P&S Journal: Winter 1997, Vol.17, No.1
We Make Great PETs:
By Kristen Watson
A Day in the
Danielle Allen, PET office supervisor, and Jason De Salvo, the PET Center's
general manager, left, reschedule an appointment, while Dr. Ernest De Salvo, director of the Kreitchman PET Center, and Dr. Angela Lignelli, PET radiology
fellow, right, discuss a patient's file.
Photo by Jonathan Smith
The Scene: The Morton A. Kreitchman PET Center
The Protagonist: The PET scanner
The Players (in order of appearance):
An overweight, middle-aged male cardiac patient
A 9-year-old boy with seizure disorder
An elderly male cancer survivor
A middle-aged male diabetic cardiac patient
Supporting Cast (in order of appearance):
Danielle Allen, PET Center office supervisor
Dr. David Pinsky, assistant professor of medicine
Chitra Manoj, senior technologist of the PET suite
Irena Gottlieb, part-time technologist
Leo Delacruz, chief technologist of the PET suite
Dr. Angela Lignelli, PET radiology fellow
Dr. Jeff Plutchok, postdoctoral residency fellow in nuclear medicine
Dr. Kenneth Sampong, postdoctoral clinical fellow in medicine
Dr. Ernest De Salvo, PET Center clinical coordinator
Decisions Made Easier
A Tour of the Morton A. Kreitchman PET Center
"We feel like we live here," the overweight, middle-aged man, accompanied by his wife, tells Danielle Allen, the PET Center office supervisor, as he enters the center's administrative office. He has an appointment for a cardiac scan and has come to settle a few details before he is led upstairs for the procedure. He's spent a lot of time at the hospital lately: He had an X-ray taken the day before and was an inpatient after a heart procedure a few weeks ago.
The patient's wife fills out a consent form and some other paperwork because her husband is restless. He'd rather sit and listen to Howard Stern on his mini Sony Sports Walkman radio. "Are you nervous?" Ms. Allen asks. The patient takes off his earphones and answers, "I don't like the idea of the tube," he says, referring to the scanner. "It's not a tube, really," she assures him. "It's more like a doughnut." Ms. Allen continues to explain that the scanner will surround his torso, and his head and legs will stick out the ends of the machine. The patient seems somewhat relieved.
On the way to the third floor PET suite, Ms. Allen briefs the patient on what to expect during the next few hours: "You'll have an IV isotope injection, they'll wait 30 to 50 minutes for the injection to settle, and then they'll start the scan. It'll all take at least two and a half hours."
Chitra Manoj, senior technologist, left, observes
a patient's transmission scan on the monitor, while Dr. Angela
Lignelli, PET radiology fellow, reviews a patient's films
on the film illuminator with Dr. Paul Lang,
postdoctoral residency fellow in radiology.
When they arrive in the PET suite, the technologists realize the patient's size might present a problem. During a practice run, they determine he will have to squeeze his shoulders in toward his chest to fit into the scanner, a position uncomfortable, if not impossible, to maintain for the amount of time he needs to keep still. It is necessary to take several scans, and the patient's alignment must be identical in each for the scans to match up. After just a few minutes of trying to fit the patient into the scanner, the man says he feels claustrophobic and doesn't want to attempt the scan in such an uncomfortable position.
The doctors back off and give the patient a little breathing room. "I always let the patient guide me," says Dr. David Pinsky, assistant professor of medicine. "I make my recommendation and let the patient decide. We can scan this patient if he cooperates." With this, he calls the referring physician and leaves a message; perhaps that doctor can convince the patient the discomfort is worthwhile. After about 20 minutes go by with no word from the referring physician, Dr. Pinsky tells the patient he's free to go home.
T he next patient, a 9-year-old boy with a developmental disorder, comes barreling down the hallway to the administration office. In an effort to head off a tantrum, Ms. Allen and the patient's mother ask the boy for his telephone number, school, and age as they make their way to the PET suite.
This patient is quite hyper and will have to be sedated to keep him still during the brain scan. The radioactive material must be injected before the sedative. Nervous at the sight of the first needle, the boy cries, "No needle!" and tries to remove the needle during the injection. "No, no. Don't touch," the technologists warn. "Take it out and we'll have to do it again."
Chitra Manoj, assistant clinical coordinator of the PET suite, comforts the restless patient, patting his back and saying, "Good boy, very good boy. Do you like Power Rangers?" The patient still looks upset and confused when the second needle arrives from the cyclotron. His mother tells him, "That's not for you" to calm him. The boy struggles, kicks, and cries when the technologists try to sedate him. Finally, silence, then a chorus of "What a good boy!" Ms. Manoj walks back into the observation room saying, "Children are always difficult."
A pulse oximeter is attached to the boy's finger to read the oxygen content of his blood during sedation. His mother kisses his cheek and strokes his face and hair to encourage him to sleep. A hush fills the room while everyone waits for the sedative to take effect.
Once sedated, the patient is moved from a stretcher to the gurney that slides inside the scanner. The technologists position him so his head is just under the arch on the scanner. Technologist Irena Gottlieb goes behind the scanner to adjust the child's head through a hole in back of machine. Only the bottoms of the boy's sneakers and his khaki green pants above them are visible from the observation room.
The doctors use the time during the scan to question the patient's mother about her son's medical history. "He was born normal, but regressed," the mother explains. She first noticed he had problems when he was around 2 years old: He was slow, both developmentally and socially. The patient was diagnosed with Landau-Kleffner syndrome, a disorder in which children with previously normal language development undergo a deterioration in language skills related to seizure-like abnormalities. Hyperactivity, decreased attention, distractibility, temper tantrums, aggressiveness, and social withdrawal are also a part of this illness. The patient underwent surgery, which temporarily stopped his seizures, but they have resumed. A post-surgery video EEG (electroencephalograph) showed some abnormal activity, but the patient's MRI (magnetic resonance imaging) results were "mostly normal." These tests revealed his problems are based in the area of the brain under his left temple. His mother is hopeful PET will reveal whether more surgery will help.
Once the patient has settled, the technologists do an autotransmission scan that records the patient's position. The patient is then injected with FDG--the metabolic agent--and the staff waits for 20 minutes for it to accumulate in the brain cells. The PET scan that follows takes another 20 to 30 minutes. The images take approximately one hour to process. During any waiting time, another patient can be scanned or the technologists can make phone calls, check the appointment book, review other cases, and log information.
Unfortunately, just when it appears the scan is going smoothly, the child wakes up in the middle of the fourth frame and the technologists are forced to make an "emergency stop." The fourth frame is now useless because of too much movement. Ms. Manoj observes a few frames on the computer screen to make sure some information has been recorded; the team determines that enough information was gathered in the first three frames.
Free to go, the child is detached from the pulse oximeter, and the PET team endures a little more struggling. "This is a special day; nobody ever kicked before," jokes Leo Delacruz, supervisor of the PET suite. Still groggy from the sedative, the patient manages to say, "Juice please!" "What, do you think you gave blood?" his mother asks. The technologists laugh and clap to congratulate the patient. "All done!" they say.
"F our patients today--a new patient every two hours!" Mr. Delacruz exclaims as he prepares for a full-body scan on an elderly male with a history of colon cancer. The patient received radiation therapy after a tumor was removed, but a later chest X-ray revealed a
5 cm nodule, and another chest X-ray showed a second nodule of 2 cm. Today's time-consuming study will focus on the patient's chest, abdomen, and pelvis, scanning for possible regrowth of cancerous cells.
Dr. Angela Lignelli, the PET radiology fellow, informs the patient's daughter that she needs to insert a catheter into her father's bladder before the scan. The daughter becomes uncomfortable because her mother recently experienced serious complications caused by long-term use of a catheter. Dr. Lignelli explains that complications are normal in long-term catheter placement, but the catheter inserted into her father's bladder will be only temporary--three hours at the most. The catheter should not cause any problems. "The only possible risk," Dr. Lignelli says, "is a minor infection that could be treated with antibiotics, and I'll tell you the symptoms to look for."
The patient's daughter leaves to contact her mother for approval. Afterward, she tells Dr. Lignelli, "I discussed it with my mother, and she says, 'If it has to be...'" Pleased, Dr. Lignelli moves toward the back of the suite to insert the catheter. Later, when the daughter asks Dr. Lignelli about her father's complaints of a burning sensation, the doctor tells her some discomfort is to be expected.
The patient is run through the scanner for a transmission scan, sometimes referred to as "a poor man's CT" because the anatomical image is free of charge (included in the price for the PET scan), for 36 minutes. Instead of using the positrons from the FDG to form an image, a transmission scan uses external radioactive rods that "transmit" radioactivity though the body to form an image. The transmission scan is necessary to correct for minor movement and variations in thickness of the body and is what gives PET its high degree of accuracy. The technologists then inject the radioactive mixture and wait 50 minutes for it to be absorbed by the cells. The full body scan will take 28 minutes to complete, seven minutes per frame. Only four frames are necessary for this scan because the patient is short; a taller patient would require a longer scan.
While the patient is in the scanner, Dr. Jeff Plutchok, postdoctoral residency fellow in radiology, shows Dr. Lignelli films on the film illuminator. As they examine two sets of scans from the same patient, Dr. Plutchok refers to the first set, taken last June, as "old-fashioned PET" and compares them to a scan taken in May of 1996. "This technology has improved quickly," he says.
T he final scan of the day is a cardiac scan on a middle-aged diabetic male experiencing non-exertion chest pain. Dr. Kenneth Sampong, postdoctoral clinical fellow in medicine, and Mr. Delacruz prepare the patient's injection according to his weight; "150 pounds equals approximately 8 ccs," they agree.
The light over the pneumatic chute marked "carrier arrival" lights up when the isotope arrives. "Dose is here," Ms. Manoj announces. The time of the arrival of the injection is logged. "Computer ready?" Mr. Delacruz asks. "Computer ready," Ms. Manoj answers. "Start!" he says.
The cardiac scan patient is connected to a vice that squeezes a syringe, allowing for a timed flow of the injection for two minutes. The second injection induces stress for four minutes to test the blood vessels. Then the patient is given the radioactive ammonia injection to test the flow of blood to the heart muscle. Following the perfusion test, the patient is given FDG; after 30 minutes, another PET scan is taken to test for the amount of heart muscle still alive. The patient has EKG leads attached to his chest, essential during a stress test.
"Are you feeling a lot of stress in the room?" Dr. Plutchok jokes in the front room of the suite. "That's because we're doing a stress test! When you're feeling lively, we're probably doing the viability test!"
To that, Mr. Delacruz responds, "What do you call it when a cardiac patient reschedules?" "A change of heart!" he says, quick to deliver his punch line before the others get a chance to answer. "And what about a neuro patient?" he continues. "A change of mind!"
PET Center officials have no information on the cardiac patient who felt too uncomfortable and claustrophobic to remain still for the PET scan and opted to leave.
The brain scan of the 9-year-old boy revealed the focal area of the patient's seizures, but additional testing is needed before doctors recommend more surgery.
The full body scan in the elderly former cancer patient showed the 2 cm nodule in the patient's chest was hypermetabolic (the growth lit up in the scan), leading doctors to believe the growth is cancerous. Despite this discovery, the patient decided to postpone any action, but he will follow up later with a CT scan and, possibly, another PET scan.
The cardiac scan in the diabetic male with chest pain revealed dead heart tissue, indicating the patient would not benefit from surgery.
Decisions Made Easier
Decisions are never easy, particularly when health swings in the balance, but Dr. Ernest De Salvo, director of the Kreitchman Center, regards PET (positron emission tomography) as an excellent decision-making tool that helps clarify options for patients. PET is an accurate, non-invasive, and cost-effective diagnostic method that allows real-time imaging of physiologic and biochemical functions in virtually every organ in the body. Columbia's PET center is the only one in the New York metropolitan area that offers clinical applications for all three subspecialties of cardiology, oncology, and neurology.
In cardiology, PET is used to determine the extent of coronary artery disease and damage to muscle caused by the obstruction. It can determine whether patients will benefit from revascularization or need a transplant and if patients who have undergone revascularization but have developed recurrent chest discomfort are suffering from ischemia (low blood flow). PET is considered the gold standard in identifying viable myocardial tissue. While Thallium SPECT (single photon emission computed tomography) imaging often overestimates the frequency and severity of myocardial infarction--making living but dormant heart tissue appear dead 20 percent to 25 percent of the time--PET scans will detect living tissue in those same areas.
In neurology, PET scans are the best way to differentiate recurrent brain tumors from radiation fibrosis or necrosis. PET also offers differential diagnosis for psychiatric diseases, especially schizophrenia, depression, and substance abuse; assesses head trauma, cerebrovascular disease, and movement disorders; and provides the best way to localize an area of the brain that has been causing epileptic seizures that can't be controlled by medications.
In oncology, full-body PET scans can detect all types of cancers, actively lighting up the sites where the cancer has taken up the radioactive glucose mixture. But the greatest value of PET, Dr. De Salvo says, is in diagnosing, staging, and re-staging malignancies (particularly lung and breast cancers, recurrent colorectal cancer, and lymphomas) and in identifying post-treatment tumor recurrence.
Dr. De Salvo explains that PET approaches 100 percent sensitivity (meaning no false negatives) and 100 percent specificity (meaning no false positives) in many cancers. In comparison, CT (computerized tomography) scans can be quite sensitive but not very specific. "There is no perfect test," says Dr. De Salvo, "but PET is better than anything we currently have when used correctly and in the right disease states." And PET is at its best when used with CT, which gives accurate anatomical information.
The PET Center usually schedules anywhere from one to three clinical appointments per day, coordinating schedules with the research department, which uses approximately 60 percent of PET's time. The PET Center is now used 70 percent of the time to scan for cancer, 20 percent for brain scans, and 10 percent for cardiac scans.
Dr. De Salvo's role is to coordinate and teach the clinical uses of PET and to establish Columbia as the premier clinical PET site in the New York metro area. It seems to be working: Since he began in February 1996, the PET Center has recruited 150 to 200 patients. PET is user friendly to patients and physicians and is a cost-saving technique when used correctly. One $2,400 test can prove less expensive than multiple other non-interventional diagnostic tests.
A Tour of the Morton A. Kreitchman PET Center
Before a PET scan, patients receive an injection of a substance labeled with a positron-emitting isotope produced in the Kreitchman PET Center's cyclotron, a machine located in the basement of Milstein Hospital that manufactures radioactive carbon, oxygen, fluorine, and nitrogen. The rapid disintegration of radioactive isotopes generates photons within the body that PET detects and translates into computerized data and images. Because the isotopes decay so quickly it is necessary to deliver the injections to patients immediately before scanning, making it very important to have a cyclotron near the scanner. The Kreitchman Center has a pneumatic tube system, through which the cyclotron team delivers the injections directly from the basement to the third floor PET suite. The Kreitchman Center is one of only two facilities in New York City with both a PET scanner and a cyclotron.
The administration office, located on the second floor of Milstein Hospital, is home base for the director of the Kreitchman PET Center, the general manager, the office supervisor, and the radiology fellow. Patients stop by this office before their scans for patient registration. The office helps patients secure insurance coverage when possible.
One flight above, the PET radiology suite is divided into an observation area, the scanning room, and an examination room. The front room of the suite contains two computers, a photo printer, a film illuminator, and a chute from the pneumatic tube system. The technologists can keep an eye on the patients in the scanner through an observation window and two TV monitors; they can hear patients through a small intercom (a Sony Babycall monitor).
Beyond the observation window, in the back half of the suite, is the PET scanner and, further back, an examination room, where patients are prepped for scanning while another patient is still undergoing the procedure.
The center is named for Morton A. Kreitchman, president of Valcor Engineering, who was a patient of Dr. Paul J. Cannon, the Harold Ames Hatch Professor of Medicine. Dr. Cannon encouraged Mr.
Kreitchman's interest in medical technology, including PET. After Mr. Krietchman died in the late 1980s, his family memorialized his interest by providing a significant portion of the funds needed to create the PET Center.