BOSTON (AP) _ Most medical experts agree the risk of getting AIDS from a rape is small, but tell that to someone like Diana.

Diana was raped in 1988, and her assailant was arrested. Her horror was magnified when the man, an intravenous drug user, died of AIDS in prison.

''I know that there was and is a real threat to me,'' she said. ''He didn't kill me that night, but he still could murder me today even though he's dead.''

She is not alone in her fears.

''It's a double whammy,'' said Robin Einbinder, assistant director of the rape program at New York's Mount Sinai Medical Center. ''You get raped and your first reaction is, 'Oh my God, that person probably has AIDS.'''

The second reaction, in cases where a suspect is arrested, is often ''Can this man be tested for AIDS against his will?'' And the answer to that question is one that is being grappled with by state legislatures, by doctors and by rape counselors across the nation.

''A lot of women are bringing it up,'' said Sharon Vardatira, director of the Boston Area Rape Crisis Center. ''It's clearly become a really hot topic.''

Some who are opposed to this testing say the money is better spent on treatment and counseling, while others say testing is a violation of the suspect's civil liberties. But supporters say early results would ease tension and let victims decide whether to undergo AIDS treatments.

The FBI said 94,500 rapes were reported in 1989, the last year for which figures are available. No one knows how many rapes go unreported, but the Bureau of Justice Statistics estimated there were 135,000 rapes that year.

Statistics on how many people get AIDS from rape are rare, partly because it is difficult to link transmission of the virus to a single exposure.

The virus cannot be detected in a blood test until at least several months after exposure. So an AIDS test right after an assault would show the victim's HIV status before the rape, but not whether transmission occurred because of the assault.

Similarly, a positive test of a rapist does not always prove the suspect was responsible for passing on the virus.

''There is no medical justification that testing the defendant would be useful,'' said Liz Cooper, staff counsel of the AIDS Project of the American Civil Liberties Union in New York. ''Even if he tests negative, it may be that he himself is in a window period, and is infected.''

Many states have decided the victim has the right to know whether the attacker carries the virus. At least 22 states, including Florida, Illinois and California, mandate testing of convicted sex offenders.

''This is information that is valuable and useful to the victim and it's something the victims felt is very important to have,'' said Pat Gleason, Florida's assistant attorney general. ''Any medical questions that might be there, the answers are being made available.''

But the Washington Legislature is considering taking a step farther. A bill to allow testing of suspects charged with rape has passed in the Washington House and is awaiting action in the Senate.

That bill was inspired by Stephanie Allen-Kela, who was 15 years old and three months pregnant when she was raped in suburban Seattle.

She worried she might have gotten AIDS. And she worried out loud, bringing her plight into the political arena.

''If you don't think about it, it's still there, it's kind of hanging over your head like unfinished business,'' said Allen-Kela, now 17, the granddaughter of entertainer Steve Allen. ''You're angry because there's nothing you can do about it, and nobody can help you.''

Six months after giving birth, she learned her attacker did not have AIDS.

A bill pending in the Illinois Legislature would allow a rapist knowingly carrying the AIDS virus to be charged with murder if the victim dies.

''The way it's written, it's probably rather unenforceable,'' said Chet Kelly, an AIDS expert at the Illinois Department of Public Health. ''From the point of infection until death can be 10 years or more.''

Some women's advocates fear that AIDS is obscuring the tragedy of a crime they believe has been largely ignored.

''It's ironic that when people are talking about rape today, it's still secondary to the HIV infection,'' said Denise McWilliams, a gay rights activist in Boston. ''The end of the line thing that has to be looked at is the extent to which women have been subject to sexual assault.''

Ellen Kerr takes the issue a step further.

''What do you do about a situation which you have no control over at all?'' said Kerr, coordinator of Pittsburgh Action Against Rape. ''To have someone able to control you not only for the time of the assault but for years later?''

Diana, the rape victim, continues to live in fear, though her latest AIDS test was negative. She dismisses talk of the rights of rape suspects.

''What about my rights and the rights of any victim that is like me?'' she said. ''The fact is that rape doesn't kill you, but AIDS does.''