BOSTON--Sedated and sand-bagged, a large gray-and-white dog named Poochie lies motionless on a gurney. His mouth is wedged open to allow the linear accelerator above his head to aim radiation directly at the malignant tumor blocking his nasal passages.

Poochie is not a prize-winning show dog or a rare purebred. A rather ordinary-looking animal whose feathery tail and long muzzle suggest a collie or shepherd heritage, he is simply a well-loved pet.

So, when he was diagnosed with malignant cancer, his Connecticut owners decided that radiation treatment at Boston's Angell Memorial Hospital--know to most as the Mayo Clinic of veterinary medicine--was worth the travel and expense.

"This is a very good, very updated center," says radiation technician Carla Peterson heaving Poochie into an unnatural-looking position on his back and balancing him with sand-bags.

Peterson should know, because she is one of several staff members who began their medical career in human--not veterinary--medicine.

"It's like treating children, almost," Peterson says. "You can't explain 'you have cancer' to a dog or a cat."

Although she admits she misses chatting with her patients, she and other hospital officials are proud that Angell compares favorably with human facilities.

"It's as good as some of the human cancer treatment centers," says Melissa Bassett, spokesperson for the hospital and for the Massachusetts Society for the Prevention of Cruelty to Animals (MSPCA), who says she frequently gets comments about her last name.

In addition to the linear accelerator that directs high doses of radiation at tumors like Poochie's, Angell boasts a state-of-the-art CT ("CAT") scanner to determine the size and shape of cancer areas and a three-dimensional treatment planning system to plan the radiation therapy.

Angell, the only veterinary radiation oncology program in New England, is one of a handful in the country. Before Angell's center became fully operational in 1997, cancer-stricken house-pets had to travel to New York for treatment.

Now Angell gives radiation therapy to as many as 12 dogs and cats dai- ure to rise. The hospital's yearly caseload hasremained at around 45,000 for several years, butlast year Angell's doctors treated anunprecedented 50,000 cases.

"Angell is becoming more and more well-known,and more and more a referral hospital," Bassettsays. For example, local veterinarians'after-hours answering machines invariably referemergency callers to Angell, she says.

And the hospital's innovation is not limited tocancer. Cats suffering from kidney disease--amajor cause of feline death--can now benefit froma recent donor program developed by Angellveterinarians and ethical advisors.

The hospital has performed only about a dozenkidney transplants, according to Bassett'sestimate.

"There might be some ethical problems," Bassettsays, "but it's worked well so far."

In addition to cancer care and kidneytransplants, Angell has over 15 areas ofspecialization, including ophthalmology, emergencycare, avian medicine and even plastic surgery.

"Almost any specialization you have in humanmedicine, we probably have here," Bassett says.

Eventually, however, the similarity betweenAngell and a human hospital begins to break down.

Across the hall from the intensive care unitand its familiar tangle of oxygen tanks andintravenous tubing is the wildlife ward, wheresick and injured wildlife is cared for until itcan be transported to the New England WildlifeCenter.

And Angell doesn't look like a human hospital.The long, drab corridors of the hospital stillresemble the seminary and Catholic boys' schoolthat occupied the building until Angell moved inin 1976.

Examining rooms are former dormitories, Bassettsays, and the shelter for homeless animals is,appropriately enough, the former chapel.

Angell, like the other six MSPCA shelters, seesfar more homeless animals than it can find homesfor.

Kathy Gorham, the shelter's animal careprovider, says she tries her best to keep theanimals happy, but they often get anxious in theshelter's close quarters.

"This is something I tell people never to do,"says Gorham, batting a kitten's paw through thebars of the cage.

"Playing finger games with a cat, you're justinviting a scratch," she says, displaying a handcross-hatched with red lines