the machine is set up, the operator leaves the room for a control room nearby. This protects the operator from prolonged exposure to low-level radiation that might scatter from the machine (an operator may treat as many as 30 patients in a day). From there, the operator will turn on the treatment machine while he/she watches. With the Therac-25, this was accomplished by means of a television camera and monitor. During radiation therapy, the treatment machine makes a buzzing noise. Treatments are typically brief and painless, normally lasting 1 to 5 minutes. Total time in the treatment room will usually be 5 to 15 minutes.

Summary of Operator Interview The following article is the result of an interview we conducted with a Registered Therapy Technologist who has extensive experience operating medical linear accelerators. This individual currently manages a Radiation Therapy Department at a major United States hospital, and trains technicians to operate radiation therapy machinery. For privacy purposes, the true identity of this person will remain anonymous, and for the remainder of the article, we will refer to our interviewee as "Susan."

Susan operated a Therac-4 linear accelerator machine in the mid 1980's. At the time, Susan had recently graduated and was working at a University where the radiation therapy technology was fairly advanced. She enjoyed operating CMC's Therac machine because it was one of the first computerized linear accelerators. Looking back, Susan remembered that while operating the machines, she did not think much about whether there could be computer software "bugs" in the system. The technology was new, and she remembered trusting the machine's components and its designers.

When recalling the advantages of the new computerized machine, Susan reported being able to move more patients through during the day. She also remembered feeling good about the extra time she had to talk with patients when she was working with a computerized machine.

Susan learned about the Therac-25 incidents while attending a national radiation therapy conference in 1990. A radiation therapist who was also a lawyer gave a lecture on the Therac-25 accidents. He handed out newspaper articles about the incidents and spoke about how many times the therapists involved in the accidents attempted to resume treatment in spite of the error messages they received from the computer. The lecture focused on the question of how many attempts to resume treatment is too many? The lecturer and the participants discussed the possibility of establishing institutional policies and limits on the number of times an operator could resume treatment after having received an error message, such as the cryptic "malfunction 54" messages that the operator received during the two fatal accidents in Texas.

The problem, Susan reported, is that back in 1990, and today, there are no industry-wide standards or rules for these types of situations. Susan felt that she had been lucky to have always worked where there was a physicist available to provide help with the many error messages operators received. She also felt that in other clinics, where this kind of assistance is not available, there was, and still is, a great deal more pressure on therapists to just keep going despite the error messages. An operator might attempt, for example, to deliver the prescribed dose in 12 increments instead of 1 by continually clearing the faults generated by the computer. Susan stated that this type of activity happens all the time in medical radiation therapy, particularly in clinics where there is more pressure from the administration to keep patients moving through quickly.

Although Susan had been working with a CMC Therac machine at the time of the accidents, she did not remember receiving warning notices from CMC about the Therac- related accidents. Susan believes that this is one aspect of the industry that has changed, possibly, in part due the Therac-25 accidents. At the present time Susan receives notices from the manufacturers of the linear accelerators used at her hospital whenever there is a linear accelerator malfunction, or even if there is a malfunction that almost occurred, but was prevented.

Perhaps part of the reason that Susan did not hear of the Therac-25 incidents until much later was that the hospital where she worked got rid of the Therac-4, moved their facilities, and bought a new set of linear accelerators. Susan estimated the average life of the linear accelerator to be between 5 and 10 years. After that, she said, the accelerator tends to act somewhat like an old car in which the engine light is coming on all the time. The accelerator's computer generates many faults that can become a nuisance to the operators and to the patients. Responsible operators will continue to report these faults to the physicist, when one is available, and eventually, the machine is replaced.

Susan feels that one of the biggest problems in her industry today is the lack of rigorous industry-wide standard certification and education for operators. Susan reported that there are about 102 radiation schools in the country, and that there are also different types of schools. Students are able to receive a certificate from a certificate program, usually about 12 months in length. Students are also able to receive a four-year bachelor's degree from certain schools. The American Registry of Radiologic Technologists (ARRT) provides a test that graduates of these programs may then take in order to be considered licensed entry level technicians. The ARRT also requires that therapists maintain their training through continuing education. Therapists must have 24 credits in two years before they may re-register their licenses.

In spite of the fact that the ARRT provides these guidelines for licensure, many states in the U.S. do not require hospitals or clinics to hire licensed radiation therapists. Some states require very basic exams, but, according to Susan, that in essence means that in many states anyone off the street could learn how to operate a machine, take one of these basic exams, and then be qualified to operate radiation therapy machines.

Susan and many of her colleagues continue to fight for mandatory standard certification of radiation therapists. The safety of patients depends on all of the elements of their systems of treatment working together correctly. The more operators are trained to know about the process, the more they will be able to help prevent accidents. Well-trained operators can double-check radiation dose prescriptions and question doctors when something does not seem right. With the benefit of extensive training, operators have a better sense of when it is alright to over-ride a fault message from the computer.

Well trained technicians will also be better equipped to stand up to hospital administrations that attempt to put pressure on technicians to push large numbers of patients through treatment in spite of possible dangers. Though Susan does not feel this kind of pressure from her own administration, she knows that other technicians in other

clinics definitely do, especially at "free-standing" clinics that operate for profit. Susan is aware that at these clinics there is a tremendous amount of pressure put on machine operators to get patients through treatment.

Susan also described incidents in which technicians left institutions because they didn't feel that the institutions' radiation therapy practices were safe for patients. Because there is no federal law regulating how many times an operator can re-attempt therapy after the computer displays a fault or shuts down, some operators allegedly use jumper cables that continuously override their computer's emergency shut down mechanism. Susan cited a lack of regulation, lack of training, and lack of adequate funding as reasons for these procedures.

Another issue in the radiation therapy industry that worries Susan is the fact that linear accelerator manufacturers charge large fees for operator training sessions, software upgrades, and machine maintenance contracts. When a radiation therapy machine is purchased, it comes with many binders full of information provided by the company. The clinic is given the option to buy service contracts and send physicists and operators to the company headquarters for training. Susan reported that in many clinics where money is tight, administrators are forced to choose between machine servicing contracts, software upgrades, and training.

According to Susan, mistakes are still made in the radiation therapy treatment of patients. Much of the information and calibration is still done by human beings and subject to human error. As an instructor, Susan teaches her students to anticipate every angle of the treatment, and then to check, and re-check their work. Susan also mentioned that while she teaches her students not to trust wholly in the machinery and its software, operators are largely dependent on manufacturers and hospital physicist teams to keep the machines running correctly.

Susan has a positive outlook regarding the radiation therapy industry. She knows that thousands of patients benefit greatly from radiation therapy technology. While Susan continues to push for operator certification legislation, she focuses on training her own staff well. Susan and her administration also focus heavily on quality patient care.

When asked if she thought it would be important for the designers of the software that runs the machines to know what it is like to do her job, Susan's reply was an emphatic yes, though she doubted many of the software designers of her machinery had spent much time observing a radiation treatment facility.

Accident Accounts Linda Knight: June 3,1985

61-year old Linda Knight had been receiving follow-up treatment at the Kennestone Regional Oncology Center (Marietta, GA) for the removal of a malignant breast tumor. On June 3, staff at Kennestone prepared Knight for electron treatment to the clavicle area, using the Therac-25 machine.

Knight had been through the process before, which was ordinarily uneventful. This time, when the machine was turned on, Knight felt a "tremendous force of heat… this red-hot sensation." When the technician re-entered the therapy room, Knight said, "you burned me." The technician replied that that was "not possible."

Back home, the skin above Knight's left breast began swelling. The pain was so great that she checked in at Atlanta's West Paces Ferry Hospital a few days after the Therac incident. For a week, doctors at West Paces Ferry continued to send Knight back to Kennestone for Therac treatment, but when the welt on her chest began to break down and lose layers of skin, Knight refused to undergo any more radiation treatment.

About two weeks later, the physicist at Kennestone noticed that Knight had a matching burn on her back, as though the burn had gone through her body. The swelling on her back had also begun to slough off skin. Knight was in great pain, and her shoulder had become immobile. These clues led the physicist to conclude that Knight had indeed suffered a major radiation burn. Knight had probably received one or two radiation doses in the 20,000-rad (radiation absorbed dose) range, well above the typical prescribed dosage of around 200-rads. The physicist called CMC and, without telling of the accident, asked questions about the likelihood of radiation overexposure from the Therac 25 machine: Could Therac 25 operate in electron mode without scanning to spread the beam? Three days later CMC engineers called back to say this was not possible.

Linda Knight was in constant pain, lost the use of her shoulder and arm, and her left breast had to be removed because of the radiation burns.

Donna Gartner: July 26,1985

Donna Gartner, a 40-year old cancer patient, was at the Ontario Cancer Foundation clinic in Hamilton, Ontario, Canada for her 24th Therac treatment for carcinoma of the cervix.

The Therac-25 operator activated the machine, but after 5 seconds, the Therac-25 shut down and showed an "H-tilt" error message. The computer screen indicated that no dose had been given, so the operator hit the "P" key for the "proceed" command. The Therac shut down in the same manner as before, reading "no dose," so the operator repeated the process a total of four times after the initial try.

After the fifth try, a hospital service technician was called but found no problems with the machine. Donna Gartner left the clinic and the Therac was used with six other patients that day without any incidents. However, despite the fact that the Therac had indicated that no radiation dose had been given during Donna Gartner's five therapy attempts that day, Gartner complained of a burning sensation she described as an "electric tingling shock" in the treated area of her hip.

Gartner returned for treatment three days later, on July 29, and was hospitalized for suspected radiation overexposure. She had considerable burning, pain and swelling in the treatment region of her hip. The Hamilton clinic took the Therac-25 machine out of service and informed CMC of the incident. This was the first time CMC had heard from a clinic about an overdose problem with the Therac-25 machine. CMC sent a service engineer to investigate.

CMC reported to a range of stakeholders that there was a problem with the operation of Therac 25. The FDA, the Canadian Radiation Protection Board (the parallel Canadian agency to the FDA), and other Therac-25 users were all notified. Users were instructed to visually confirm that the Therac turntable was in the correct position for each use.

Because of the Hamilton accident, CMC issued a voluntary recall of the Therac-25 machines and the FDA audited CMC's modifications to the Therac. CMC could not reproduce the malfunction that had occurred but suspected some hardware errors in a switch that monitored the turntable position. A failure of this switch could result in the turntable being incorrectly positioned, and an unmodified electron beam striking the patient. The company redesigned the mechanism used to lock the turntable into place, redesigned the switch to detect position and it accompanying software. They then reported in November 1985 that this redesign was complete and that, given their safety analyses, the machine was now at least 10,000 times safer than before.

Donna Gartner died on November 3, 1985 from cancer. An autopsy revealed that had the cancer not killed Gartner, a total hip replacement would have been necessary because of the radiation overexposure.

Janis Tilman: December 1985

Janis Tilman was being treated with the Therac-25 machine at the Yakima Valley Memorial Hospital in Yakima, Washington. After one treatment in December 1985, her skin in the treatment area, her right hip, began to redden in a parallel striped pattern. The reddening did not immediately follow treatment with the Therac-25 because it generally takes at least several days before the skin reddens and/or swells from a radiation overexposure.

Tilman continued Therac treatment until January 6, 1986 despite the reddening, since it was not determined that the reddening was an abnormal reaction. Hospital staff monitored the skin reaction and searched unsuccessfully for possible causes for the striped marks.

The hospital sent a letter to CMC and spoke on the phone with CMC's technical support supervisor, who later sent a written response stating, "After careful consideration, we are of the opinion that this damage could not have been produced by any malfunction of the Therac-25 or by any operator error." The hospital staff dismissed the skin/tissue problem as "cause unknown," partly due to the response from CMC, and partly because they knew CMC had already installed additional safety devices to their Therac-25 machine in September 1985.

Upon investigation in February 1987, the Yakima staff found Tilman to have a chronic skin ulcer, dead tissue, and constant pain in her hip, providing further evidence for a radiation overexposure. Tilman underwent surgery and skin grafts, and overcame the incident with minor disability and some scarring related to the overdose.

Isaac Dahl: March 22, 1986

At the East Texas Cancer Center (ETCC) in Tyler, Texas, 33-year old Isaac Dahl was to receive his ninth Therac-25 radiation therapy session after a tumor had been successfully removed from his left shoulder. By this time the Therac 25 had been in successful operation at Tyler for two years, and 500 patients had been treated with it.

The Therac-25 operator left the radiation room to begin the treatment as usual. As she was typing in values, she made a mistake and used the "cursor up" key to correct it. Once the values were correct, she hit the "B" key to begin treatment, but the Therac-25 machine shut down after a moment, and the message "Malfunction 54" showed on the control room monitor. The machine indicated that only 6 of the prescribed 202 units of radiation had been delivered. The screen of the console showed that this shut down was a "treatment pause" which indicated a problem of low priority (since little radiation had been delivered). The operator hit the "P" key to proceed with the therapy, but after a moment of activity, "Malfunction 54" appeared on the Therac control screen again.

The operator was isolated from Dahl because the Therac-25 operates from within a shielded room. On this day at the ETCC, the video monitor was unplugged and the audio monitor was broken, leaving no way for the operator to know what was happening inside. Isaac Dahl had been lying on the treatment table, waiting for the usually uneventful radiation therapy, when he saw a bright flash of light, heard a frying, buzzing sound, and felt a thump and heat like an electric shock.

Dahl, knowing from his previous 8 sessions that this was not normal, began to get up from the treatment table when the second "attempt" at treatment occurred. This time the electric-like jolt hit him in the neck and shoulder. He rolled off the table and pounded on the treatment room door until the surprised Therac-25 operator opened it. Dahl was immediately examined by a physician, who observed reddening of the skin but suspected only an electric shock. Dahl was discharged and told to return if he suffered any further complications.

The hospital physicist was called in to examine the Therac-25, but no problems were found. The Therac-25 was shut down for testing the next day, and two CMC engineers, one from Texas and one from the home office in Canada, spent a day at the ETCC running tests on the machine but could not reproduce a Malfunction 54. The home office engineer explained that the Therac-25 was unable to overdose a patient and also said that CMC had no knowledge of any overexposure accidents by Therac-25 machines. No electrical problems were found with the ETCC's Therac machine, and it was put back into use on April 7, 1986.

Isaac Dahl's condition worsened as he lost the use of his left arm and had constant pain and periodic nausea and vomiting spells. He was later hospitalized for several major radiation-induced symptoms (including vocal cord paralysis, paralysis of his left arm and both legs, and a lesion on his left lung). Dahl died in August of 1986 due to complications from the radiation overdose.

Daniel McCarthy : April 11,1986

Technicians could find nothing wrong with the Therac-25 unit at the East Texas Cancer Center (ETCC), after the "Malfunction 54" incident that had injured Isaac Dahl. The machine was reinstated.

Four days later, Daniel McCarthy was being treated for skin cancer on the side of his face. The same Therac operator who had treated Isaac Dahl was treating McCarthy. As the operator prepared to administer the Therac treatment from the control room, she used the "cursor up" key to correct an error in the treatment settings. She then began treatment using the "B" key.

The Therac-25 shut down within a few seconds, making a noise audible through the newly repaired intercom. The Therac monitor read "Malfunction 54." The operator rushed into the treatment room and found McCarthy moaning for help. He said that his face was on fire. The hospital physicist was called. McCarthy said that something had hit the side of his face, and that he had seen a fl

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